update fb-specific dependencies by running update_dependencies.sh

Update fbcode_config4.8.1.sh to use update_dependencies.sh
Summary: This patch update fbcode_config4.8.1.sh to get it's dependencies the same way we updated fbcode_config.sh in D53037 as a result zstd is upgraded to 0.4.7 instead of 0.4.5 Test Plan: make clean && ROCKSDB_FBCODE_BUILD_WITH_481=1 make check -j64 make clean && ROCKSDB_FBCODE_BUILD_WITH_481=1 USE_CLANG=1 make check -j64 Reviewers: yhchiang, andrewkr, rven, kradhakrishnan, sdong Reviewed By: sdong Subscribers: dhruba Differential Revision: https://reviews.facebook.net/D53355 (cherry picked from commit 77ef87ccb0)
2026-11-06 02:52:35 -05:00 · 2016-02-18 15:13:33 -08:00 · 2016-02-18 15:12:29 -08:00 · 2016-02-18 15:11:14 -08:00 · 2016-02-18 15:11:01 -08:00 · 2016-02-18 14:40:13 -08:00
358 changed files with 22714 additions and 6441 deletions
@@ -34,7 +34,7 @@ before_script:
 # as EnvPosixTest::AllocateTest expects within the Travis OpenVZ environment.
 script:
  - if [[ "${TRAVIS_OS_NAME}" == 'linux' ]]; then OPT=-DTRAVIS CLANG_FORMAT_DIFF=/tmp/clang-format-diff.py make format || true; fi
-  - OPT=-DTRAVIS V=1 make -j4 check && OPT=-DTRAVIS V=1 make clean jclean rocksdbjava jtest
+  - OPT=-DTRAVIS V=1 make -j4 check && OPT=-DTRAVIS V=1 make clean jclean rocksdbjava jtest && make clean && OPT="-DTRAVIS -DROCKSDB_LITE" V=1 make -j4 check

 notifications:
    email:
@@ -14,10 +14,16 @@
 # 3. Run cmake to generate project files for Windows, add more options to enable required third-party libraries.
 #    See thirdparty.inc for more information.
 #        sample command: cmake -G "Visual Studio 12 Win64" -DGFLAGS=1 -DSNAPPY=1 -DJEMALLOC=1 ..
-# 4. Then build the project in debug mode (you may want to add /m:<N> flag to run msbuild in <N> parallel threads)
-#        msbuild ALL_BUILD.vcxproj
+#        OR for VS Studio 15 cmake -G "Visual Studio 14 Win64" -DGFLAGS=1 -DSNAPPY=1 -DJEMALLOC=1 ..
+# 4. Then build the project in debug mode (you may want to add /m[:<N>] flag to run msbuild in <N> parallel threads
+#                                          or simply /m ot use all avail cores)
+#        msbuild rocksdb.sln
+#
+#        rocksdb.sln build features exclusions of test only code in Release. If you build ALL_BUILD then everything
+#        will be attempted but test only code does not build in Release mode.
+#
 # 5. And release mode (/m[:<N>] is also supported)
-#        msbuild ALL_BUILD.vcxproj /p:Configuration=Release
+#        msbuild rocksdb.sln /p:Configuration=Release
 #

 cmake_minimum_required(VERSION 2.6)
@@ -31,7 +37,14 @@ string(REGEX REPLACE "(..)/(..)/..(..).*" "\\1/\\2/\\3" DATE ${DATE})
 string(REGEX REPLACE "(..):(.....).*" " \\1:\\2" TIME ${TIME})
 string(CONCAT GIT_DATE_TIME ${DATE} ${TIME})

-execute_process(COMMAND $ENV{COMSPEC} " /C git rev-parse HEAD 2>nil" OUTPUT_VARIABLE GIT_SHA)
+find_package(Git)
+
+if (GIT_FOUND AND EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/.git")
+    execute_process(COMMAND $ENV{COMSPEC} /C ${GIT_EXECUTABLE} -C ${CMAKE_CURRENT_SOURCE_DIR} rev-parse HEAD OUTPUT_VARIABLE GIT_SHA)
+else()
+    set(GIT_SHA 0)
+endif()
+
 string(REGEX REPLACE "[^0-9a-f]+" "" GIT_SHA ${GIT_SHA})

 set(BUILD_VERSION_CC ${CMAKE_CURRENT_SOURCE_DIR}/util/build_version.cc)
@@ -46,7 +59,8 @@ add_custom_command(OUTPUT ${BUILD_VERSION_CC}
 add_custom_target(GenerateBuildVersion DEPENDS ${BUILD_VERSION_CC})

 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /Zi /nologo  /EHsc /GS /Gd /GR /GF /fp:precise /Zc:wchar_t /Zc:forScope /errorReport:queue")
-set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /FC /d2Zi+ /W3 /WX /wd4018 /wd4100 /wd4101 /wd4127 /wd4189 /wd4200 /wd4244 /wd4267 /wd4296 /wd4305 /wd4307 /wd4309 /wd4512 /wd4701 /wd4702 /wd4800 /wd4804 /wd4996")
+
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /FC /d2Zi+ /W3 /WX /wd4127 /wd4800 /wd4996 /wd4351")

 # Used to run CI build and tests so we can run faster
 set(OPTIMIZE_DEBUG_DEFAULT 0)        # Debug build is unoptimized by default use -DOPTDBG=1 to optimize
@@ -83,6 +97,7 @@ set(LIBS ${ROCKSDB_LIBS} ${THIRDPARTY_LIBS} ${SYSTEM_LIBS})

 add_subdirectory(third-party/gtest-1.7.0/fused-src/gtest)

+# Main library source code
 set(SOURCES
        db/builder.cc
        db/c.cc
@@ -130,6 +145,9 @@ set(SOURCES
        db/write_batch_base.cc
        db/write_controller.cc
        db/write_thread.cc
+        memtable/hash_cuckoo_rep.cc
+        memtable/hash_linklist_rep.cc
+        memtable/hash_skiplist_rep.cc
        port/stack_trace.cc
        port/win/env_win.cc
        port/win/port_win.cc
@@ -163,6 +181,7 @@ set(SOURCES
        table/plain_table_reader.cc
        table/table_properties.cc
        table/two_level_iterator.cc
+        tools/sst_dump_tool.cc
        tools/dump/db_dump_tool.cc
        util/arena.cc
        util/auto_roll_logger.cc
@@ -172,10 +191,10 @@ set(SOURCES
        util/coding.cc
        util/compaction_job_stats_impl.cc
        util/comparator.cc
+        util/concurrent_arena.cc
        util/crc32c.cc
        util/db_info_dumper.cc
        util/delete_scheduler_impl.cc
-        util/db_test_util.cc
        util/dynamic_bloom.cc
        util/env.cc
        util/env_hdfs.cc
@@ -184,14 +203,11 @@ set(SOURCES
        util/file_reader_writer.cc
        util/filter_policy.cc
        util/hash.cc
-        util/hash_cuckoo_rep.cc
-        util/hash_linklist_rep.cc
-        util/hash_skiplist_rep.cc
        util/histogram.cc
        util/instrumented_mutex.cc
        util/iostats_context.cc
-        util/ldb_cmd.cc
-        util/ldb_tool.cc
+        tools/ldb_cmd.cc
+        tools/ldb_tool.cc
        util/logging.cc
        util/log_buffer.cc
        util/memenv.cc
@@ -202,12 +218,13 @@ set(SOURCES
        util/options_builder.cc
        util/options_helper.cc
        util/options_parser.cc
+        util/options_sanity_check.cc
        util/perf_context.cc
        util/perf_level.cc
+        util/random.cc
        util/rate_limiter.cc
        util/skiplistrep.cc
        util/slice.cc
-        util/sst_dump_tool.cc
        util/statistics.cc
        util/status.cc
        util/status_message.cc
@@ -218,7 +235,6 @@ set(SOURCES
        util/thread_local.cc
        util/thread_status_impl.cc
        util/thread_status_updater.cc
-        util/thread_status_updater_debug.cc
        util/thread_status_util.cc
        util/thread_status_util_debug.cc
        util/vectorrep.cc
@@ -229,13 +245,16 @@ set(SOURCES
        utilities/document/document_db.cc
        utilities/document/json_document.cc
        utilities/document/json_document_builder.cc
+        utilities/env_mirror.cc
        utilities/flashcache/flashcache.cc
        utilities/geodb/geodb_impl.cc
        utilities/leveldb_options/leveldb_options.cc
+        utilities/memory/memory_util.cc
        utilities/merge_operators/string_append/stringappend.cc
        utilities/merge_operators/string_append/stringappend2.cc
        utilities/merge_operators/put.cc
        utilities/merge_operators/uint64add.cc
+        utilities/options/options_util.cc
        utilities/redis/redis_lists.cc
        utilities/spatialdb/spatial_db.cc
        utilities/table_properties_collectors/compact_on_deletion_collector.cc
@@ -252,6 +271,13 @@ set(SOURCES
        utilities/write_batch_with_index/write_batch_with_index_internal.cc
 )

+# For test util library that is build only in DEBUG mode
+# and linked to tests. Add test only code that is not #ifdefed for Release here.
+set(TESTUTIL_SOURCE
+    db/db_test_util.cc
+    util/thread_status_updater_debug.cc
+)
+
 add_library(rocksdblib${ARTIFACT_SUFFIX} ${SOURCES})
 set_target_properties(rocksdblib${ARTIFACT_SUFFIX} PROPERTIES COMPILE_FLAGS "/Fd${CMAKE_CFG_INTDIR}/rocksdblib${ARTIFACT_SUFFIX}.pdb")
 add_dependencies(rocksdblib${ARTIFACT_SUFFIX} GenerateBuildVersion)
@@ -266,6 +292,7 @@ set(APPS
        db/memtablerep_bench.cc
        table/table_reader_bench.cc
        tools/db_stress.cc
+        tools/write_stress.cc
        tools/db_repl_stress.cc
        tools/sst_dump.cc
        tools/dump/rocksdb_dump.cc
@@ -278,6 +305,7 @@ set(C_TESTS db/c_test.c)
 set(TESTS
        db/column_family_test.cc
        db/compact_files_test.cc
+        db/compaction_iterator_test.cc
        db/compaction_job_test.cc
        db/compaction_job_stats_test.cc
        db/compaction_picker_test.cc
@@ -294,17 +322,21 @@ set(TESTS
        db/db_universal_compaction_test.cc
        db/db_wal_test.cc
        db/db_tailing_iter_test.cc
+        db/db_table_properties_test.cc
        db/dbformat_test.cc
        db/deletefile_test.cc
        db/fault_injection_test.cc
        db/file_indexer_test.cc
        db/filename_test.cc
        db/flush_job_test.cc
+        db/inlineskiplist_test.cc
        db/listener_test.cc
        db/log_test.cc
+        db/manual_compaction_test.cc
        db/memtable_list_test.cc
        db/merge_test.cc
        db/merge_helper_test.cc
+        db/options_file_test.cc
        db/perf_context_test.cc
        db/plain_table_db_test.cc
        db/prefix_test.cc
@@ -326,7 +358,9 @@ set(TESTS
        table/merger_test.cc
        table/table_test.cc
        tools/db_sanity_test.cc
+        tools/ldb_cmd_test.cc
        tools/reduce_levels_test.cc
+        tools/sst_dump_test.cc
        util/arena_test.cc
        util/autovector_test.cc
        util/auto_roll_logger_test.cc
@@ -334,6 +368,7 @@ set(TESTS
        util/cache_test.cc
        util/coding_test.cc
        util/crc32c_test.cc
+        util/delete_scheduler_test.cc
        util/dynamic_bloom_test.cc
        util/env_test.cc
        util/event_logger_test.cc
@@ -341,14 +376,11 @@ set(TESTS
        util/file_reader_writer_test.cc
        util/heap_test.cc
        util/histogram_test.cc
-        util/ldb_cmd_test.cc
-        util/manual_compaction_test.cc
        util/memenv_test.cc
        util/mock_env_test.cc
        util/options_test.cc
        util/rate_limiter_test.cc
        util/slice_transform_test.cc
-        util/sst_dump_test.cc
        util/thread_list_test.cc
        util/thread_local_test.cc
        utilities/backupable/backupable_db_test.cc
@@ -356,7 +388,9 @@ set(TESTS
        utilities/document/document_db_test.cc
        utilities/document/json_document_test.cc
        utilities/geodb/geodb_test.cc
+        utilities/memory/memory_test.cc
        utilities/merge_operators/string_append/stringappend_test.cc
+        utilities/options/options_util_test.cc
        utilities/redis/redis_lists_test.cc
        utilities/spatialdb/spatial_db_test.cc
        utilities/table_properties_collectors/compact_on_deletion_collector_test.cc
@@ -366,7 +400,7 @@ set(TESTS
        utilities/write_batch_with_index/write_batch_with_index_test.cc
 )

-set(EXES ${APPS} ${TESTS})
+set(EXES ${APPS})

 foreach(sourcefile ${EXES})
    string(REPLACE ".cc" "" exename ${sourcefile})
@@ -375,12 +409,42 @@ foreach(sourcefile ${EXES})
    target_link_libraries(${exename}${ARTIFACT_SUFFIX} ${LIBS})
 endforeach(sourcefile ${EXES})

-# C executables must link to a shared object
-set(C_EXES ${C_TESTS})
+# test utilities are only build in debug
+set(TESTUTILLIB testutillib${ARTIFACT_SUFFIX})
+add_library(${TESTUTILLIB} STATIC ${TESTUTIL_SOURCE})
+set_target_properties(${TESTUTILLIB} PROPERTIES COMPILE_FLAGS "/Fd${CMAKE_CFG_INTDIR}/testutillib${ARTIFACT_SUFFIX}.pdb")
+set_target_properties(${TESTUTILLIB}
+      PROPERTIES EXCLUDE_FROM_DEFAULT_BUILD_RELEASE 1
+      EXCLUDE_FROM_DEFAULT_BUILD_MINRELEASE 1
+      EXCLUDE_FROM_DEFAULT_BUILD_RELWITHDEBINFO 1
+      )

-foreach(sourcefile ${C_EXES})
+# Tests are excluded from Release builds
+set(TEST_EXES ${TESTS})
+
+foreach(sourcefile ${TEST_EXES})
+    string(REPLACE ".cc" "" exename ${sourcefile})
+    string(REGEX REPLACE "^((.+)/)+" "" exename ${exename})
+    add_executable(${exename}${ARTIFACT_SUFFIX} ${sourcefile})
+    set_target_properties(${exename}${ARTIFACT_SUFFIX}
+      PROPERTIES EXCLUDE_FROM_DEFAULT_BUILD_RELEASE 1
+      EXCLUDE_FROM_DEFAULT_BUILD_MINRELEASE 1
+      EXCLUDE_FROM_DEFAULT_BUILD_RELWITHDEBINFO 1
+      )
+    target_link_libraries(${exename}${ARTIFACT_SUFFIX} ${LIBS} testutillib${ARTIFACT_SUFFIX})
+endforeach(sourcefile ${TEST_EXES})
+
+# C executables must link to a shared object
+set(C_TEST_EXES ${C_TESTS})
+
+foreach(sourcefile ${C_TEST_EXES})
    string(REPLACE ".c" "" exename ${sourcefile})
    string(REGEX REPLACE "^((.+)/)+" "" exename ${exename})
    add_executable(${exename}${ARTIFACT_SUFFIX} ${sourcefile})
-    target_link_libraries(${exename}${ARTIFACT_SUFFIX} rocksdb${ARTIFACT_SUFFIX})
-endforeach(sourcefile ${C_TESTS})
+    set_target_properties(${exename}${ARTIFACT_SUFFIX}
+      PROPERTIES EXCLUDE_FROM_DEFAULT_BUILD_RELEASE 1
+      EXCLUDE_FROM_DEFAULT_BUILD_MINRELEASE 1
+      EXCLUDE_FROM_DEFAULT_BUILD_RELWITHDEBINFO 1
+      )
+    target_link_libraries(${exename}${ARTIFACT_SUFFIX} rocksdb${ARTIFACT_SUFFIX} testutillib${ARTIFACT_SUFFIX})
+endforeach(sourcefile ${C_TEST_EXES})
@@ -1,5 +1,40 @@
 # Rocksdb Change Log

+## 4.4.1 (2/18/2016)
+
+## 4.4.0 (1/14/2016)
+### Public API Changes
+* Change names in CompactionPri and add a new one.
+* Deprecate options.soft_rate_limit and add options.soft_pending_compaction_bytes_limit.
+* If options.max_write_buffer_number > 3, writes will be slowed down when writing to the last write buffer to delay a full stop.
+* Introduce CompactionJobInfo::compaction_reason, this field include the reason to trigger the compaction.
+* After slow down is triggered, if estimated pending compaction bytes keep increasing, slowdown more.
+* Increase default options.delayed_write_rate to 2MB/s.
+* Added a new parameter --path to ldb tool. --path accepts the name of either MANIFEST, SST or a WAL file. Either --db or --path can be used when calling ldb.
+
+## 4.3.0 (12/8/2015)
+### New Features
+* CompactionFilter has new member function called IgnoreSnapshots which allows CompactionFilter to be called even if there are snapshots later than the key.
+* RocksDB will now persist options under the same directory as the RocksDB database on successful DB::Open, CreateColumnFamily, DropColumnFamily, and SetOptions.
+* Introduce LoadLatestOptions() in rocksdb/utilities/options_util.h.  This function can construct the latest DBOptions / ColumnFamilyOptions used by the specified RocksDB intance.
+* Introduce CheckOptionsCompatibility() in rocksdb/utilities/options_util.h.  This function checks whether the input set of options is able to open the specified DB successfully.
+
+### Public API Changes
+* When options.db_write_buffer_size triggers, only the column family with the largest column family size will be flushed, not all the column families.
+
+## 4.2.0 (11/9/2015)
+### New Features
+* Introduce CreateLoggerFromOptions(), this function create a Logger for provided DBOptions.
+* Add GetAggregatedIntProperty(), which returns the sum of the GetIntProperty of all the column families.
+* Add MemoryUtil in rocksdb/utilities/memory.h.  It currently offers a way to get the memory usage by type from a list rocksdb instances.
+
+### Public API Changes
+* CompactionFilter::Context includes information of Column Family ID
+* The need-compaction hint given by TablePropertiesCollector::NeedCompact() will be persistent and recoverable after DB recovery. This introduces a breaking format change. If you use this experimental feature, including NewCompactOnDeletionCollectorFactory() in the new version, you may not be able to directly downgrade the DB back to version 4.0 or lower.
+* TablePropertiesCollectorFactory::CreateTablePropertiesCollector() now takes an option Context, containing the information of column family ID for the file being written.
+* Remove DefaultCompactionFilterFactory.
+
+
 ## 4.1.0 (10/8/2015)
 ### New Features
 * Added single delete operation as a more efficient way to delete keys that have not been overwritten.
@@ -187,7 +222,7 @@
 * Support Multiple DB paths in universal style compactions
 * Add feature of storing plain table index and bloom filter in SST file.
 * CompactRange() will never output compacted files to level 0. This used to be the case when all the compaction input files were at level 0.
-* Added iterate_upper_bound to define the extent upto which the forward iterator will return entries. This will prevent iterating over delete markers and overwritten entries for edge cases where you want to break out the iterator anyways. This may improve perfomance in case there are a large number of delete markers or overwritten entries.
+* Added iterate_upper_bound to define the extent upto which the forward iterator will return entries. This will prevent iterating over delete markers and overwritten entries for edge cases where you want to break out the iterator anyways. This may improve performance in case there are a large number of delete markers or overwritten entries.

 ### Public API changes
 * DBOptions.db_paths now is a vector of a DBPath structure which indicates both of path and target size
@@ -1,19 +1,24 @@
 ## Compilation

+**Important**: If you plan to run RocksDB in production, don't compile using default 
+`make` or `make all`. That will compile RocksDB in debug mode, which is much slower
+than release mode.
+
 RocksDB's library should be able to compile without any dependency installed,
 although we recommend installing some compression libraries (see below).
 We do depend on newer gcc/clang with C++11 support.

 There are few options when compiling RocksDB:

-* [recommended] `make static_lib` will compile librocksdb.a, RocksDB static library.
+* [recommended] `make static_lib` will compile librocksdb.a, RocksDB static library. Compiles static library in release mode.

-* `make shared_lib` will compile librocksdb.so, RocksDB shared library.
+* `make shared_lib` will compile librocksdb.so, RocksDB shared library. Compiles shared library in release mode.

-* `make check` will compile and run all the unit tests
+* `make check` will compile and run all the unit tests. `make check` will compile RocksDB in debug mode.

 * `make all` will compile our static library, and all our tools and unit tests. Our tools
-depend on gflags. You will need to have gflags installed to run `make all`.
+depend on gflags. You will need to have gflags installed to run `make all`. This will compile RocksDB in debug mode. Don't
+use binaries compiled by `make all` in production.

 * By default the binary we produce is optimized for the platform you're compiling on
 (-march=native). If you want to build a portable binary, add 'PORTABLE=1' before
@@ -82,4 +87,5 @@ your make commands, like this: `PORTABLE=1 make static_lib`
  * Run: `TARGET_OS=IOS make static_lib`. When building the project which uses rocksdb iOS library, make sure to define two important pre-processing macros: `ROCKSDB_LITE` and `IOS_CROSS_COMPILE`.

 * **Windows**:
+  * For building with MS Visual Studio 13 you will need Update 4 installed.
  * Read and follow the instructions at CMakeLists.txt
@@ -33,12 +33,22 @@ quoted_perl_command = $(subst ','\'',$(perl_command))
 # with debug level 0. To compile with level 0, run `make shared_lib`,
 # `make install-shared`, `make static_lib`, `make install-static` or
 # `make install`
-DEBUG_LEVEL=1
+
+# Set the default DEBUG_LEVEL to 1
+DEBUG_LEVEL?=1

 ifeq ($(MAKECMDGOALS),dbg)
 	DEBUG_LEVEL=2
 endif

+ifeq ($(MAKECMDGOALS),clean)
+	DEBUG_LEVEL=0
+endif
+
+ifeq ($(MAKECMDGOALS),release)
+	DEBUG_LEVEL=0
+endif
+
 ifeq ($(MAKECMDGOALS),shared_lib)
 	DEBUG_LEVEL=0
 endif
@@ -63,6 +73,14 @@ ifeq ($(MAKECMDGOALS),rocksdbjavastatic)
 	DEBUG_LEVEL=0
 endif

+ifeq ($(MAKECMDGOALS),rocksdbjavastaticrelease)
+	DEBUG_LEVEL=0
+endif
+
+ifeq ($(MAKECMDGOALS),rocksdbjavastaticpublish)
+	DEBUG_LEVEL=0
+endif
+
 # compile with -O2 if debug level is not 2
 ifneq ($(DEBUG_LEVEL), 2)
 OPT += -O2 -fno-omit-frame-pointer
@@ -76,6 +94,8 @@ endif
 ifeq ($(DEBUG_LEVEL),0)
 OPT += -DNDEBUG
 DISABLE_WARNING_AS_ERROR=1
+else
+$(warning Warning: Compiling in debug mode. Don't use the resulting binary in production)
 endif

 #-----------------------------------------------
@@ -228,6 +248,7 @@ TESTS = \
 	db_tailing_iter_test \
 	db_universal_compaction_test \
 	db_wal_test \
+	db_table_properties_test \
 	block_hash_index_test \
 	autovector_test \
 	column_family_test \
@@ -253,14 +274,17 @@ TESTS = \
 	block_based_filter_block_test \
 	full_filter_block_test \
 	histogram_test \
+	inlineskiplist_test \
 	log_test \
 	manual_compaction_test \
 	memenv_test \
 	mock_env_test \
 	memtable_list_test \
 	merge_helper_test \
+	memory_test \
 	merge_test \
 	merger_test \
+	options_file_test \
 	redis_test \
 	reduce_levels_test \
 	plain_table_db_test \
@@ -288,6 +312,7 @@ TESTS = \
 	rate_limiter_test \
 	delete_scheduler_test \
 	options_test \
+	options_util_test \
 	event_logger_test \
 	cuckoo_table_builder_test \
 	cuckoo_table_reader_test \
@@ -315,17 +340,23 @@ TOOLS = \
 	sst_dump \
 	db_sanity_test \
 	db_stress \
+	write_stress \
 	ldb \
 	db_repl_stress \
 	rocksdb_dump \
 	rocksdb_undump

+# TODO: add back forward_iterator_bench, after making it build in all environemnts.
 BENCHMARKS = db_bench table_reader_bench cache_bench memtablerep_bench

-# The library name is configurable since we are maintaining libraries of both
-# debug/release mode.
+# if user didn't config LIBNAME, set the default
 ifeq ($(LIBNAME),)
+# we should only run rocksdb in production with DEBUG_LEVEL 0
+ifeq ($(DEBUG_LEVEL),0)
        LIBNAME=librocksdb
+else
+        LIBNAME=librocksdb_debug
+endif
 endif
 LIBRARY = ${LIBNAME}.a

@@ -371,7 +402,7 @@ $(SHARED3): $(SHARED4)
 endif

 $(SHARED4):
-	$(CXX) $(PLATFORM_SHARED_LDFLAGS)$(SHARED3) $(CXXFLAGS) $(PLATFORM_SHARED_CFLAGS) $(LIB_SOURCES) \
+	$(CXX) $(PLATFORM_SHARED_LDFLAGS)$(SHARED3) $(CXXFLAGS) $(PLATFORM_SHARED_CFLAGS) $(LIB_SOURCES) $(TOOL_SOURCES) \
 		$(LDFLAGS) -o $@

 endif  # PLATFORM_SHARED_EXT
@@ -395,7 +426,7 @@ dbg: $(LIBRARY) $(BENCHMARKS) tools $(TESTS)
 # creates static library and programs
 release:
 	$(MAKE) clean
-	OPT="-DNDEBUG -O2" $(MAKE) static_lib tools db_bench
+	DEBUG_LEVEL=0 $(MAKE) static_lib tools db_bench

 coverage:
 	$(MAKE) clean
@@ -544,8 +575,10 @@ check: all
 	      echo "===== Running $$t"; ./$$t || exit 1; done;          \
 	fi
 	rm -rf $(TMPD)
+ifeq ($(filter -DROCKSDB_LITE,$(OPT)),)
 	python tools/ldb_test.py
 	sh tools/rocksdb_dump_test.sh
+endif

 check_some: $(SUBSET) ldb_tests
 	for t in $(SUBSET); do echo "===== Running $$t"; ./$$t || exit 1; done
@@ -557,12 +590,12 @@ ldb_tests: ldb
 crash_test: whitebox_crash_test blackbox_crash_test

 blackbox_crash_test: db_stress
-	python -u tools/db_crashtest.py -s
-	python -u tools/db_crashtest.py
+	python -u tools/db_crashtest.py --simple blackbox 
+	python -u tools/db_crashtest.py blackbox

 whitebox_crash_test: db_stress
-	python -u tools/db_crashtest2.py -s
-	python -u tools/db_crashtest2.py
+	python -u tools/db_crashtest.py --simple whitebox
+	python -u tools/db_crashtest.py whitebox

 asan_check:
 	$(MAKE) clean
@@ -575,7 +608,7 @@ asan_crash_test:
 	$(MAKE) clean

 valgrind_check: $(TESTS)
-	for t in $(filter-out skiplist_test,$(TESTS)); do \
+	for t in $(filter-out %skiplist_test,$(TESTS)); do \
 		$(VALGRIND_VER) $(VALGRIND_OPTS) ./$$t; \
 		ret_code=$$?; \
 		if [ $$ret_code -ne 0 ]; then \
@@ -603,7 +636,7 @@ unity.a: unity.o
 	$(AM_V_at)$(AR) $(ARFLAGS) $@ unity.o

 # try compiling db_test with unity
-unity_test: db/db_test.o util/db_test_util.o $(TESTHARNESS) unity.a
+unity_test: db/db_test.o db/db_test_util.o $(TESTHARNESS) unity.a
 	$(AM_LINK)
 	./unity_test

@@ -649,6 +682,9 @@ block_hash_index_test: table/block_hash_index_test.o $(LIBOBJECTS) $(TESTHARNESS
 db_stress: tools/db_stress.o $(LIBOBJECTS) $(TESTUTIL)
 	$(AM_LINK)

+write_stress: tools/write_stress.o $(LIBOBJECTS) $(TESTUTIL)
+	$(AM_LINK)
+
 db_sanity_test: tools/db_sanity_test.o $(LIBOBJECTS) $(TESTUTIL)
 	$(AM_LINK)

@@ -703,34 +739,37 @@ crc32c_test: util/crc32c_test.o $(LIBOBJECTS) $(TESTHARNESS)
 slice_transform_test: util/slice_transform_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(AM_LINK)

-db_test: db/db_test.o util/db_test_util.o $(LIBOBJECTS) $(TESTHARNESS)
+db_test: db/db_test.o db/db_test_util.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(AM_LINK)

-db_log_iter_test: db/db_log_iter_test.o util/db_test_util.o $(LIBOBJECTS) $(TESTHARNESS)
+db_log_iter_test: db/db_log_iter_test.o db/db_test_util.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(AM_LINK)

-db_compaction_filter_test: db/db_compaction_filter_test.o util/db_test_util.o $(LIBOBJECTS) $(TESTHARNESS)
+db_compaction_filter_test: db/db_compaction_filter_test.o db/db_test_util.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(AM_LINK)

-db_compaction_test: db/db_compaction_test.o util/db_test_util.o $(LIBOBJECTS) $(TESTHARNESS)
+db_compaction_test: db/db_compaction_test.o db/db_test_util.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(AM_LINK)

-db_dynamic_level_test: db/db_dynamic_level_test.o util/db_test_util.o $(LIBOBJECTS) $(TESTHARNESS)
+db_dynamic_level_test: db/db_dynamic_level_test.o db/db_test_util.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(AM_LINK)

-db_inplace_update_test: db/db_inplace_update_test.o util/db_test_util.o $(LIBOBJECTS) $(TESTHARNESS)
+db_inplace_update_test: db/db_inplace_update_test.o db/db_test_util.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(AM_LINK)

-db_tailing_iter_test: db/db_tailing_iter_test.o util/db_test_util.o $(LIBOBJECTS) $(TESTHARNESS)
+db_tailing_iter_test: db/db_tailing_iter_test.o db/db_test_util.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(AM_LINK)

 db_iter_test: db/db_iter_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(AM_LINK)

-db_universal_compaction_test: db/db_universal_compaction_test.o util/db_test_util.o $(LIBOBJECTS) $(TESTHARNESS)
+db_universal_compaction_test: db/db_universal_compaction_test.o db/db_test_util.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(AM_LINK)

-db_wal_test: db/db_wal_test.o util/db_test_util.o $(LIBOBJECTS) $(TESTHARNESS)
+db_wal_test: db/db_wal_test.o db/db_test_util.o $(LIBOBJECTS) $(TESTHARNESS)
+	$(AM_LINK)
+
+db_table_properties_test: db/db_table_properties_test.o db/db_test_util.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(AM_LINK)

 log_write_bench: util/log_write_bench.o $(LIBOBJECTS) $(TESTHARNESS)
@@ -766,6 +805,9 @@ json_document_test: utilities/document/json_document_test.o $(LIBOBJECTS) $(TEST
 spatial_db_test: utilities/spatialdb/spatial_db_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(AM_LINK)

+env_mirror_test: utilities/env_mirror_test.o $(LIBOBJECTS) $(TESTHARNESS)
+	$(AM_LINK)
+
 ttl_test: utilities/ttl/ttl_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(AM_LINK)

@@ -826,6 +868,9 @@ table_test: table/table_test.o $(LIBOBJECTS) $(TESTHARNESS)
 block_test: table/block_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(AM_LINK)

+inlineskiplist_test: db/inlineskiplist_test.o $(LIBOBJECTS) $(TESTHARNESS)
+	$(AM_LINK)
+
 skiplist_test: db/skiplist_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(AM_LINK)

@@ -856,12 +901,18 @@ write_controller_test: db/write_controller_test.o $(LIBOBJECTS) $(TESTHARNESS)
 merge_helper_test: db/merge_helper_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(AM_LINK)

+memory_test: utilities/memory/memory_test.o $(LIBOBJECTS) $(TESTHARNESS)
+	$(AM_LINK)
+
 merge_test: db/merge_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(AM_LINK)

 merger_test: table/merger_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(AM_LINK)

+options_file_test: db/options_file_test.o $(LIBOBJECTS) $(TESTHARNESS)
+	$(AM_LINK)
+
 deletefile_test: db/deletefile_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(AM_LINK)

@@ -883,7 +934,7 @@ cuckoo_table_reader_test: table/cuckoo_table_reader_test.o $(LIBOBJECTS) $(TESTH
 cuckoo_table_db_test: db/cuckoo_table_db_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(AM_LINK)

-listener_test: db/listener_test.o $(LIBOBJECTS) $(TESTHARNESS)
+listener_test: db/listener_test.o db/db_test_util.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(AM_LINK)

 thread_list_test: util/thread_list_test.o $(LIBOBJECTS) $(TESTHARNESS)
@@ -895,10 +946,13 @@ compact_files_test: db/compact_files_test.o $(LIBOBJECTS) $(TESTHARNESS)
 options_test: util/options_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(AM_LINK)

+options_util_test: utilities/options/options_util_test.o $(LIBOBJECTS) $(TESTHARNESS)
+	$(AM_LINK)
+
 event_logger_test: util/event_logger_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(AM_LINK)

-sst_dump_test: util/sst_dump_test.o $(LIBOBJECTS) $(TESTHARNESS)
+sst_dump_test: tools/sst_dump_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(AM_LINK)

 memenv_test : util/memenv_test.o $(LIBOBJECTS) $(TESTHARNESS)
@@ -910,7 +964,7 @@ optimistic_transaction_test: utilities/transactions/optimistic_transaction_test.
 mock_env_test : util/mock_env_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(AM_LINK)

-manual_compaction_test: util/manual_compaction_test.o $(LIBOBJECTS) $(TESTHARNESS)
+manual_compaction_test: db/manual_compaction_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(AM_LINK)

 filelock_test: util/filelock_test.o $(LIBOBJECTS) $(TESTHARNESS)
@@ -934,7 +988,7 @@ transaction_test: utilities/transactions/transaction_test.o $(LIBOBJECTS) $(TEST
 sst_dump: tools/sst_dump.o $(LIBOBJECTS)
 	$(AM_LINK)

-ldb_cmd_test: util/ldb_cmd_test.o $(LIBOBJECTS) $(TESTHARNESS)
+ldb_cmd_test: tools/ldb_cmd_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(AM_LINK)

 ldb: tools/ldb.o $(LIBOBJECTS)
@@ -1029,20 +1083,23 @@ liblz4.a:
 	   cd lz4-r127/lib && make CFLAGS='-fPIC' all
 	   cp lz4-r127/lib/liblz4.a .

-# A version of each $(LIBOBJECTS) compiled with -fPIC
-java_libobjects = $(patsubst %,jl/%,$(LIBOBJECTS))
-CLEAN_FILES += jl
+# A version of each $(LIBOBJECTS) compiled with -fPIC and a fixed set of static compression libraries
+java_static_libobjects = $(patsubst %,jls/%,$(LIBOBJECTS))
+CLEAN_FILES += jls

-$(java_libobjects): jl/%.o: %.cc
-	$(AM_V_CC)mkdir -p $(@D) && $(CXX) $(CXXFLAGS) -fPIC -c $< -o $@ $(COVERAGEFLAGS)
+JAVA_STATIC_FLAGS = -DZLIB -DBZIP2 -DSNAPPY -DLZ4
+JAVA_STATIC_INCLUDES = -I./zlib-1.2.8 -I./bzip2-1.0.6 -I./snappy-1.1.1 -I./lz4-r127/lib

-rocksdbjavastatic: $(java_libobjects) libz.a libbz2.a libsnappy.a liblz4.a
+$(java_static_libobjects): jls/%.o: %.cc libz.a libbz2.a libsnappy.a liblz4.a
+	$(AM_V_CC)mkdir -p $(@D) && $(CXX) $(CXXFLAGS) $(JAVA_STATIC_FLAGS) $(JAVA_STATIC_INCLUDES) -fPIC -c $< -o $@ $(COVERAGEFLAGS)
+
+rocksdbjavastatic: $(java_static_libobjects)
 	cd java;$(MAKE) javalib;
 	rm -f ./java/target/$(ROCKSDBJNILIB)
 	$(CXX) $(CXXFLAGS) -I./java/. $(JAVA_INCLUDE) -shared -fPIC \
 	  -o ./java/target/$(ROCKSDBJNILIB) $(JNI_NATIVE_SOURCES) \
-	  $(java_libobjects) $(COVERAGEFLAGS) \
-	  libz.a libbz2.a libsnappy.a liblz4.a $(LDFLAGS)
+	  $(java_static_libobjects) $(COVERAGEFLAGS) \
+	  libz.a libbz2.a libsnappy.a liblz4.a $(JAVA_STATIC_LDFLAGS)
 	cd java/target;strip -S -x $(ROCKSDBJNILIB)
 	cd java;jar -cf target/$(ROCKSDB_JAR) HISTORY*.md
 	cd java/target;jar -uf $(ROCKSDB_JAR) $(ROCKSDBJNILIB)
@@ -1053,7 +1110,7 @@ rocksdbjavastatic: $(java_libobjects) libz.a libbz2.a libsnappy.a liblz4.a
 rocksdbjavastaticrelease: rocksdbjavastatic
 	cd java/crossbuild && vagrant destroy -f && vagrant up linux32 && vagrant halt linux32 && vagrant up linux64 && vagrant halt linux64
 	cd java;jar -cf target/$(ROCKSDB_JAR_ALL) HISTORY*.md
-	cd java;jar -uf target/$(ROCKSDB_JAR_ALL) librocksdbjni-*.so librocksdbjni-*.jnilib
+	cd java/target;jar -uf $(ROCKSDB_JAR_ALL) librocksdbjni-*.so librocksdbjni-*.jnilib
 	cd java/target/classes;jar -uf ../$(ROCKSDB_JAR_ALL) org/rocksdb/*.class org/rocksdb/util/*.class

 rocksdbjavastaticpublish: rocksdbjavastaticrelease
@@ -1064,6 +1121,13 @@ rocksdbjavastaticpublish: rocksdbjavastaticrelease
 	mvn gpg:sign-and-deploy-file -Durl=https://oss.sonatype.org/service/local/staging/deploy/maven2/ -DrepositoryId=sonatype-nexus-staging -DpomFile=java/rocksjni.pom -Dfile=java/target/rocksdbjni-$(ROCKSDB_MAJOR).$(ROCKSDB_MINOR).$(ROCKSDB_PATCH)-osx.jar -Dclassifier=osx
 	mvn gpg:sign-and-deploy-file -Durl=https://oss.sonatype.org/service/local/staging/deploy/maven2/ -DrepositoryId=sonatype-nexus-staging -DpomFile=java/rocksjni.pom -Dfile=java/target/rocksdbjni-$(ROCKSDB_MAJOR).$(ROCKSDB_MINOR).$(ROCKSDB_PATCH).jar

+# A version of each $(LIBOBJECTS) compiled with -fPIC
+java_libobjects = $(patsubst %,jl/%,$(LIBOBJECTS))
+CLEAN_FILES += jl
+
+$(java_libobjects): jl/%.o: %.cc
+	$(AM_V_CC)mkdir -p $(@D) && $(CXX) $(CXXFLAGS) -fPIC -c $< -o $@ $(COVERAGEFLAGS)
+
 rocksdbjava: $(java_libobjects)
 	$(AM_V_GEN)cd java;$(MAKE) javalib;
 	$(AM_V_at)rm -f ./java/target/$(ROCKSDBJNILIB)
@@ -37,3 +37,12 @@ Check out our RocksDB Protobuf merge operator at: https://github.com/vladb38/roc

 ## Santanader UK/Cloudera Profession Services
 Check out their blog post: http://blog.cloudera.com/blog/2015/08/inside-santanders-near-real-time-data-ingest-architecture/
+
+## Airbnb
+Airbnb is using RocksDB as a storage engine for their personalized search service. You can learn more about it here: https://www.youtube.com/watch?v=ASQ6XMtogMs
+
+## Pinterest
+Pinterest's Object Retrieval System uses RocksDB for storage: https://www.youtube.com/watch?v=MtFEVEs_2Vo
+
+## Smyte
+[Smyte](https://www.smyte.com/) uses RocksDB as the storage layer for their core key-value storage, high-performance counters and time-windowed HyperLogLog services.
@@ -2,10 +2,14 @@ version: 1.0.{build}
 before_build:
 - md %APPVEYOR_BUILD_FOLDER%\build
 - cd %APPVEYOR_BUILD_FOLDER%\build
- cmake -G "Visual Studio 12 Win64" ..
+- cmake -G "Visual Studio 12 Win64" -DOPTDBG=1 ..
 - cd ..
 build:
-  project: build\ALL_BUILD.vcxproj
+  project: build\rocksdb.sln
  parallel: true
  verbosity: minimal
-test: off
+test:
+test_script:
+- ps: build_tools\run_ci_db_test.ps1 -EnableRerun -Run db_test -Exclude DBTest.Randomized,DBTest.FileCreationRandomFailure -Concurrency 18
+- ps: build_tools\run_ci_db_test.ps1 -Run env_test -Concurrency 1
+
@@ -1,22 +0,0 @@
-version: 1.0.{build}
-before_build:
- md %APPVEYOR_BUILD_FOLDER%\build
- cd %APPVEYOR_BUILD_FOLDER%\build
- cmake -G "Visual Studio 12 Win64" -DOPTDBG=1 ..
- cd ..
-build:
-  project: build\ALL_BUILD.vcxproj
-  parallel: true
-  verbosity: minimal
-test:
-test_script:
- ps: build_tools\run_ci_db_test.ps1
-notifications:
-  - provider: Email
-    to:
-      - svmtrocksdb@microsoft.com
-    subject: "Build {{status}}"
-    message: "{{message}}, {{commitId}}, ..."
-    on_build_success: false
-    on_build_failure: true
-    on_build_status_changed: true
@@ -88,6 +88,9 @@ class FbcodeCppLinter extends ArcanistLinter {
  }

  private function getCppLintOutput($path) {
+     if (!array_key_exists($path, $this->rawLintOutput)) {
+       return array();
+     }
    list($output) = $this->rawLintOutput[$path];

    $msgs = array();
@@ -8,6 +8,7 @@
 #   CXX                         C++ Compiler path
 #   PLATFORM_LDFLAGS            Linker flags
 #   JAVA_LDFLAGS                Linker flags for RocksDBJava
+#   JAVA_STATIC_LDFLAGS         Linker flags for RocksDBJava static build
 #   PLATFORM_SHARED_EXT         Extension for shared libraries
 #   PLATFORM_SHARED_LDFLAGS     Flags for building shared library
 #   PLATFORM_SHARED_CFLAGS      Flags for compiling objects for shared library
@@ -44,7 +45,7 @@ fi
 # we depend on C++11
 PLATFORM_CXXFLAGS="-std=c++11"
 # we currently depend on POSIX platform
-COMMON_FLAGS="-DROCKSDB_PLATFORM_POSIX"
+COMMON_FLAGS="-DROCKSDB_PLATFORM_POSIX -DROCKSDB_LIB_IO_POSIX"

 # Default to fbcode gcc on internal fb machines
 if [ -z "$ROCKSDB_NO_FBCODE" -a -d /mnt/gvfs/third-party ]; then
@@ -181,6 +182,7 @@ esac

 PLATFORM_CXXFLAGS="$PLATFORM_CXXFLAGS ${CXXFLAGS}"
 JAVA_LDFLAGS="$PLATFORM_LDFLAGS"
+JAVA_STATIC_LDFLAGS="$PLATFORM_LDFLAGS"

 if [ "$CROSS_COMPILE" = "true" -o "$FBCODE_BUILD" = "true" ]; then
    # Cross-compiling; do not try any compilation tests.
@@ -374,6 +376,7 @@ echo "CXX=$CXX" >> "$OUTPUT"
 echo "PLATFORM=$PLATFORM" >> "$OUTPUT"
 echo "PLATFORM_LDFLAGS=$PLATFORM_LDFLAGS" >> "$OUTPUT"
 echo "JAVA_LDFLAGS=$JAVA_LDFLAGS" >> "$OUTPUT"
+echo "JAVA_STATIC_LDFLAGS=$JAVA_STATIC_LDFLAGS" >> "$OUTPUT"
 echo "VALGRIND_VER=$VALGRIND_VER" >> "$OUTPUT"
 echo "PLATFORM_CCFLAGS=$PLATFORM_CCFLAGS" >> "$OUTPUT"
 echo "PLATFORM_CXXFLAGS=$PLATFORM_CXXFLAGS" >> "$OUTPUT"
@@ -0,0 +1,16 @@
+GCC_BASE=/mnt/vol/engshare/fbcode/third-party2/gcc/4.9.x/centos6-native/1317bc4/
+CLANG_BASE=/mnt/vol/engshare/fbcode/third-party2/clang/3.7.1/centos6-native/9d9ecb9/
+LIBGCC_BASE=/mnt/gvfs/third-party2/libgcc/ea2fd1278810d3af2ea52218d2767e09d786dbd0/4.9.x/gcc-4.9-glibc-2.20/024dbc3
+GLIBC_BASE=/mnt/gvfs/third-party2/glibc/f5484f168c0e4d19823d41df052c5870c6e575a4/2.20/gcc-4.9-glibc-2.20/500e281
+SNAPPY_BASE=/mnt/gvfs/third-party2/snappy/cbf6f1f209e5bd160bdc5d971744e039f36b1566/1.1.3/gcc-4.9-glibc-2.20/e9936bf
+ZLIB_BASE=/mnt/gvfs/third-party2/zlib/6d39cb54708049f527e713ad19f2aadb9d3667e8/1.2.8/gcc-4.9-glibc-2.20/e9936bf
+BZIP2_BASE=/mnt/gvfs/third-party2/bzip2/2ddd45f0853bfc8bb1c27f0f447236a1a26c338a/1.0.6/gcc-4.9-glibc-2.20/e9936bf
+LZ4_BASE=/mnt/gvfs/third-party2/lz4/6858fac689e0f92e584224d91bdb0e39f6c8320d/r131/gcc-4.9-glibc-2.20/e9936bf
+ZSTD_BASE=/mnt/gvfs/third-party2/zstd/9c833012dea9ae6de1df2cbdcb7aebc57ba2cb39/0.5.0/gcc-4.9-glibc-2.20/e9936bf
+GFLAGS_BASE=/mnt/gvfs/third-party2/gflags/c7275a4ceae0aca0929e56964a31dafc53c1ee96/2.1.1/gcc-4.8.1-glibc-2.17/c3f970a
+JEMALLOC_BASE=/mnt/gvfs/third-party2/jemalloc/378c8f95cf28c833e121ca73432101e451c3e62a/4.0.3/gcc-4.9-glibc-2.20/a6c5e1e
+NUMA_BASE=/mnt/gvfs/third-party2/numa/ae54a5ed22cdabb1c6446dce4e8ffae5b4446d73/2.0.8/gcc-4.9-glibc-2.20/e9936bf
+LIBUNWIND_BASE=/mnt/gvfs/third-party2/libunwind/303048f72efc92ae079e62dfc84823401aecfd94/trunk/gcc-4.9-glibc-2.20/12266b1
+KERNEL_HEADERS_BASE=/mnt/gvfs/third-party2/kernel-headers/1a48835975c66d30e47770ec419758ed3b9ba010/3.10.62-62_fbk17_03959_ge29cc63/gcc-4.9-glibc-2.20/da39a3e
+BINUTILS_BASE=/mnt/gvfs/third-party2/binutils/a5b8152b2a15ce8a98808cf954fbccec825a97bc/2.25/centos6-native/da39a3e
+VALGRIND_BASE=/mnt/gvfs/third-party2/valgrind/af85c56f424cd5edfc2c97588299b44ecdec96bb/3.10.0/gcc-4.9-glibc-2.20/e9936bf
@@ -0,0 +1,16 @@
+GCC_BASE=/mnt/vol/engshare/fbcode/third-party2/gcc/4.8.1/centos6-native/cc6c9dc/
+CLANG_BASE=/mnt/vol/engshare/fbcode/third-party2/clang/3.7.1/centos6-native/9d9ecb9/
+LIBGCC_BASE=/mnt/gvfs/third-party2/libgcc/ea2fd1278810d3af2ea52218d2767e09d786dbd0/4.8.1/gcc-4.8.1-glibc-2.17/8aac7fc
+GLIBC_BASE=/mnt/gvfs/third-party2/glibc/f5484f168c0e4d19823d41df052c5870c6e575a4/2.17/gcc-4.8.1-glibc-2.17/99df8fc
+SNAPPY_BASE=/mnt/gvfs/third-party2/snappy/cbf6f1f209e5bd160bdc5d971744e039f36b1566/1.1.3/gcc-4.8.1-glibc-2.17/c3f970a
+ZLIB_BASE=/mnt/gvfs/third-party2/zlib/6d39cb54708049f527e713ad19f2aadb9d3667e8/1.2.8/gcc-4.8.1-glibc-2.17/c3f970a
+BZIP2_BASE=/mnt/gvfs/third-party2/bzip2/2ddd45f0853bfc8bb1c27f0f447236a1a26c338a/1.0.6/gcc-4.8.1-glibc-2.17/c3f970a
+LZ4_BASE=/mnt/gvfs/third-party2/lz4/6858fac689e0f92e584224d91bdb0e39f6c8320d/r131/gcc-4.8.1-glibc-2.17/c3f970a
+ZSTD_BASE=/mnt/gvfs/third-party2/zstd/9c833012dea9ae6de1df2cbdcb7aebc57ba2cb39/0.5.0/gcc-4.8.1-glibc-2.17/c3f970a
+GFLAGS_BASE=/mnt/gvfs/third-party2/gflags/c7275a4ceae0aca0929e56964a31dafc53c1ee96/2.1.1/gcc-4.8.1-glibc-2.17/c3f970a
+JEMALLOC_BASE=/mnt/gvfs/third-party2/jemalloc/378c8f95cf28c833e121ca73432101e451c3e62a/4.0.3/gcc-4.8.1-glibc-2.17/8d31e51
+NUMA_BASE=/mnt/gvfs/third-party2/numa/ae54a5ed22cdabb1c6446dce4e8ffae5b4446d73/2.0.8/gcc-4.8.1-glibc-2.17/c3f970a
+LIBUNWIND_BASE=/mnt/gvfs/third-party2/libunwind/303048f72efc92ae079e62dfc84823401aecfd94/trunk/gcc-4.8.1-glibc-2.17/675d945
+KERNEL_HEADERS_BASE=/mnt/gvfs/third-party2/kernel-headers/1a48835975c66d30e47770ec419758ed3b9ba010/3.10.62-62_fbk17_03959_ge29cc63/gcc-4.8.1-glibc-2.17/da39a3e
+BINUTILS_BASE=/mnt/gvfs/third-party2/binutils/a5b8152b2a15ce8a98808cf954fbccec825a97bc/2.25/centos6-native/da39a3e
+VALGRIND_BASE=/mnt/gvfs/third-party2/valgrind/af85c56f424cd5edfc2c97588299b44ecdec96bb/3.8.1/gcc-4.8.1-glibc-2.17/c3f970a
@@ -6,103 +6,104 @@
 # Environment variables that change the behavior of this script:
 # PIC_BUILD -- if true, it will only take pic versions of libraries from fbcode. libraries that don't have pic variant will not be included

+
+BASEDIR=`dirname $BASH_SOURCE`
+source "$BASEDIR/dependencies.sh"
+
 CFLAGS=""

-# location of libgcc
-LIBGCC_BASE="/mnt/gvfs/third-party2/libgcc/0473c80518a10d6efcbe24c5eeca3fb4ec9b519c/4.9.x/gcc-4.9-glibc-2.20/e1a7e4e"
+# libgcc
 LIBGCC_INCLUDE="$LIBGCC_BASE/include"
 LIBGCC_LIBS=" -L $LIBGCC_BASE/libs"

-# location of glibc
-GLIBC_REV=7397bed99280af5d9543439cdb7d018af7542720
-GLIBC_INCLUDE="/mnt/gvfs/third-party2/glibc/$GLIBC_REV/2.20/gcc-4.9-glibc-2.20/99df8fc/include"
-GLIBC_LIBS=" -L /mnt/gvfs/third-party2/glibc/$GLIBC_REV/2.20/gcc-4.9-glibc-2.20/99df8fc/lib"
-
-SNAPPY_INCLUDE=" -I /mnt/gvfs/third-party2/snappy/b0f269b3ca47770121aa159b99e1d8d2ab260e1f/1.0.3/gcc-4.9-glibc-2.20/c32916f/include/"
+# glibc
+GLIBC_INCLUDE="$GLIBC_BASE/include"
+GLIBC_LIBS=" -L $GLIB_BASE/lib"

+# snappy
+SNAPPY_INCLUDE=" -I $SNAPPY_BASE/include/"
 if test -z $PIC_BUILD; then
-  SNAPPY_LIBS=" /mnt/gvfs/third-party2/snappy/b0f269b3ca47770121aa159b99e1d8d2ab260e1f/1.0.3/gcc-4.9-glibc-2.20/c32916f/lib/libsnappy.a"
+  SNAPPY_LIBS=" $SNAPPY_BASE/lib/libsnappy.a"
 else
-  SNAPPY_LIBS=" /mnt/gvfs/third-party2/snappy/b0f269b3ca47770121aa159b99e1d8d2ab260e1f/1.0.3/gcc-4.9-glibc-2.20/c32916f/lib/libsnappy_pic.a"
+  SNAPPY_LIBS=" $SNAPPY_BASE/lib/libsnappy_pic.a"
 fi
-
 CFLAGS+=" -DSNAPPY"

 if test -z $PIC_BUILD; then
  # location of zlib headers and libraries
-  ZLIB_INCLUDE=" -I /mnt/gvfs/third-party2/zlib/feb983d9667f4cf5e9da07ce75abc824764b67a1/1.2.8/gcc-4.9-glibc-2.20/4230243/include/"
-  ZLIB_LIBS=" /mnt/gvfs/third-party2/zlib/feb983d9667f4cf5e9da07ce75abc824764b67a1/1.2.8/gcc-4.9-glibc-2.20/4230243/lib/libz.a"
+  ZLIB_INCLUDE=" -I $ZLIB_BASE/include/"
+  ZLIB_LIBS=" $ZLIB_BASE/lib/libz.a"
  CFLAGS+=" -DZLIB"

  # location of bzip headers and libraries
-  BZIP_INCLUDE=" -I /mnt/gvfs/third-party2/bzip2/af004cceebb2dfd173ca29933ea5915e727aad2f/1.0.6/gcc-4.9-glibc-2.20/4230243/include/"
-  BZIP_LIBS=" /mnt/gvfs/third-party2/bzip2/af004cceebb2dfd173ca29933ea5915e727aad2f/1.0.6/gcc-4.9-glibc-2.20/4230243/lib/libbz2.a"
+  BZIP_INCLUDE=" -I $BZIP2_BASE/include/"
+  BZIP_LIBS=" $BZIP2_BASE/lib/libbz2.a"
  CFLAGS+=" -DBZIP2"

-  LZ4_INCLUDE=" -I /mnt/gvfs/third-party2/lz4/79d2943e2dd7208a3e0b06cf95e9f85f05fe9e1b/r124/gcc-4.9-glibc-2.20/4230243/include/"
-  LZ4_LIBS=" /mnt/gvfs/third-party2/lz4/79d2943e2dd7208a3e0b06cf95e9f85f05fe9e1b/r124/gcc-4.9-glibc-2.20/4230243/lib/liblz4.a"
+  LZ4_INCLUDE=" -I $LZ4_BASE/include/"
+  LZ4_LIBS=" $LZ4_BASE/lib/liblz4.a"
  CFLAGS+=" -DLZ4"

-  ZSTD_REV=8df2d01673ae6afcc8c8d16fec862b2d67ecc1e9
-  ZSTD_INCLUDE=" -I /mnt/gvfs/third-party2/zstd/$ZSTD_REV/0.1.1/gcc-4.8.1-glibc-2.17/c3f970a/include"
-  ZSTD_LIBS=" /mnt/gvfs/third-party2/zstd/$ZSTD_REV/0.1.1/gcc-4.8.1-glibc-2.17/c3f970a/lib/libzstd.a"
+  ZSTD_INCLUDE=" -I $ZSTD_BASE/include/"
+  ZSTD_LIBS=" $ZSTD_BASE/lib/libzstd.a"
  CFLAGS+=" -DZSTD"
 fi

 # location of gflags headers and libraries
-GFLAGS_INCLUDE=" -I /mnt/gvfs/third-party2/gflags/0fa60e2b88de3e469db6c482d6e6dac72f5d65f9/1.6/gcc-4.9-glibc-2.20/4230243/include/"
+GFLAGS_INCLUDE=" -I $GFLAGS_BASE/include/"
 if test -z $PIC_BUILD; then
-  GFLAGS_LIBS=" /mnt/gvfs/third-party2/gflags/0fa60e2b88de3e469db6c482d6e6dac72f5d65f9/1.6/gcc-4.9-glibc-2.20/4230243/lib/libgflags.a"
+  GFLAGS_LIBS=" $GFLAGS_BASE/lib/libgflags.a"
 else
-  GFLAGS_LIBS=" /mnt/gvfs/third-party2/gflags/0fa60e2b88de3e469db6c482d6e6dac72f5d65f9/1.6/gcc-4.9-glibc-2.20/4230243/lib/libgflags_pic.a"
+  GFLAGS_LIBS=" $GFLAGS_BASE/lib/libgflags_pic.a"
 fi
 CFLAGS+=" -DGFLAGS=google"

 # location of jemalloc
-JEMALLOC_INCLUDE=" -I /mnt/gvfs/third-party2/jemalloc/bcd68e5e419efa4e61b9486d6854564d6d75a0b5/3.6.0/gcc-4.9-glibc-2.20/2aafc78/include/"
-JEMALLOC_LIB=" /mnt/gvfs/third-party2/jemalloc/bcd68e5e419efa4e61b9486d6854564d6d75a0b5/3.6.0/gcc-4.9-glibc-2.20/2aafc78/lib/libjemalloc.a"
+JEMALLOC_INCLUDE=" -I $JEMALLOC_BASE/include/"
+JEMALLOC_LIB=" $JEMALLOC_BASE/lib/libjemalloc.a"

 if test -z $PIC_BUILD; then
  # location of numa
-  NUMA_INCLUDE=" -I /mnt/gvfs/third-party2/numa/bbefc39ecbf31d0ca184168eb613ef8d397790ee/2.0.8/gcc-4.9-glibc-2.20/4230243/include/"
-  NUMA_LIB=" /mnt/gvfs/third-party2/numa/bbefc39ecbf31d0ca184168eb613ef8d397790ee/2.0.8/gcc-4.9-glibc-2.20/4230243/lib/libnuma.a"
+  NUMA_INCLUDE=" -I $NUMA_BASE/include/"
+  NUMA_LIB=" $NUMA_BASE/lib/libnuma.a"
  CFLAGS+=" -DNUMA"

  # location of libunwind
-  LIBUNWIND="/mnt/gvfs/third-party2/libunwind/1de3b75e0afedfe5585b231bbb340ec7a1542335/1.1/gcc-4.9-glibc-2.20/34235e8/lib/libunwind.a"
+  LIBUNWIND="$LIBUNWIND_BASE/lib/libunwind.a"
 fi

 # use Intel SSE support for checksum calculations
 export USE_SSE=1

-BINUTILS="/mnt/gvfs/third-party2/binutils/0b6ad0c88ddd903333a48ae8bff134efac468e4a/2.25/centos6-native/da39a3e/bin"
+BINUTILS="$BINUTILS_BASE/bin"
 AR="$BINUTILS/ar"

 DEPS_INCLUDE="$SNAPPY_INCLUDE $ZLIB_INCLUDE $BZIP_INCLUDE $LZ4_INCLUDE $ZSTD_INCLUDE $GFLAGS_INCLUDE $NUMA_INCLUDE"

-GCC_BASE="/mnt/gvfs/third-party2/gcc/1c67a0b88f64d4d9ced0382d141c76aaa7d62fba/4.9.x/centos6-native/1317bc4"
 STDLIBS="-L $GCC_BASE/lib64"

-CLANG_BASE="/mnt/gvfs/third-party2/clang/d81444dd214df3d2466734de45bb264a0486acc3/dev"
-CLANG_BIN="$CLANG_BASE/centos6-native/af4b1a0/bin"
+CLANG_BIN="$CLANG_BASE/bin"
+CLANG_LIB="$CLANG_BASE/lib"
+CLANG_SRC="$CLANG_BASE/../../src"
+
 CLANG_ANALYZER="$CLANG_BIN/clang++"
-CLANG_SCAN_BUILD="$CLANG_BASE/src/clang/tools/scan-build/scan-build"
+CLANG_SCAN_BUILD="$CLANG_SRC/clang/tools/scan-build/scan-build"

 if [ -z "$USE_CLANG" ]; then
  # gcc
  CC="$GCC_BASE/bin/gcc"
  CXX="$GCC_BASE/bin/g++"
-  
+
  CFLAGS+=" -B$BINUTILS/gold"
  CFLAGS+=" -isystem $GLIBC_INCLUDE"
  CFLAGS+=" -isystem $LIBGCC_INCLUDE"
 else
-  # clang 
-  CLANG_INCLUDE="$CLANG_BASE/gcc-4.9-glibc-2.20/74c386f/lib/clang/dev/include/"
+  # clang
+  CLANG_INCLUDE="$CLANG_LIB/clang/*/include"
  CC="$CLANG_BIN/clang"
  CXX="$CLANG_BIN/clang++"

-  KERNEL_HEADERS_INCLUDE="/mnt/gvfs/third-party2/kernel-headers/ffd14f660a43c4b92717986b1bba66722ef089d0/3.2.18_70_fbk11_00129_gc8882d0/gcc-4.9-glibc-2.20/da39a3e/include"
+  KERNEL_HEADERS_INCLUDE="$KERNEL_HEADERS_BASE/include"

  CFLAGS+=" -B$BINUTILS/gold -nostdinc -nostdlib"
  CFLAGS+=" -isystem $LIBGCC_BASE/include/c++/4.9.x "
@@ -116,7 +117,7 @@ else
 fi

 CFLAGS+=" $DEPS_INCLUDE"
-CFLAGS+=" -DROCKSDB_PLATFORM_POSIX -DROCKSDB_FALLOCATE_PRESENT -DROCKSDB_MALLOC_USABLE_SIZE"
+CFLAGS+=" -DROCKSDB_PLATFORM_POSIX -DROCKSDB_LIB_IO_POSIX -DROCKSDB_FALLOCATE_PRESENT -DROCKSDB_MALLOC_USABLE_SIZE"
 CXXFLAGS+=" $CFLAGS"

 EXEC_LDFLAGS=" $SNAPPY_LIBS $ZLIB_LIBS $BZIP_LIBS $LZ4_LIBS $ZSTD_LIBS $GFLAGS_LIBS $NUMA_LIB"
@@ -128,6 +129,6 @@ PLATFORM_LDFLAGS="$LIBGCC_LIBS $GLIBC_LIBS $STDLIBS -lgcc -lstdc++"

 EXEC_LDFLAGS_SHARED="$SNAPPY_LIBS $ZLIB_LIBS $BZIP_LIBS $LZ4_LIBS $ZSTD_LIBS $GFLAGS_LIBS"

-VALGRIND_VER="/mnt/gvfs/third-party2/valgrind/6c45ef049cbf11c2df593addb712cd891049e737/3.10.0/gcc-4.9-glibc-2.20/4230243/bin/"
+VALGRIND_VER="$VALGRIND_BASE/bin/"

 export CC CXX AR CFLAGS CXXFLAGS EXEC_LDFLAGS EXEC_LDFLAGS_SHARED VALGRIND_VER JEMALLOC_LIB JEMALLOC_INCLUDE CLANG_ANALYZER CLANG_SCAN_BUILD
@@ -4,80 +4,77 @@
 # fbcode settings.  It uses the latest g++ compiler and also
 # uses jemalloc

+BASEDIR=`dirname $BASH_SOURCE`
+source "$BASEDIR/dependencies_4.8.1.sh"
+
 # location of libgcc
-LIBGCC_BASE="/mnt/gvfs/third-party2/libgcc/7712e757d7355cb51292454ee0b7b46a467fdfed/4.8.1/gcc-4.8.1-glibc-2.17/8aac7fc"
 LIBGCC_INCLUDE="$LIBGCC_BASE/include"
 LIBGCC_LIBS=" -L $LIBGCC_BASE/libs"

 # location of glibc
-GLIBC_REV=6e40560b4e0b6d690fd1cf8c7a43ad7452b04cfa
-GLIBC_INCLUDE="/mnt/gvfs/third-party2/glibc/$GLIBC_REV/2.17/gcc-4.8.1-glibc-2.17/99df8fc/include"
-GLIBC_LIBS=" -L /mnt/gvfs/third-party2/glibc/$GLIBC_REV/2.17/gcc-4.8.1-glibc-2.17/99df8fc/lib"
+GLIBC_INCLUDE="$GLIBC_BASE/include"
+GLIBC_LIBS=" -L $GLIBC_BASE/lib"

 # location of snappy headers and libraries
-SNAPPY_INCLUDE=" -I /mnt/gvfs/third-party2/snappy/aef17f6c0b44b4fe408bd06f67c93701ab0a6ceb/1.0.3/gcc-4.8.1-glibc-2.17/43d84e2/include"
-SNAPPY_LIBS=" /mnt/gvfs/third-party2/snappy/aef17f6c0b44b4fe408bd06f67c93701ab0a6ceb/1.0.3/gcc-4.8.1-glibc-2.17/43d84e2/lib/libsnappy.a"
+SNAPPY_INCLUDE=" -I $SNAPPY_BASE/include"
+SNAPPY_LIBS=" $SNAPPY_BASE/lib/libsnappy.a"

 # location of zlib headers and libraries
-ZLIB_INCLUDE=" -I /mnt/gvfs/third-party2/zlib/25c6216928b4d77b59ddeca0990ff6fe9ac16b81/1.2.5/gcc-4.8.1-glibc-2.17/c3f970a/include"
-ZLIB_LIBS=" /mnt/gvfs/third-party2/zlib/25c6216928b4d77b59ddeca0990ff6fe9ac16b81/1.2.5/gcc-4.8.1-glibc-2.17/c3f970a/lib/libz.a"
+ZLIB_INCLUDE=" -I $ZLIB_BASE/include"
+ZLIB_LIBS=" $ZLIB_BASE/lib/libz.a"

 # location of bzip headers and libraries
-BZIP_INCLUDE=" -I /mnt/gvfs/third-party2/bzip2/c9ef7629c2aa0024f7a416e87602f06eb88f5eac/1.0.6/gcc-4.8.1-glibc-2.17/c3f970a/include/"
-BZIP_LIBS=" /mnt/gvfs/third-party2/bzip2/c9ef7629c2aa0024f7a416e87602f06eb88f5eac/1.0.6/gcc-4.8.1-glibc-2.17/c3f970a/lib/libbz2.a"
+BZIP2_INCLUDE=" -I $BZIP2_BASE/include/"
+BZIP2_LIBS=" $BZIP2_BASE/lib/libbz2.a"

-LZ4_REV=065ec7e38fe83329031f6668c43bef83eff5808b
-LZ4_INCLUDE=" -I /mnt/gvfs/third-party2/lz4/$LZ4_REV/r108/gcc-4.8.1-glibc-2.17/c3f970a/include"
-LZ4_LIBS=" /mnt/gvfs/third-party2/lz4/$LZ4_REV/r108/gcc-4.8.1-glibc-2.17/c3f970a/lib/liblz4.a"
+LZ4_INCLUDE=" -I $LZ4_BASE/include"
+LZ4_LIBS=" $LZ4_BASE/lib/liblz4.a"

-ZSTD_REV=8df2d01673ae6afcc8c8d16fec862b2d67ecc1e9
-ZSTD_INCLUDE=" -I /mnt/gvfs/third-party2/zstd/$ZSTD_REV/0.1.1/gcc-4.8.1-glibc-2.17/c3f970a/include"
-ZSTD_LIBS=" /mnt/gvfs/third-party2/zstd/$ZSTD_REV/0.1.1/gcc-4.8.1-glibc-2.17/c3f970a/lib/libzstd.a"
+ZSTD_INCLUDE=" -I $ZSTD_BASE/include"
+ZSTD_LIBS=" $ZSTD_BASE/lib/libzstd.a"

 # location of gflags headers and libraries
-GFLAGS_INCLUDE=" -I /mnt/gvfs/third-party2/gflags/1ad047a6e6f6673991918ecadc670868205a243a/1.6/gcc-4.8.1-glibc-2.17/c3f970a/include/"
-GFLAGS_LIBS=" /mnt/gvfs/third-party2/gflags/1ad047a6e6f6673991918ecadc670868205a243a/1.6/gcc-4.8.1-glibc-2.17/c3f970a/lib/libgflags.a"
+GFLAGS_INCLUDE=" -I $GFLAGS_BASE/include/"
+GFLAGS_LIBS=" $GFLAGS_BASE/lib/libgflags.a"

 # location of jemalloc
-JEMALLOC_INCLUDE=" -I /mnt/gvfs/third-party2/jemalloc/3691c776ac26dd8781e84f8888b6a0fbdbc0a9ed/dev/gcc-4.8.1-glibc-2.17/4d53c6f/include"
-JEMALLOC_LIB="/mnt/gvfs/third-party2/jemalloc/3691c776ac26dd8781e84f8888b6a0fbdbc0a9ed/dev/gcc-4.8.1-glibc-2.17/4d53c6f/lib/libjemalloc.a"
+JEMALLOC_INCLUDE=" -I $JEMALLOC_BASE/include"
+JEMALLOC_LIB="$JEMALLOC_BASE/lib/libjemalloc.a"

 # location of numa
-NUMA_REV=829d10dac0230f99cd7e1778869d2adf3da24b65
-NUMA_INCLUDE=" -I /mnt/gvfs/third-party2/numa/$NUMA_REV/2.0.8/gcc-4.8.1-glibc-2.17/c3f970a/include/"
-NUMA_LIB=" /mnt/gvfs/third-party2/numa/$NUMA_REV/2.0.8/gcc-4.8.1-glibc-2.17/c3f970a/lib/libnuma.a"
+NUMA_INCLUDE=" -I $NUMA_BASE/include/"
+NUMA_LIB=" $NUMA_BASE/lib/libnuma.a"

 # location of libunwind
-LIBUNWIND_REV=2c060e64064559905d46fd194000d61592087bdc
-LIBUNWIND="/mnt/gvfs/third-party2/libunwind/$LIBUNWIND_REV/1.1/gcc-4.8.1-glibc-2.17/675d945/lib/libunwind.a"
+LIBUNWIND="$LIBUNWIND_BASE/lib/libunwind.a"

 # use Intel SSE support for checksum calculations
 export USE_SSE=1

-BINUTILS="/mnt/gvfs/third-party2/binutils/2aff2e7b474cd3e6ab23495ad1224b7d214b9f8e/2.21.1/centos6-native/da39a3e/bin"
+BINUTILS="$BINUTILS_BASE/bin"
 AR="$BINUTILS/ar"

-DEPS_INCLUDE="$SNAPPY_INCLUDE $ZLIB_INCLUDE $BZIP_INCLUDE $LZ4_INCLUDE $ZSTD_INCLUDE $GFLAGS_INCLUDE $NUMA_INCLUDE"
+DEPS_INCLUDE="$SNAPPY_INCLUDE $ZLIB_INCLUDE $BZIP2_INCLUDE $LZ4_INCLUDE $ZSTD_INCLUDE $GFLAGS_INCLUDE $NUMA_INCLUDE"

-GCC_BASE="/mnt/gvfs/third-party2/gcc/1ec615e23800f0815d474478ba476a0adc3fe788/4.8.1/centos6-native/cc6c9dc"
 STDLIBS="-L $GCC_BASE/lib64"

 if [ -z "$USE_CLANG" ]; then
  # gcc
  CC="$GCC_BASE/bin/gcc"
  CXX="$GCC_BASE/bin/g++"
-  
+
  CFLAGS="-B$BINUTILS/gold -m64 -mtune=generic"
  CFLAGS+=" -isystem $GLIBC_INCLUDE"
  CFLAGS+=" -isystem $LIBGCC_INCLUDE"
 else
-  # clang 
-  CLANG_BASE="/mnt/gvfs/third-party2/clang/9ab68376f938992c4eb5946ca68f90c3185cffc8/3.4"
-  CLANG_INCLUDE="$CLANG_BASE/gcc-4.8.1-glibc-2.17/fb0f730/lib/clang/3.4/include"
-  CC="$CLANG_BASE/centos6-native/9cefd8a/bin/clang"
-  CXX="$CLANG_BASE/centos6-native/9cefd8a/bin/clang++"
+  # clang
+  CLANG_BIN="$CLANG_BASE/bin"
+  CLANG_LIB="$CLANG_BASE/lib"
+  CLANG_INCLUDE="$CLANG_LIB/clang/*/include"
+  CC="$CLANG_BIN/clang"
+  CXX="$CLANG_BIN/clang++"

-  KERNEL_HEADERS_INCLUDE="/mnt/gvfs/third-party2/kernel-headers/a683ed7135276731065a9d76d3016c9731f4e2f9/3.2.18_70_fbk11_00129_gc8882d0/gcc-4.8.1-glibc-2.17/da39a3e/include/"
+  KERNEL_HEADERS_INCLUDE="$KERNEL_HEADERS_BASE/include/"

  CFLAGS="-B$BINUTILS/gold -nostdinc -nostdlib"
  CFLAGS+=" -isystem $LIBGCC_BASE/include/c++/4.8.1 "
@@ -91,20 +88,19 @@ else
 fi

 CFLAGS+=" $DEPS_INCLUDE"
-CFLAGS+=" -DROCKSDB_PLATFORM_POSIX -DROCKSDB_FALLOCATE_PRESENT -DROCKSDB_MALLOC_USABLE_SIZE"
+CFLAGS+=" -DROCKSDB_PLATFORM_POSIX -DROCKSDB_LIB_IO_POSIX -DROCKSDB_FALLOCATE_PRESENT -DROCKSDB_MALLOC_USABLE_SIZE"
 CFLAGS+=" -DSNAPPY -DGFLAGS=google -DZLIB -DBZIP2 -DLZ4 -DZSTD -DNUMA"
 CXXFLAGS+=" $CFLAGS"

-EXEC_LDFLAGS=" $SNAPPY_LIBS $ZLIB_LIBS $BZIP_LIBS $LZ4_LIBS $ZSTD_LIBS $GFLAGS_LIBS $NUMA_LIB"
+EXEC_LDFLAGS=" $SNAPPY_LIBS $ZLIB_LIBS $BZIP2_LIBS $LZ4_LIBS $ZSTD_LIBS $GFLAGS_LIBS $NUMA_LIB"
 EXEC_LDFLAGS+=" -Wl,--dynamic-linker,/usr/local/fbcode/gcc-4.8.1-glibc-2.17/lib/ld.so"
 EXEC_LDFLAGS+=" $LIBUNWIND"
 EXEC_LDFLAGS+=" -Wl,-rpath=/usr/local/fbcode/gcc-4.8.1-glibc-2.17/lib"

 PLATFORM_LDFLAGS="$LIBGCC_LIBS $GLIBC_LIBS $STDLIBS -lgcc -lstdc++"

-EXEC_LDFLAGS_SHARED="$SNAPPY_LIBS $ZLIB_LIBS $BZIP_LIBS $LZ4_LIBS $ZSTD_LIBS $GFLAGS_LIBS"
+EXEC_LDFLAGS_SHARED="$SNAPPY_LIBS $ZLIB_LIBS $BZIP2_LIBS $LZ4_LIBS $ZSTD_LIBS $GFLAGS_LIBS"

-VALGRIND_REV=b2a9f85e4b70cd03abc85a7f3027fbc4cef35bd0
-VALGRIND_VER="/mnt/gvfs/third-party2/valgrind/$VALGRIND_REV/3.8.1/gcc-4.8.1-glibc-2.17/c3f970a/bin/"
+VALGRIND_VER="$VALGRIND_BASE/bin/"

 export CC CXX AR CFLAGS CXXFLAGS EXEC_LDFLAGS EXEC_LDFLAGS_SHARED VALGRIND_VER JEMALLOC_LIB JEMALLOC_INCLUDE
@@ -243,7 +243,7 @@ make release
    --bloom_bits=10 \
    --num=$((NUM / 4)) \
    --reads=$((NUM / 4)) \
-    --writes_per_second=1000 \
+    --benchmark_write_rate_limit=$(( 110 * 1024 )) \
    --write_buffer_size=100000000 \
    --cache_size=6442450944 \
    --cache_numshardbits=6 \
@@ -329,7 +329,7 @@ common_in_mem_args="--db=/dev/shm/rocksdb \
    --use_existing_db=1 \
    --duration=600 \
    --threads=32 \
-    --writes_per_second=81920 > ${STAT_FILE}.readwhilewriting_in_ram
+    --benchmark_write_rate_limit=9502720 > ${STAT_FILE}.readwhilewriting_in_ram

 # Seekrandomwhilewriting
 ./db_bench \
@@ -342,7 +342,7 @@ common_in_mem_args="--db=/dev/shm/rocksdb \
    --use_tailing_iterator=1 \
    --duration=600 \
    --threads=32 \
-    --writes_per_second=81920 > ${STAT_FILE}.seekwhilewriting_in_ram
+    --benchmark_write_rate_limit=9502720 > ${STAT_FILE}.seekwhilewriting_in_ram

 # measure fillseq with bunch of column families
 ./db_bench \
@@ -68,6 +68,14 @@ CLANG="USE_CLANG=1"
 LITE="OPT=-DROCKSDB_LITE"
 TSAN="COMPILE_WITH_TSAN=1"
 DISABLE_JEMALLOC="DISABLE_JEMALLOC=1"
+PARSER="'parser':'egrep \'Failure|^#|Abort|Expected|Actual|GoogleTestFailure|^==\''"
+
+ARTIFACTS=" 'artifacts': [
+    {
+        'name':'database',
+        'paths':[ '/dev/shm/rocksdb' ],
+    }
+]"

 #
 # A mechanism to disable tests temporarily
@@ -100,13 +108,15 @@ PARALLEL_UNIT_TEST_COMMANDS="[
            {
                'name':'Build and test RocksDB debug version',
                'shell':'$DEBUG make -j$(nproc) all && $SHM make check > /dev/null 2>&1 || cat t/log-*',
-                'user':'root'
+                'user':'root',
+                $PARSER
            },
            $CLEANUP_ENV,
            {
                'name':'Build and test RocksDB debug version under gcc-4.8.1',
                'shell':'$GCC_481 $DEBUG make -j$(nproc) all && $SHM make check > /dev/null 2>&1 || cat t/log-*',
-                'user':'root'
+                'user':'root',
+                $PARSER
            },
        ],
        $REPORT
@@ -125,7 +135,8 @@ UNIT_TEST_COMMANDS="[
            {
                'name':'Build and test RocksDB debug version',
                'shell':'$SHM $DEBUG make J=1 check',
-                'user':'root'
+                'user':'root',
+                $PARSER
            },
        ],
        $REPORT
@@ -144,7 +155,8 @@ UNIT_TEST_COMMANDS_481="[
            {
                'name':'Build and test RocksDB debug version',
                'shell':'$SHM $GCC_481 $DEBUG make J=1 check',
-                'user':'root'
+                'user':'root',
+                $PARSER
            },
        ],
        $REPORT
@@ -163,7 +175,8 @@ CLANG_UNIT_TEST_COMMANDS="[
            {
                'name':'Build and test RocksDB debug',
                'shell':'$CLANG $SHM $DEBUG make J=1 check',
-                'user':'root'
+                'user':'root',
+                $PARSER
            },
        ],
        $REPORT
@@ -182,7 +195,8 @@ CLANG_ANALYZE_COMMANDS="[
            {
                'name':'RocksDB build and analyze',
                'shell':'$CLANG $SHM $DEBUG make J=1 analyze',
-                'user':'root'
+                'user':'root',
+                $PARSER
            },
        ],
        $REPORT
@@ -201,7 +215,8 @@ CODE_COV_COMMANDS="[
            {
                'name':'Build, test and collect code coverage info',
                'shell':'$SHM $DEBUG make J=1 coverage',
-                'user':'root'
+                'user':'root',
+                $PARSER
            },
        ],
        $REPORT
@@ -220,7 +235,8 @@ UNITY_COMMANDS="[
            {
                'name':'Build, test unity test',
                'shell':'$SHM $DEBUG V=1 make J=1 unity_test',
-                'user':'root'
+                'user':'root',
+                $PARSER
            },
        ],
        $REPORT
@@ -239,7 +255,28 @@ LITE_BUILD_COMMANDS="[
            {
                'name':'Build RocksDB debug version',
                'shell':'$LITE $DEBUG make J=1 static_lib',
-                'user':'root'
+                'user':'root',
+                $PARSER
+            },
+        ],
+        $REPORT
+    }
+]"
+
+#
+# RocksDB lite tests
+#
+LITE_UNIT_TEST_COMMANDS="[
+    {
+        'name':'Rocksdb Lite Unit Test',
+        'oncall':'$ONCALL',
+        'steps': [
+            $CLEANUP_ENV,
+            {
+                'name':'Build RocksDB debug version',
+                'shell':'$SHM $LITE $DEBUG make J=1 check',
+                'user':'root',
+                $PARSER
            },
        ],
        $REPORT
@@ -259,19 +296,44 @@ STRESS_CRASH_TEST_COMMANDS="[
            {
                'name':'Build and run RocksDB debug stress tests',
                'shell':'$SHM $DEBUG make J=1 db_stress',
-                'user':'root'
+                'user':'root',
+                $PARSER
            },
            {
                'name':'Build and run RocksDB debug crash tests',
                'timeout': 86400,
                'shell':'$SHM $DEBUG make J=1 crash_test',
-                'user':'root'
+                'user':'root',
+                $PARSER
            }
        ],
+        $ARTIFACTS,
        $REPORT
    }
 ]"

+# RocksDB write stress test.
+# We run on disk device on purpose (i.e. no $SHM)
+# because we want to add some randomness to fsync commands
+WRITE_STRESS_COMMANDS="[
+    {
+        'name':'Rocksdb Write Stress Test',
+        'oncall':'$ONCALL',
+        'steps': [
+            $CLEANUP_ENV,
+            {
+                'name':'Build and run RocksDB write stress tests',
+                'shell':'make write_stress && python tools/write_stress_runner.py --runtime_sec=3600 --db=/tmp/rocksdb_write_stress',
+                'user':'root',
+                $PARSER
+            }
+        ],
+        'artifacts': [{'name': 'database', 'paths': ['/tmp/rocksdb_write_stress']}],
+        $REPORT
+    }
+]"
+
+
 #
 # RocksDB test under address sanitizer
 #
@@ -284,7 +346,8 @@ ASAN_TEST_COMMANDS="[
            {
                'name':'Test RocksDB debug under ASAN',
                'shell':'set -o pipefail && $SHM $ASAN $DEBUG make J=1 asan_check |& /usr/facebook/ops/scripts/asan_symbolize.py -d',
-                'user':'root'
+                'user':'root',
+                $PARSER
            }
        ],
        $REPORT
@@ -305,7 +368,8 @@ ASAN_CRASH_TEST_COMMANDS="[
                'name':'Build and run RocksDB debug asan_crash_test',
                'timeout': 86400,
                'shell':'$SHM $DEBUG make J=1 asan_crash_test',
-                'user':'root'
+                'user':'root',
+                $PARSER
            },
        ],
        $REPORT
@@ -324,7 +388,8 @@ VALGRIND_TEST_COMMANDS="[
            {
                'name':'Run RocksDB debug unit tests',
                'shell':'$DISABLE_JEMALLOC $SHM $DEBUG make valgrind_check',
-                'user':'root'
+                'user':'root',
+                $PARSER
            },
        ],
        $REPORT
@@ -343,7 +408,8 @@ TSAN_UNIT_TEST_COMMANDS="[
            {
                'name':'Run RocksDB debug unit test',
                'shell':'set -o pipefail && $SHM $DEBUG $TSAN make J=1 check',
-                'user':'root'
+                'user':'root',
+                $PARSER
            },
        ],
        $REPORT
@@ -364,13 +430,16 @@ TSAN_CRASH_TEST_COMMANDS="[
                'name':'Compile and run',
                'timeout': 86400,
                'shell':'set -o pipefail && $SHM $DEBUG $TSAN make J=1 crash_test',
-                'user':'root'
+                'user':'root',
+                $PARSER
            },
        ],
        $REPORT
    }
 ]"

+TSAN_CRASH_TEST_COMMANDS=$DISABLE_COMMANDS
+
 #
 # RocksDB format compatible
 #
@@ -425,7 +494,8 @@ FORMAT_COMPATIBLE_COMMANDS="[
            {
                'name':'Run RocksDB debug unit test',
                'shell':'build_tools/rocksdb-lego-determinator run_format_compatible',
-                'user':'root'
+                'user':'root',
+                $PARSER
            },
        ],
        $REPORT
@@ -457,7 +527,8 @@ NO_COMPRESSION_COMMANDS="[
            {
                'name':'Run RocksDB debug unit test',
                'shell':'build_tools/rocksdb-lego-determinator run_no_compression',
-                'user':'root'
+                'user':'root',
+                $PARSER
            },
        ],
        $REPORT
@@ -513,7 +584,8 @@ REGRESSION_COMMANDS="[
            {
                'name':'Make and run script',
                'shell':'build_tools/rocksdb-lego-determinator run_regression',
-                'user':'root'
+                'user':'root',
+                $PARSER
            },
        ],
        $REPORT
@@ -545,9 +617,15 @@ case $1 in
  lite)
    echo $LITE_BUILD_COMMANDS
    ;;
+  lite_test)
+    echo $LITE_UNIT_TEST_COMMANDS
+    ;;
  stress_crash)
    echo $STRESS_CRASH_TEST_COMMANDS
    ;;
+  write_stress)
+    echo $WRITE_STRESS_COMMANDS
+    ;;
  asan)
    echo $ASAN_TEST_COMMANDS
    ;;
@@ -1,14 +1,19 @@
 # This script enables you running RocksDB tests by running
-# All the tests in paralell and utilizing all the cores
+# All the tests in parallel and utilizing all the cores
 # For db_test the script first lists and parses the tests
 # and then fires them up in parallel using async PS Job functionality
 # Run the script from the enlistment
 Param(
  [switch]$EnableJE = $false,  # Use je executable
+  [switch]$EnableRerun = $false, # Rerun failed tests sequentially at the end
  [string]$WorkFolder = "",  # Direct tests to use that folder
  [int]$Limit = -1, # -1 means run all otherwise limit for testing purposes
  [string]$Exclude = "", # Expect a comma separated list, no spaces
-  [string]$Run = "db_test"  # Run db_test|tests
+  [string]$Run = "db_test",  # Run db_test|tests|testname1,testname2...
+   # Number of async tasks that would run concurrently. Recommend a number below 64.
+   # However, CPU utlization really depends on the storage media. Recommend ram based disk.
+   # a value of 1 will run everything serially
+  [int]$Concurrency = 16
 )

 # Folders and commands must be fullpath to run assuming
@@ -49,7 +54,7 @@ if($EnableJE) {
 }

 Write-Output "Root: $RootFolder, WorkFolder: $WorkFolder"
-Write-Output "Binaries: $BinariesFolder exe: $db_test"
+Write-Output "Binaries: $BinariesFolder db_test: $db_test"

 #Exclusions that we do not want to run
 $ExcludeTests = New-Object System.Collections.Generic.HashSet[string]
@@ -57,7 +62,7 @@ $ExcludeTests = New-Object System.Collections.Generic.HashSet[string]

 if($Exclude -ne "") {
    Write-Host "Exclude: $Exclude"
-    $l = $Exclude -split ','
+    $l = $Exclude -split ' '
    ForEach($t in $l) { $ExcludeTests.Add($t) | Out-Null }
 }

@@ -109,38 +114,69 @@ function Normalize-DbTests($HashTable) {

        $test_log = $test -replace '[\./]','_'
        $test_log += ".log"
+        $log_path = -join ($LogFolder, $test_log)

        # Add to a hashtable
-        $HashTable.Add($test, $test_log);
+        $HashTable.Add($test, $log_path);
      }
    }
 }

+# The function removes trailing .exe siffix if any,
+# creates a name for the log file
+function MakeAndAdd([string]$token, $HashTable) {
+    $test_name = $token -replace '.exe$', ''
+    $log_name =  -join ($test_name, ".log")
+    $log_path = -join ($LogFolder, $log_name)
+    if(!$ExcludeTests.Contains($test_name)) {
+        $HashTable.Add($test_name, $log_path)
+    } else {
+        Write-Warning "Test $test_name is excluded"
+    }
+}
+
 # The function scans build\Debug folder to discover
 # Test executables. It then populates a table with
 # Test executable name -> Log file
-function Discover-TestBinaries($HashTable) {
+function Discover-TestBinaries([string]$Pattern, $HashTable) {

    $Exclusions = @("db_test*", "db_sanity_test*")
-    $p = -join ($BinariesFolder, "*_test*.exe")
+
+    $p = -join ($BinariesFolder, $pattern)
+
+    Write-Host "Path: $p"

    dir -Path $p -Exclude $Exclusions | ForEach-Object {
-       $t = ($_.Name) -replace '.exe$', ''
-       $test_log = -join ($t, ".log")
-       $HashTable.Add($t, $test_log)
+       MakeAndAdd -token ($_.Name) -HashTable $HashTable
    }
 }

-$TestToLog = [ordered]@{}
+$TestsToRun = [ordered]@{}

 if($Run -ceq "db_test") {
-    Normalize-DbTests -HashTable $TestToLog
+    Normalize-DbTests -HashTable $TestsToRun
 } elseif($Run -ceq "tests") {
-    Discover-TestBinaries -HashTable $TestToLog
+    if($EnableJE) {
+        $pattern = "*_test_je.exe"
+    } else {
+        $pattern = "*_test.exe"
+    }
+    Discover-TestBinaries -Pattern $pattern -HashTable $TestsToRun
+} else {
+
+    $test_list = $Run -split ' '
+
+    ForEach($t in $test_list) {
+       MakeAndAdd -token $t -HashTable $TestsToRun
+    }
 }

+$NumTestsToStart = $TestsToRun.Count
+if($Limit -ge 0 -and $NumTestsToStart -gt $Limit) {
+    $NumTestsToStart = $Limit
+}

-Write-Host "Attempting to start: " ($TestToLog.Count) " tests"
+Write-Host "Attempting to start: $NumTestsToStart tests"

 # Invoke a test with a filter and redirect all output
 $InvokeTestCase = {
@@ -154,93 +190,123 @@ $InvokeTestAsync = {
    &$exe > $log 2>&1
 }

-$jobs = @()
-$JobToLog = @{}
+# Hash that contains tests to rerun if any failed
+# Those tests will be rerun sequentially
+$Rerun = [ordered]@{}
 # Test limiting factor here
 $count = 0
-
-ForEach($k in $TestToLog.keys) {
-
-    Write-Host "Starting $k"
-    $log_path = -join ($LogFolder, ($TestToLog.$k))
-
-    if($Run -ceq "db_test") {
-        $job = Start-Job -Name $k -ScriptBlock $InvokeTestCase -ArgumentList @($db_test,$k,$log_path)
-    } else {
-        [string]$Exe =  -Join ($BinariesFolder, $k)
-        $job = Start-Job -Name $k -ScriptBlock $InvokeTestAsync -ArgumentList @($exe,$log_path)
-    }
-
-    $JobToLog.Add($job, $log_path)
-
-    # Limiting trial runs
-    if(($Limit -gt 0) -and (++$count -ge $Limit)) {
-         break
-    }
-}
-
+# Overall status
 [bool]$success = $true;

-# Wait for all to finish and get the results
-while($JobToLog.Count -gt 0) {
-
+function RunJobs($TestToLog, [int]$ConcurrencyVal, [bool]$AddForRerun)
+{
+    # Array to wait for any of the running jobs
    $jobs = @()
-    foreach($k in $JobToLog.Keys) { $jobs += $k }
+    # Hash JobToLog
+    $JobToLog = @{}

-<#
-    if(!$success) {
-        break
-    }
-#>
+    # Wait for all to finish and get the results
+    while(($JobToLog.Count -gt 0) -or
+          ($TestToLog.Count -gt 0)) {

-    $completed = Wait-Job -Job $jobs -Any
-    $log = $JobToLog[$completed]
-    $JobToLog.Remove($completed)
+        # Make sure we have maximum concurrent jobs running if anything
+        # and the $Limit either not set or allows to proceed
+        while(($JobToLog.Count -lt $ConcurrencyVal) -and
+              (($TestToLog.Count -gt 0) -and
+              (($Limit -lt 0) -or ($count -lt $Limit)))) {

-    $message = -join @($completed.Name, " State: ", ($completed.State))

-    $log_content = @(Get-Content $log)
-
-    if($completed.State -ne "Completed") {
-        $success = $false
-        Write-Warning $message
-        $log_content | Write-Warning
-    } else {
-        # Scan the log. If we find PASSED and no occurence of FAILED
-        # then it is a success
-        [bool]$pass_found = $false
-        ForEach($l in $log_content) {
-
-            if(($l -match "^\[\s+FAILED") -or
-               ($l -match "Assertion failed:")) {
-                $pass_found = $false
+            # We only need the first key
+            foreach($key in $TestToLog.keys) {
+                $k = $key
                break
            }

-            if(($l -match "^\[\s+PASSED") -or
-               ($l -match " : PASSED$") -or
-                ($l -match "^PASSED") -or
-                ($l -match "Passed all tests!") ) {
-                $pass_found = $true
+            Write-Host "Starting $k"
+            $log_path = ($TestToLog.$k)
+
+            if($Run -ceq "db_test") {
+              $job = Start-Job -Name $k -ScriptBlock $InvokeTestCase -ArgumentList @($db_test,$k,$log_path)
+            } else {
+              [string]$Exe =  -Join ($BinariesFolder, $k)
+               $job = Start-Job -Name $k -ScriptBlock $InvokeTestAsync -ArgumentList @($exe,$log_path)
            }
+
+            $JobToLog.Add($job, $log_path)
+            $TestToLog.Remove($k)
+
+            ++$count
        }

-        if(!$pass_found) {
-            $success = $false;
+        if($JobToLog.Count -lt 1) {
+          break
+        }
+
+        $jobs = @()
+        foreach($k in $JobToLog.Keys) { $jobs += $k }
+
+        $completed = Wait-Job -Job $jobs -Any
+        $log = $JobToLog[$completed]
+        $JobToLog.Remove($completed)
+
+        $message = -join @($completed.Name, " State: ", ($completed.State))
+
+        $log_content = @(Get-Content $log)
+
+        if($completed.State -ne "Completed") {
+            $success = $false
            Write-Warning $message
            $log_content | Write-Warning
        } else {
-            Write-Host $message
-        }
-    }
+            # Scan the log. If we find PASSED and no occurrence of FAILED
+            # then it is a success
+            [bool]$pass_found = $false
+            ForEach($l in $log_content) {

-    # Remove cached job info from the system
-    # Should be no output
-    Receive-Job -Job $completed | Out-Null
+                if(($l -match "^\[\s+FAILED") -or
+                   ($l -match "Assertion failed:")) {
+                    $pass_found = $false
+                    break
+                }
+
+                if(($l -match "^\[\s+PASSED") -or
+                   ($l -match " : PASSED$") -or
+                    ($l -match "^PASS$") -or   # Special c_test case
+                    ($l -match "Passed all tests!") ) {
+                    $pass_found = $true
+                }
+            }
+
+            if(!$pass_found) {
+                $success = $false;
+                Write-Warning $message
+                $log_content | Write-Warning
+                if($AddForRerun) {
+                    $Rerun.Add($completed.Name, $log)
+                }
+            } else {
+                Write-Host $message
+            }
+        }
+
+        # Remove cached job info from the system
+        # Should be no output
+        Receive-Job -Job $completed | Out-Null
+    }
+}
+
+RunJobs -TestToLog $TestsToRun -ConcurrencyVal $Concurrency -AddForRerun $EnableRerun
+
+if($Rerun.Count -gt 0) {
+    Write-Host "Rerunning " ($Rerun.Count) " tests sequentially"
+    $success = $true
+    $count = 0
+    RunJobs -TestToLog $Rerun -ConcurrencyVal 1 -AddForRerun $false
 }

 Get-Date

+
 if(!$success) {
 # This does not succeed killing off jobs quick
 # So we simply exit
@@ -249,4 +315,4 @@ if(!$success) {
    exit 12345
 }

- 
+ 
@@ -0,0 +1,127 @@
+#!/bin/sh
+#
+# Update dependencies.sh file with the latest avaliable versions
+
+BASEDIR=$(dirname $0)
+OUTPUT=""
+
+function log_variable()
+{
+  echo "$1=${!1}" >> "$OUTPUT"
+}
+
+
+TP2_LATEST="/mnt/vol/engshare/fbcode/third-party2"
+## $1 => lib name
+## $2 => lib version (if not provided, will try to pick latest)
+## $3 => platform (if not provided, will try to pick latest gcc)
+##
+## get_lib_base will set a variable named ${LIB_NAME}_BASE to the lib location
+function get_lib_base()
+{
+  local lib_name=$1
+  local lib_version=$2
+  local lib_platform=$3
+
+  local result="$TP2_LATEST/$lib_name/"
+  
+  # Lib Version
+  if [ -z "$lib_version" ] || [ "$lib_version" = "LATEST" ]; then
+    # version is not provided, use latest
+    result=`ls -dr1v $result/*/ | head -n1`
+  else
+    result="$result/$lib_version/"
+  fi
+  
+  # Lib Platform
+  if [ -z "$lib_platform" ]; then
+    # platform is not provided, use latest gcc
+    result=`ls -dr1v $result/gcc-*[^fb]/ | head -n1`
+  else
+    result="$result/$lib_platform/"
+  fi
+  
+  result=`ls -1d $result/*/ | head -n1`
+  
+  # lib_name => LIB_NAME_BASE
+  local __res_var=${lib_name^^}"_BASE"
+  __res_var=`echo $__res_var | tr - _`
+  # LIB_NAME_BASE=$result
+  eval $__res_var=`readlink -f $result`
+  
+  log_variable $__res_var
+}
+
+###########################################################
+#                   4.9.x dependencies                    #
+###########################################################
+
+OUTPUT="$BASEDIR/dependencies.sh"
+
+rm -f "$OUTPUT"
+touch "$OUTPUT"
+
+echo "Writing dependencies to $OUTPUT"
+
+# Compilers locations
+GCC_BASE=`ls -d1 $TP2_LATEST/gcc/4.9.x/centos6-native/*/ | head -n1`
+CLANG_BASE=`ls -d1 $TP2_LATEST/clang/3.7.1/centos6-native/*/ | head -n1`
+
+log_variable GCC_BASE
+log_variable CLANG_BASE
+
+# Libraries locations
+get_lib_base libgcc     4.9.x
+get_lib_base glibc      2.20 
+get_lib_base snappy     LATEST
+get_lib_base zlib       LATEST
+get_lib_base bzip2      LATEST
+get_lib_base lz4        LATEST
+get_lib_base zstd       LATEST
+get_lib_base gflags     LATEST
+get_lib_base jemalloc   LATEST
+get_lib_base numa       LATEST
+get_lib_base libunwind  LATEST
+
+get_lib_base kernel-headers LATEST 
+get_lib_base binutils   LATEST centos6-native 
+get_lib_base valgrind   LATEST
+
+git diff $OUTPUT
+
+###########################################################
+#                   4.8.1 dependencies                    #
+###########################################################
+
+OUTPUT="$BASEDIR/dependencies_4.8.1.sh"
+
+rm -f "$OUTPUT"
+touch "$OUTPUT"
+
+echo "Writing 4.8.1 dependencies to $OUTPUT"
+
+# Compilers locations
+GCC_BASE=`ls -d1 $TP2_LATEST/gcc/4.8.1/centos6-native/*/ | head -n1`
+CLANG_BASE=`ls -d1 $TP2_LATEST/clang/3.7.1/centos6-native/*/ | head -n1`
+
+log_variable GCC_BASE
+log_variable CLANG_BASE
+
+# Libraries locations
+get_lib_base libgcc     4.8.1  gcc-4.8.1-glibc-2.17
+get_lib_base glibc      2.17   gcc-4.8.1-glibc-2.17  
+get_lib_base snappy     LATEST gcc-4.8.1-glibc-2.17
+get_lib_base zlib       LATEST gcc-4.8.1-glibc-2.17
+get_lib_base bzip2      LATEST gcc-4.8.1-glibc-2.17
+get_lib_base lz4        LATEST gcc-4.8.1-glibc-2.17
+get_lib_base zstd       LATEST gcc-4.8.1-glibc-2.17
+get_lib_base gflags     LATEST gcc-4.8.1-glibc-2.17
+get_lib_base jemalloc   LATEST gcc-4.8.1-glibc-2.17
+get_lib_base numa       LATEST gcc-4.8.1-glibc-2.17
+get_lib_base libunwind  LATEST gcc-4.8.1-glibc-2.17
+
+get_lib_base kernel-headers LATEST gcc-4.8.1-glibc-2.17 
+get_lib_base binutils   LATEST centos6-native 
+get_lib_base valgrind   3.8.1  gcc-4.8.1-glibc-2.17
+
+git diff $OUTPUT
@@ -26,6 +26,7 @@
 #include "rocksdb/options.h"
 #include "rocksdb/table.h"
 #include "table/block_based_table_builder.h"
+#include "table/internal_iterator.h"
 #include "util/file_reader_writer.h"
 #include "util/iostats_context_imp.h"
 #include "util/stop_watch.h"
@@ -40,22 +41,26 @@ TableBuilder* NewTableBuilder(
    const InternalKeyComparator& internal_comparator,
    const std::vector<std::unique_ptr<IntTblPropCollectorFactory>>*
        int_tbl_prop_collector_factories,
-    WritableFileWriter* file, const CompressionType compression_type,
+    uint32_t column_family_id, WritableFileWriter* file,
+    const CompressionType compression_type,
    const CompressionOptions& compression_opts, const bool skip_filters) {
  return ioptions.table_factory->NewTableBuilder(
      TableBuilderOptions(ioptions, internal_comparator,
                          int_tbl_prop_collector_factories, compression_type,
                          compression_opts, skip_filters),
-      file);
+      column_family_id, file);
 }

 Status BuildTable(
    const std::string& dbname, Env* env, const ImmutableCFOptions& ioptions,
-    const EnvOptions& env_options, TableCache* table_cache, Iterator* iter,
-    FileMetaData* meta, const InternalKeyComparator& internal_comparator,
+    const EnvOptions& env_options, TableCache* table_cache,
+    InternalIterator* iter, FileMetaData* meta,
+    const InternalKeyComparator& internal_comparator,
    const std::vector<std::unique_ptr<IntTblPropCollectorFactory>>*
        int_tbl_prop_collector_factories,
-    std::vector<SequenceNumber> snapshots, const CompressionType compression,
+    uint32_t column_family_id, std::vector<SequenceNumber> snapshots,
+    SequenceNumber earliest_write_conflict_snapshot,
+    const CompressionType compression,
    const CompressionOptions& compression_opts, bool paranoid_file_checks,
    InternalStats* internal_stats, const Env::IOPriority io_priority,
    TableProperties* table_properties) {
@@ -72,7 +77,7 @@ Status BuildTable(
    unique_ptr<WritableFileWriter> file_writer;
    {
      unique_ptr<WritableFile> file;
-      s = env->NewWritableFile(fname, &file, env_options);
+      s = NewWritableFile(env, fname, &file, env_options);
      if (!s.ok()) {
        return s;
      }
@@ -82,7 +87,7 @@ Status BuildTable(

      builder = NewTableBuilder(
          ioptions, internal_comparator, int_tbl_prop_collector_factories,
-          file_writer.get(), compression, compression_opts);
+          column_family_id, file_writer.get(), compression, compression_opts);
    }

    MergeHelper merge(env, internal_comparator.user_comparator(),
@@ -92,7 +97,8 @@ Status BuildTable(
                      snapshots.empty() ? 0 : snapshots.back());

    CompactionIterator c_iter(iter, internal_comparator.user_comparator(),
-                              &merge, kMaxSequenceNumber, &snapshots, env,
+                              &merge, kMaxSequenceNumber, &snapshots,
+                              earliest_write_conflict_snapshot, env,
                              true /* internal key corruption is not ok */);
    c_iter.SeekToFirst();
    for (; c_iter.Valid(); c_iter.Next()) {
@@ -139,7 +145,7 @@ Status BuildTable(

    if (s.ok() && !empty) {
      // Verify that the table is usable
-      std::unique_ptr<Iterator> it(table_cache->NewIterator(
+      std::unique_ptr<InternalIterator> it(table_cache->NewIterator(
          ReadOptions(), env_options, internal_comparator, meta->fd, nullptr,
          (internal_stats == nullptr) ? nullptr
                                      : internal_stats->GetFileReadHist(0),
@@ -31,13 +31,15 @@ class VersionEdit;
 class TableBuilder;
 class WritableFileWriter;
 class InternalStats;
+class InternalIterator;

 TableBuilder* NewTableBuilder(
    const ImmutableCFOptions& options,
    const InternalKeyComparator& internal_comparator,
    const std::vector<std::unique_ptr<IntTblPropCollectorFactory>>*
        int_tbl_prop_collector_factories,
-    WritableFileWriter* file, const CompressionType compression_type,
+    uint32_t column_family_id, WritableFileWriter* file,
+    const CompressionType compression_type,
    const CompressionOptions& compression_opts,
    const bool skip_filters = false);

@@ -48,11 +50,14 @@ TableBuilder* NewTableBuilder(
 // zero, and no Table file will be produced.
 extern Status BuildTable(
    const std::string& dbname, Env* env, const ImmutableCFOptions& options,
-    const EnvOptions& env_options, TableCache* table_cache, Iterator* iter,
-    FileMetaData* meta, const InternalKeyComparator& internal_comparator,
+    const EnvOptions& env_options, TableCache* table_cache,
+    InternalIterator* iter, FileMetaData* meta,
+    const InternalKeyComparator& internal_comparator,
    const std::vector<std::unique_ptr<IntTblPropCollectorFactory>>*
        int_tbl_prop_collector_factories,
-    std::vector<SequenceNumber> snapshots, const CompressionType compression,
+    uint32_t column_family_id, std::vector<SequenceNumber> snapshots,
+    SequenceNumber earliest_write_conflict_snapshot,
+    const CompressionType compression,
    const CompressionOptions& compression_opts, bool paranoid_file_checks,
    InternalStats* internal_stats,
    const Env::IOPriority io_priority = Env::IO_HIGH,
@@ -1288,6 +1288,11 @@ void rocksdb_block_based_options_set_cache_index_and_filter_blocks(
  options->rep.cache_index_and_filter_blocks = v;
 }

+void rocksdb_block_based_options_set_skip_table_builder_flush(
+    rocksdb_block_based_table_options_t* options, unsigned char v) {
+  options->rep.skip_table_builder_flush = v;
+}
+
 void rocksdb_options_set_block_based_table_factory(
    rocksdb_options_t *opt,
    rocksdb_block_based_table_options_t* table_options) {
@@ -1687,6 +1692,11 @@ void rocksdb_options_set_keep_log_file_num(rocksdb_options_t* opt, size_t v) {
  opt->rep.keep_log_file_num = v;
 }

+void rocksdb_options_set_recycle_log_file_num(rocksdb_options_t* opt,
+                                              size_t v) {
+  opt->rep.recycle_log_file_num = v;
+}
+
 void rocksdb_options_set_soft_rate_limit(rocksdb_options_t* opt, double v) {
  opt->rep.soft_rate_limit = v;
 }
@@ -1756,6 +1766,11 @@ void rocksdb_options_set_memtable_prefix_bloom_probes(
  opt->rep.memtable_prefix_bloom_probes = v;
 }

+void rocksdb_options_set_memtable_prefix_bloom_huge_page_tlb_size(
+    rocksdb_options_t* opt, size_t v) {
+  opt->rep.memtable_prefix_bloom_huge_page_tlb_size = v;
+}
+
 void rocksdb_options_set_hash_skip_list_rep(
    rocksdb_options_t *opt, size_t bucket_count,
    int32_t skiplist_height, int32_t skiplist_branching_factor) {
@@ -1955,7 +1970,7 @@ void rocksdb_filterpolicy_destroy(rocksdb_filterpolicy_t* filter) {
  delete filter;
 }

-rocksdb_filterpolicy_t* rocksdb_filterpolicy_create_bloom(int bits_per_key) {
+rocksdb_filterpolicy_t* rocksdb_filterpolicy_create_bloom_format(int bits_per_key, bool original_format) {
  // Make a rocksdb_filterpolicy_t, but override all of its methods so
  // they delegate to a NewBloomFilterPolicy() instead of user
  // supplied C functions.
@@ -1973,13 +1988,21 @@ rocksdb_filterpolicy_t* rocksdb_filterpolicy_create_bloom(int bits_per_key) {
    static void DoNothing(void*) { }
  };
  Wrapper* wrapper = new Wrapper;
-  wrapper->rep_ = NewBloomFilterPolicy(bits_per_key);
+  wrapper->rep_ = NewBloomFilterPolicy(bits_per_key, original_format);
  wrapper->state_ = nullptr;
  wrapper->delete_filter_ = nullptr;
  wrapper->destructor_ = &Wrapper::DoNothing;
  return wrapper;
 }

+rocksdb_filterpolicy_t* rocksdb_filterpolicy_create_bloom_full(int bits_per_key) {
+  return rocksdb_filterpolicy_create_bloom_format(bits_per_key, false);
+}
+
+rocksdb_filterpolicy_t* rocksdb_filterpolicy_create_bloom(int bits_per_key) {
+  return rocksdb_filterpolicy_create_bloom_format(bits_per_key, true);
+}
+
 rocksdb_mergeoperator_t* rocksdb_mergeoperator_create(
    void* state, void (*destructor)(void*),
    char* (*full_merge)(void*, const char* key, size_t key_length,
@@ -27,9 +27,9 @@
 #include "db/version_set.h"
 #include "db/write_controller.h"
 #include "db/writebuffer.h"
+#include "memtable/hash_skiplist_rep.h"
 #include "util/autovector.h"
 #include "util/compression.h"
-#include "util/hash_skiplist_rep.h"
 #include "util/options_helper.h"
 #include "util/thread_status_util.h"
 #include "util/xfunc.h"
@@ -68,6 +68,20 @@ const std::string& ColumnFamilyHandleImpl::GetName() const {
  return cfd()->GetName();
 }

+Status ColumnFamilyHandleImpl::GetDescriptor(ColumnFamilyDescriptor* desc) {
+#ifndef ROCKSDB_LITE
+  // accessing mutable cf-options requires db mutex.
+  InstrumentedMutexLock l(mutex_);
+  *desc = ColumnFamilyDescriptor(
+      cfd()->GetName(),
+      BuildColumnFamilyOptions(*cfd()->options(),
+                               *cfd()->GetLatestMutableCFOptions()));
+  return Status::OK();
+#else
+  return Status::NotSupported();
+#endif  // !ROCKSDB_LITE
+}
+
 const Comparator* ColumnFamilyHandleImpl::user_comparator() const {
  return cfd()->user_comparator();
 }
@@ -110,6 +124,24 @@ Status CheckCompressionSupported(const ColumnFamilyOptions& cf_options) {
  return Status::OK();
 }

+Status CheckConcurrentWritesSupported(const ColumnFamilyOptions& cf_options) {
+  if (cf_options.inplace_update_support) {
+    return Status::InvalidArgument(
+        "In-place memtable updates (inplace_update_support) is not compatible "
+        "with concurrent writes (allow_concurrent_memtable_write)");
+  }
+  if (cf_options.filter_deletes) {
+    return Status::InvalidArgument(
+        "Delete filtering (filter_deletes) is not compatible with concurrent "
+        "memtable writes (allow_concurrent_memtable_writes)");
+  }
+  if (!cf_options.memtable_factory->IsInsertConcurrentlySupported()) {
+    return Status::InvalidArgument(
+        "Memtable doesn't concurrent writes (allow_concurrent_memtable_write)");
+  }
+  return Status::OK();
+}
+
 ColumnFamilyOptions SanitizeOptions(const DBOptions& db_options,
                                    const InternalKeyComparator* icmp,
                                    const ColumnFamilyOptions& src) {
@@ -175,6 +207,12 @@ ColumnFamilyOptions SanitizeOptions(const DBOptions& db_options,
    result.level0_stop_writes_trigger = std::numeric_limits<int>::max();
  }

+  if (result.level0_file_num_compaction_trigger == 0) {
+    Warn(db_options.info_log.get(),
+         "level0_file_num_compaction_trigger cannot be 0");
+    result.level0_file_num_compaction_trigger = 1;
+  }
+
  if (result.level0_stop_writes_trigger <
          result.level0_slowdown_writes_trigger ||
      result.level0_slowdown_writes_trigger <
@@ -309,7 +347,8 @@ ColumnFamilyData::ColumnFamilyData(
      log_number_(0),
      column_family_set_(column_family_set),
      pending_flush_(false),
-      pending_compaction_(false) {
+      pending_compaction_(false),
+      prev_compaction_needed_bytes_(0) {
  Ref();

  // Convert user defined table properties collector factories to internal ones.
@@ -427,13 +466,66 @@ void ColumnFamilyData::SetDropped() {
  column_family_set_->RemoveColumnFamily(this);
 }

+const double kSlowdownRatio = 1.2;
+
+namespace {
+std::unique_ptr<WriteControllerToken> SetupDelay(
+    uint64_t max_write_rate, WriteController* write_controller,
+    uint64_t compaction_needed_bytes, uint64_t prev_compaction_neeed_bytes,
+    bool auto_comapctions_disabled) {
+  const uint64_t kMinWriteRate = 1024u;  // Minimum write rate 1KB/s.
+
+  uint64_t write_rate = write_controller->delayed_write_rate();
+
+  if (auto_comapctions_disabled) {
+    // When auto compaction is disabled, always use the value user gave.
+    write_rate = max_write_rate;
+  } else if (write_controller->NeedsDelay() && max_write_rate > kMinWriteRate) {
+    // If user gives rate less than kMinWriteRate, don't adjust it.
+    //
+    // If already delayed, need to adjust based on previous compaction debt.
+    // When there are two or more column families require delay, we always
+    // increase or reduce write rate based on information for one single
+    // column family. It is likely to be OK but we can improve if there is a
+    // problem.
+    // Ignore compaction_needed_bytes = 0 case because compaction_needed_bytes
+    // is only available in level-based compaction
+    //
+    // If the compaction debt stays the same as previously, we also further slow
+    // down. It usually means a mem table is full. It's mainly for the case
+    // where both of flush and compaction are much slower than the speed we
+    // insert to mem tables, so we need to actively slow down before we get
+    // feedback signal from compaction and flushes to avoid the full stop
+    // because of hitting the max write buffer number.
+    if (prev_compaction_neeed_bytes > 0 &&
+        prev_compaction_neeed_bytes <= compaction_needed_bytes) {
+      write_rate = static_cast<uint64_t>(static_cast<double>(write_rate) /
+                                         kSlowdownRatio);
+      if (write_rate < kMinWriteRate) {
+        write_rate = kMinWriteRate;
+      }
+    } else if (prev_compaction_neeed_bytes > compaction_needed_bytes) {
+      // We are speeding up by ratio of kSlowdownRatio when we have paid
+      // compaction debt. But we'll never speed up to faster than the write rate
+      // given by users.
+      write_rate = static_cast<uint64_t>(static_cast<double>(write_rate) *
+                                         kSlowdownRatio);
+      if (write_rate > max_write_rate) {
+        write_rate = max_write_rate;
+      }
+    }
+  }
+  return write_controller->GetDelayToken(write_rate);
+}
+}  // namespace
+
 void ColumnFamilyData::RecalculateWriteStallConditions(
      const MutableCFOptions& mutable_cf_options) {
  if (current_ != nullptr) {
    auto* vstorage = current_->storage_info();
-    const double score = vstorage->max_compaction_score();
-    const int max_level = vstorage->max_compaction_score_level();
    auto write_controller = column_family_set_->write_controller_;
+    uint64_t compaction_needed_bytes =
+        vstorage->estimated_compaction_needed_bytes();

    if (imm()->NumNotFlushed() >= mutable_cf_options.max_write_buffer_number) {
      write_controller_token_ = write_controller->GetStopToken();
@@ -443,6 +535,21 @@ void ColumnFamilyData::RecalculateWriteStallConditions(
          "(waiting for flush), max_write_buffer_number is set to %d",
          name_.c_str(), imm()->NumNotFlushed(),
          mutable_cf_options.max_write_buffer_number);
+    } else if (mutable_cf_options.max_write_buffer_number > 3 &&
+               imm()->NumNotFlushed() >=
+                   mutable_cf_options.max_write_buffer_number - 1) {
+      write_controller_token_ =
+          SetupDelay(ioptions_.delayed_write_rate, write_controller,
+                     compaction_needed_bytes, prev_compaction_needed_bytes_,
+                     mutable_cf_options.disable_auto_compactions);
+      internal_stats_->AddCFStats(InternalStats::MEMTABLE_SLOWDOWN, 1);
+      Log(InfoLogLevel::WARN_LEVEL, ioptions_.info_log,
+          "[%s] Stalling writes because we have %d immutable memtables "
+          "(waiting for flush), max_write_buffer_number is set to %d "
+          "rate %" PRIu64,
+          name_.c_str(), imm()->NumNotFlushed(),
+          mutable_cf_options.max_write_buffer_number,
+          write_controller->delayed_write_rate());
    } else if (vstorage->l0_delay_trigger_count() >=
               mutable_cf_options.level0_stop_writes_trigger) {
      write_controller_token_ = write_controller->GetStopToken();
@@ -455,37 +562,50 @@ void ColumnFamilyData::RecalculateWriteStallConditions(
          "[%s] Stopping writes because we have %d level-0 files",
          name_.c_str(), vstorage->l0_delay_trigger_count());
    } else if (mutable_cf_options.hard_pending_compaction_bytes_limit > 0 &&
-               vstorage->estimated_compaction_needed_bytes() >=
+               compaction_needed_bytes >=
                   mutable_cf_options.hard_pending_compaction_bytes_limit) {
      write_controller_token_ = write_controller->GetStopToken();
      internal_stats_->AddCFStats(
          InternalStats::HARD_PENDING_COMPACTION_BYTES_LIMIT, 1);
      Log(InfoLogLevel::WARN_LEVEL, ioptions_.info_log,
-          "[%s] Stopping writes because estimated pending compaction "
-          "bytes exceed %" PRIu64,
-          name_.c_str(), vstorage->estimated_compaction_needed_bytes());
+          "[%s] Stopping writes because of estimated pending compaction "
+          "bytes %" PRIu64,
+          name_.c_str(), compaction_needed_bytes);
    } else if (mutable_cf_options.level0_slowdown_writes_trigger >= 0 &&
               vstorage->l0_delay_trigger_count() >=
                   mutable_cf_options.level0_slowdown_writes_trigger) {
-      write_controller_token_ = write_controller->GetDelayToken();
+      write_controller_token_ =
+          SetupDelay(ioptions_.delayed_write_rate, write_controller,
+                     compaction_needed_bytes, prev_compaction_needed_bytes_,
+                     mutable_cf_options.disable_auto_compactions);
      internal_stats_->AddCFStats(InternalStats::LEVEL0_SLOWDOWN_TOTAL, 1);
      if (compaction_picker_->IsLevel0CompactionInProgress()) {
        internal_stats_->AddCFStats(
            InternalStats::LEVEL0_SLOWDOWN_WITH_COMPACTION, 1);
      }
      Log(InfoLogLevel::WARN_LEVEL, ioptions_.info_log,
-          "[%s] Stalling writes because we have %d level-0 files",
-          name_.c_str(), vstorage->l0_delay_trigger_count());
-    } else if (mutable_cf_options.soft_rate_limit > 0.0 &&
-               score > mutable_cf_options.soft_rate_limit) {
-      write_controller_token_ = write_controller->GetDelayToken();
-      internal_stats_->RecordLevelNSlowdown(max_level, true);
+          "[%s] Stalling writes because we have %d level-0 files "
+          "rate %" PRIu64,
+          name_.c_str(), vstorage->l0_delay_trigger_count(),
+          write_controller->delayed_write_rate());
+    } else if (mutable_cf_options.soft_pending_compaction_bytes_limit > 0 &&
+               vstorage->estimated_compaction_needed_bytes() >=
+                   mutable_cf_options.soft_pending_compaction_bytes_limit) {
+      write_controller_token_ =
+          SetupDelay(ioptions_.delayed_write_rate, write_controller,
+                     compaction_needed_bytes, prev_compaction_needed_bytes_,
+                     mutable_cf_options.disable_auto_compactions);
+      internal_stats_->AddCFStats(
+          InternalStats::SOFT_PENDING_COMPACTION_BYTES_LIMIT, 1);
      Log(InfoLogLevel::WARN_LEVEL, ioptions_.info_log,
-          "[%s] Stalling writes because we hit soft limit on level %d",
-          name_.c_str(), max_level);
+          "[%s] Stalling writes because of estimated pending compaction "
+          "bytes %" PRIu64 " rate %" PRIu64,
+          name_.c_str(), vstorage->estimated_compaction_needed_bytes(),
+          write_controller->delayed_write_rate());
    } else {
      write_controller_token_.reset();
    }
+    prev_compaction_needed_bytes_ = compaction_needed_bytes;
  }
 }

@@ -539,13 +659,12 @@ const int ColumnFamilyData::kCompactAllLevels = -1;
 const int ColumnFamilyData::kCompactToBaseLevel = -2;

 Compaction* ColumnFamilyData::CompactRange(
-    const MutableCFOptions& mutable_cf_options,
-    int input_level, int output_level, uint32_t output_path_id,
-    const InternalKey* begin, const InternalKey* end,
-    InternalKey** compaction_end) {
+    const MutableCFOptions& mutable_cf_options, int input_level,
+    int output_level, uint32_t output_path_id, const InternalKey* begin,
+    const InternalKey* end, InternalKey** compaction_end, bool* conflict) {
  auto* result = compaction_picker_->CompactRange(
      GetName(), mutable_cf_options, current_->storage_info(), input_level,
-      output_level, output_path_id, begin, end, compaction_end);
+      output_level, output_path_id, begin, end, compaction_end, conflict);
  if (result != nullptr) {
    result->SetInputVersion(current_);
  }
@@ -831,13 +950,6 @@ ColumnFamilyHandle* ColumnFamilyMemTablesImpl::GetColumnFamilyHandle() {
  return &handle_;
 }

-void ColumnFamilyMemTablesImpl::CheckMemtableFull() {
-  if (current_ != nullptr && current_->mem()->ShouldScheduleFlush()) {
-    flush_scheduler_->ScheduleFlush(current_);
-    current_->mem()->MarkFlushScheduled();
-  }
-}
-
 uint32_t GetColumnFamilyID(ColumnFamilyHandle* column_family) {
  uint32_t column_family_id = 0;
  if (column_family != nullptr) {
@@ -19,12 +19,10 @@
 #include "db/write_controller.h"
 #include "db/table_cache.h"
 #include "db/table_properties_collector.h"
-#include "db/flush_scheduler.h"
 #include "rocksdb/compaction_job_stats.h"
 #include "rocksdb/db.h"
 #include "rocksdb/env.h"
 #include "rocksdb/options.h"
-#include "util/instrumented_mutex.h"
 #include "util/mutable_cf_options.h"
 #include "util/thread_local.h"

@@ -44,6 +42,8 @@ class LogBuffer;
 class InstrumentedMutex;
 class InstrumentedMutexLock;

+extern const double kSlowdownRatio;
+
 // ColumnFamilyHandleImpl is the class that clients use to access different
 // column families. It has non-trivial destructor, which gets called when client
 // is done using the column family
@@ -59,6 +59,7 @@ class ColumnFamilyHandleImpl : public ColumnFamilyHandle {

  virtual uint32_t GetID() const override;
  virtual const std::string& GetName() const override;
+  virtual Status GetDescriptor(ColumnFamilyDescriptor* desc) override;

 private:
  ColumnFamilyData* cfd_;
@@ -132,6 +133,9 @@ struct SuperVersion {

 extern Status CheckCompressionSupported(const ColumnFamilyOptions& cf_options);

+extern Status CheckConcurrentWritesSupported(
+    const ColumnFamilyOptions& cf_options);
+
 extern ColumnFamilyOptions SanitizeOptions(const DBOptions& db_options,
                                           const InternalKeyComparator* icmp,
                                           const ColumnFamilyOptions& src);
@@ -156,14 +160,16 @@ class ColumnFamilyData {
  // thread-safe
  const std::string& GetName() const { return name_; }

-  // Ref() can only be called whily holding a DB mutex or during a
-  // single-threaded write.
+  // Ref() can only be called from a context where the caller can guarantee
+  // that ColumnFamilyData is alive (while holding a non-zero ref already,
+  // holding a DB mutex, or as the leader in a write batch group).
  void Ref() { refs_.fetch_add(1, std::memory_order_relaxed); }
-  // will just decrease reference count to 0, but will not delete it. returns
-  // true if the ref count was decreased to zero. in that case, it can be
-  // deleted by the caller immediately, or later, by calling
-  // FreeDeadColumnFamilies()
-  // Unref() can only be called while holding a DB mutex
+
+  // Unref decreases the reference count, but does not handle deletion
+  // when the count goes to 0.  If this method returns true then the
+  // caller should delete the instance immediately, or later, by calling
+  // FreeDeadColumnFamilies().  Unref() can only be called while holding
+  // a DB mutex, or during single-threaded recovery.
  bool Unref() {
    int old_refs = refs_.fetch_sub(1, std::memory_order_relaxed);
    assert(old_refs > 0);
@@ -224,7 +230,7 @@ class ColumnFamilyData {
  MemTable* mem() { return mem_; }
  Version* current() { return current_; }
  Version* dummy_versions() { return dummy_versions_; }
-  void SetCurrent(Version* current);
+  void SetCurrent(Version* _current);
  uint64_t GetNumLiveVersions() const;  // REQUIRE: DB mutex held
  uint64_t GetTotalSstFilesSize() const;  // REQUIRE: DB mutex held
  void SetMemtable(MemTable* new_mem) { mem_ = new_mem; }
@@ -249,11 +255,11 @@ class ColumnFamilyData {
  // A flag to tell a manual compaction's output is base level.
  static const int kCompactToBaseLevel;
  // REQUIRES: DB mutex held
-  Compaction* CompactRange(
-      const MutableCFOptions& mutable_cf_options,
-      int input_level, int output_level, uint32_t output_path_id,
-      const InternalKey* begin, const InternalKey* end,
-      InternalKey** compaction_end);
+  Compaction* CompactRange(const MutableCFOptions& mutable_cf_options,
+                           int input_level, int output_level,
+                           uint32_t output_path_id, const InternalKey* begin,
+                           const InternalKey* end, InternalKey** compaction_end,
+                           bool* manual_conflict);

  CompactionPicker* compaction_picker() { return compaction_picker_.get(); }
  // thread-safe
@@ -305,6 +311,14 @@ class ColumnFamilyData {
  bool pending_flush() { return pending_flush_; }
  bool pending_compaction() { return pending_compaction_; }

+  // Recalculate some small conditions, which are changed only during
+  // compaction, adding new memtable and/or
+  // recalculation of compaction score. These values are used in
+  // DBImpl::MakeRoomForWrite function to decide, if it need to make
+  // a write stall
+  void RecalculateWriteStallConditions(
+      const MutableCFOptions& mutable_cf_options);
+
 private:
  friend class ColumnFamilySet;
  ColumnFamilyData(uint32_t id, const std::string& name,
@@ -314,14 +328,6 @@ class ColumnFamilyData {
                   const DBOptions* db_options, const EnvOptions& env_options,
                   ColumnFamilySet* column_family_set);

-  // Recalculate some small conditions, which are changed only during
-  // compaction, adding new memtable and/or
-  // recalculation of compaction score. These values are used in
-  // DBImpl::MakeRoomForWrite function to decide, if it need to make
-  // a write stall
-  void RecalculateWriteStallConditions(
-      const MutableCFOptions& mutable_cf_options);
-
  uint32_t id_;
  const std::string name_;
  Version* dummy_versions_;  // Head of circular doubly-linked list of versions.
@@ -382,6 +388,8 @@ class ColumnFamilyData {
  // If true --> this ColumnFamily is currently present in
  // DBImpl::compaction_queue_
  bool pending_compaction_;
+
+  uint64_t prev_compaction_needed_bytes_;
 };

 // ColumnFamilySet has interesting thread-safety requirements
@@ -493,15 +501,18 @@ class ColumnFamilySet {
 // memtables of different column families (specified by ID in the write batch)
 class ColumnFamilyMemTablesImpl : public ColumnFamilyMemTables {
 public:
-  explicit ColumnFamilyMemTablesImpl(ColumnFamilySet* column_family_set,
-                                     FlushScheduler* flush_scheduler)
-      : column_family_set_(column_family_set),
-        current_(nullptr),
-        flush_scheduler_(flush_scheduler) {}
+  explicit ColumnFamilyMemTablesImpl(ColumnFamilySet* column_family_set)
+      : column_family_set_(column_family_set), current_(nullptr) {}
+
+  // Constructs a ColumnFamilyMemTablesImpl equivalent to one constructed
+  // with the arguments used to construct *orig.
+  explicit ColumnFamilyMemTablesImpl(ColumnFamilyMemTablesImpl* orig)
+      : column_family_set_(orig->column_family_set_), current_(nullptr) {}

  // sets current_ to ColumnFamilyData with column_family_id
  // returns false if column family doesn't exist
-  // REQUIRES: under a DB mutex OR from a write thread
+  // REQUIRES: use this function of DBImpl::column_family_memtables_ should be
+  //           under a DB mutex OR from a write thread
  bool Seek(uint32_t column_family_id) override;

  // Returns log number of the selected column family
@@ -509,20 +520,23 @@ class ColumnFamilyMemTablesImpl : public ColumnFamilyMemTables {
  uint64_t GetLogNumber() const override;

  // REQUIRES: Seek() called first
-  // REQUIRES: under a DB mutex OR from a write thread
+  // REQUIRES: use this function of DBImpl::column_family_memtables_ should be
+  //           under a DB mutex OR from a write thread
  virtual MemTable* GetMemTable() const override;

  // Returns column family handle for the selected column family
-  // REQUIRES: under a DB mutex OR from a write thread
+  // REQUIRES: use this function of DBImpl::column_family_memtables_ should be
+  //           under a DB mutex OR from a write thread
  virtual ColumnFamilyHandle* GetColumnFamilyHandle() override;

-  // REQUIRES: under a DB mutex OR from a write thread
-  virtual void CheckMemtableFull() override;
+  // Cannot be called while another thread is calling Seek().
+  // REQUIRES: use this function of DBImpl::column_family_memtables_ should be
+  //           under a DB mutex OR from a write thread
+  virtual ColumnFamilyData* current() override { return current_; }

 private:
  ColumnFamilySet* column_family_set_;
  ColumnFamilyData* current_;
-  FlushScheduler* flush_scheduler_;
  ColumnFamilyHandleInternal handle_;
 };

@@ -12,6 +12,7 @@
 #include "rocksdb/db.h"
 #include "rocksdb/env.h"
 #include "util/string_util.h"
+#include "util/sync_point.h"
 #include "util/testharness.h"

 namespace rocksdb {
@@ -53,6 +54,63 @@ class FlushedFileCollector : public EventListener {
  std::mutex mutex_;
 };

+TEST_F(CompactFilesTest, L0ConflictsFiles) {
+  Options options;
+  // to trigger compaction more easily
+  const int kWriteBufferSize = 10000;
+  const int kLevel0Trigger = 2;
+  options.create_if_missing = true;
+  options.compaction_style = kCompactionStyleLevel;
+  // Small slowdown and stop trigger for experimental purpose.
+  options.level0_slowdown_writes_trigger = 20;
+  options.level0_stop_writes_trigger = 20;
+  options.level0_stop_writes_trigger = 20;
+  options.write_buffer_size = kWriteBufferSize;
+  options.level0_file_num_compaction_trigger = kLevel0Trigger;
+  options.compression = kNoCompression;
+
+  DB* db = nullptr;
+  DestroyDB(db_name_, options);
+  Status s = DB::Open(options, db_name_, &db);
+  assert(s.ok());
+  assert(db);
+
+  rocksdb::SyncPoint::GetInstance()->LoadDependency({
+      {"CompactFilesImpl:0", "BackgroundCallCompaction:0"},
+      {"BackgroundCallCompaction:1", "CompactFilesImpl:1"},
+  });
+  rocksdb::SyncPoint::GetInstance()->EnableProcessing();
+
+  // create couple files
+  // Background compaction starts and waits in BackgroundCallCompaction:0
+  for (int i = 0; i < kLevel0Trigger * 4; ++i) {
+    db->Put(WriteOptions(), ToString(i), "");
+    db->Put(WriteOptions(), ToString(100 - i), "");
+    db->Flush(FlushOptions());
+  }
+
+  rocksdb::ColumnFamilyMetaData meta;
+  db->GetColumnFamilyMetaData(&meta);
+  std::string file1;
+  for (auto& file : meta.levels[0].files) {
+    ASSERT_EQ(0, meta.levels[0].level);
+    if (file1 == "") {
+      file1 = file.db_path + "/" + file.name;
+    } else {
+      std::string file2 = file.db_path + "/" + file.name;
+      // Another thread starts a compact files and creates an L0 compaction
+      // The background compaction then notices that there is an L0 compaction
+      // already in progress and doesn't do an L0 compaction
+      // Once the background compaction finishes, the compact files finishes
+      ASSERT_OK(
+          db->CompactFiles(rocksdb::CompactionOptions(), {file1, file2}, 0));
+      break;
+    }
+  }
+  rocksdb::SyncPoint::GetInstance()->DisableProcessing();
+  delete db;
+}
+
 TEST_F(CompactFilesTest, ObsoleteFiles) {
  Options options;
  // to trigger compaction more easily
@@ -46,7 +46,7 @@ void Compaction::GetBoundaryKeys(
    Slice* largest_user_key) {
  bool initialized = false;
  const Comparator* ucmp = vstorage->InternalComparator()->user_comparator();
-  for (uint32_t i = 0; i < inputs.size(); ++i) {
+  for (size_t i = 0; i < inputs.size(); ++i) {
    if (inputs[i].files.empty()) {
      continue;
    }
@@ -128,8 +128,8 @@ bool Compaction::TEST_IsBottommostLevel(
 bool Compaction::IsFullCompaction(
    VersionStorageInfo* vstorage,
    const std::vector<CompactionInputFiles>& inputs) {
-  int num_files_in_compaction = 0;
-  int total_num_files = 0;
+  size_t num_files_in_compaction = 0;
+  size_t total_num_files = 0;
  for (int l = 0; l < vstorage->num_levels(); l++) {
    total_num_files += vstorage->NumLevelFiles(l);
  }
@@ -147,7 +147,8 @@ Compaction::Compaction(VersionStorageInfo* vstorage,
                       uint32_t _output_path_id, CompressionType _compression,
                       std::vector<FileMetaData*> _grandparents,
                       bool _manual_compaction, double _score,
-                       bool _deletion_compaction)
+                       bool _deletion_compaction,
+                       CompactionReason _compaction_reason)
    : start_level_(_inputs[0].level),
      output_level_(_output_level),
      max_output_file_size_(_target_file_size),
@@ -167,8 +168,12 @@ Compaction::Compaction(VersionStorageInfo* vstorage,
      score_(_score),
      bottommost_level_(IsBottommostLevel(output_level_, vstorage, inputs_)),
      is_full_compaction_(IsFullCompaction(vstorage, inputs_)),
-      is_manual_compaction_(_manual_compaction) {
+      is_manual_compaction_(_manual_compaction),
+      compaction_reason_(_compaction_reason) {
  MarkFilesBeingCompacted(true);
+  if (is_manual_compaction_) {
+    compaction_reason_ = CompactionReason::kManualCompaction;
+  }

 #ifndef NDEBUG
  for (size_t i = 1; i < inputs_.size(); ++i) {
@@ -184,6 +189,9 @@ Compaction::Compaction(VersionStorageInfo* vstorage,
                                &arena_);
    }
  }
+
+  Slice smallest_user_key;
+  GetBoundaryKeys(vstorage, inputs_, &smallest_user_key, &largest_user_key_);
 }

 Compaction::~Compaction() {
@@ -311,7 +319,7 @@ bool Compaction::ShouldStopBefore(const Slice& internal_key) {
 // Mark (or clear) each file that is being compacted
 void Compaction::MarkFilesBeingCompacted(bool mark_as_compacted) {
  for (size_t i = 0; i < num_input_levels(); i++) {
-    for (unsigned int j = 0; j < inputs_[i].size(); j++) {
+    for (size_t j = 0; j < inputs_[i].size(); j++) {
      assert(mark_as_compacted ? !inputs_[i][j]->being_compacted :
                                  inputs_[i][j]->being_compacted);
      inputs_[i][j]->being_compacted = mark_as_compacted;
@@ -371,7 +379,7 @@ int InputSummary(const std::vector<FileMetaData*>& files, char* output,
                 int len) {
  *output = '\0';
  int write = 0;
-  for (unsigned int i = 0; i < files.size(); i++) {
+  for (size_t i = 0; i < files.size(); i++) {
    int sz = len - write;
    int ret;
    char sztxt[16];
@@ -428,7 +436,7 @@ uint64_t Compaction::OutputFilePreallocationSize() {
  }
  // Over-estimate slightly so we don't end up just barely crossing
  // the threshold
-  return preallocation_size * 1.1;
+  return preallocation_size + (preallocation_size / 10);
 }

 std::unique_ptr<CompactionFilter> Compaction::CreateCompactionFilter() const {
@@ -439,6 +447,7 @@ std::unique_ptr<CompactionFilter> Compaction::CreateCompactionFilter() const {
  CompactionFilter::Context context;
  context.is_full_compaction = is_full_compaction_;
  context.is_manual_compaction = is_manual_compaction_;
+  context.column_family_id = cfd_->GetID();
  return cfd_->ioptions()->compaction_filter_factory->CreateCompactionFilter(
      context);
 }
@@ -41,7 +41,8 @@ class Compaction {
             uint32_t output_path_id, CompressionType compression,
             std::vector<FileMetaData*> grandparents,
             bool manual_compaction = false, double score = -1,
-             bool deletion_compaction = false);
+             bool deletion_compaction = false,
+             CompactionReason compaction_reason = CompactionReason::kUnknown);

  // No copying allowed
  Compaction(const Compaction&) = delete;
@@ -210,6 +211,18 @@ class Compaction {
      int output_level, VersionStorageInfo* vstorage,
      const std::vector<CompactionInputFiles>& inputs);

+  TablePropertiesCollection GetOutputTableProperties() const {
+    return output_table_properties_;
+  }
+
+  void SetOutputTableProperties(TablePropertiesCollection tp) {
+    output_table_properties_ = std::move(tp);
+  }
+
+  Slice GetLargestUserKey() const { return largest_user_key_; }
+
+  CompactionReason compaction_reason() { return compaction_reason_; }
+
 private:
  // mark (or clear) all files that are being compacted
  void MarkFilesBeingCompacted(bool mark_as_compacted);
@@ -273,6 +286,15 @@ class Compaction {

  // Does input compression match the output compression?
  bool InputCompressionMatchesOutput() const;
+
+  // table properties of output files
+  TablePropertiesCollection output_table_properties_;
+
+  // largest user keys in compaction
+  Slice largest_user_key_;
+
+  // Reason for compaction
+  CompactionReason compaction_reason_;
 };

 // Utility function
@@ -6,18 +6,21 @@
 //  of patent rights can be found in the PATENTS file in the same directory.

 #include "db/compaction_iterator.h"
+#include "table/internal_iterator.h"

 namespace rocksdb {

 CompactionIterator::CompactionIterator(
-    Iterator* input, const Comparator* cmp, MergeHelper* merge_helper,
+    InternalIterator* input, const Comparator* cmp, MergeHelper* merge_helper,
    SequenceNumber last_sequence, std::vector<SequenceNumber>* snapshots,
-    Env* env, bool expect_valid_internal_key, Compaction* compaction,
+    SequenceNumber earliest_write_conflict_snapshot, Env* env,
+    bool expect_valid_internal_key, Compaction* compaction,
    const CompactionFilter* compaction_filter, LogBuffer* log_buffer)
    : input_(input),
      cmp_(cmp),
      merge_helper_(merge_helper),
      snapshots_(snapshots),
+      earliest_write_conflict_snapshot_(earliest_write_conflict_snapshot),
      env_(env),
      expect_valid_internal_key_(expect_valid_internal_key),
      compaction_(compaction),
@@ -41,6 +44,11 @@ CompactionIterator::CompactionIterator(
    earliest_snapshot_ = snapshots_->at(0);
    latest_snapshot_ = snapshots_->back();
  }
+  if (compaction_filter_ != nullptr && compaction_filter_->IgnoreSnapshots()) {
+    ignore_snapshots_ = true;
+  } else {
+    ignore_snapshots_ = false;
+  }
 }

 void CompactionIterator::ResetRecordCounts() {
@@ -89,6 +97,11 @@ void CompactionIterator::Next() {
    NextFromInput();
  }

+  if (valid_) {
+    // Record that we've ouputted a record for the current key.
+    has_outputted_key_ = true;
+  }
+
  PrepareOutput();
 }

@@ -135,11 +148,14 @@ void CompactionIterator::NextFromInput() {
      key_ = current_key_.SetKey(key_, &ikey_);
      current_user_key_ = ikey_.user_key;
      has_current_user_key_ = true;
+      has_outputted_key_ = false;
      current_user_key_sequence_ = kMaxSequenceNumber;
      current_user_key_snapshot_ = 0;
+
      // apply the compaction filter to the first occurrence of the user key
      if (compaction_filter_ != nullptr && ikey_.type == kTypeValue &&
-          (visible_at_tip_ || ikey_.sequence > latest_snapshot_)) {
+          (visible_at_tip_ || ikey_.sequence > latest_snapshot_ ||
+           ignore_snapshots_)) {
        // If the user has specified a compaction filter and the sequence
        // number is greater than any external snapshot, then invoke the
        // filter. If the return value of the compaction filter is true,
@@ -169,6 +185,9 @@ void CompactionIterator::NextFromInput() {
    } else {
      // Update the current key to reflect the new sequence number/type without
      // copying the user key.
+      // TODO(rven): Compaction filter does not process keys in this path
+      // Need to have the compaction filter process multiple versions
+      // if we have versions on both sides of a snapshot
      current_key_.UpdateInternalKey(ikey_.sequence, ikey_.type);
      key_ = current_key_.GetKey();
      ikey_.user_key = current_key_.GetUserKey();
@@ -186,31 +205,99 @@ void CompactionIterator::NextFromInput() {
        visible_at_tip_ ? visible_at_tip_ : findEarliestVisibleSnapshot(
                                                ikey_.sequence, &prev_snapshot);

-    if (ikey_.type == kTypeSingleDeletion) {
+    if (clear_and_output_next_key_) {
+      // In the previous iteration we encountered a single delete that we could
+      // not compact out.  We will keep this Put, but can drop it's data.
+      // (See Optimization 3, below.)
+      assert(ikey_.type == kTypeValue);
+      assert(current_user_key_snapshot_ == last_snapshot);
+
+      value_.clear();
+      valid_ = true;
+      clear_and_output_next_key_ = false;
+    } else if (ikey_.type == kTypeSingleDeletion) {
+      // We can compact out a SingleDelete if:
+      // 1) We encounter the corresponding PUT -OR- we know that this key
+      //    doesn't appear past this output level
+      // =AND=
+      // 2) We've already returned a record in this snapshot -OR-
+      //    there are no earlier earliest_write_conflict_snapshot.
+      //
+      // Rule 1 is needed for SingleDelete correctness.  Rule 2 is needed to
+      // allow Transactions to do write-conflict checking (if we compacted away
+      // all keys, then we wouldn't know that a write happened in this
+      // snapshot).  If there is no earlier snapshot, then we know that there
+      // are no active transactions that need to know about any writes.
+      //
+      // Optimization 3:
+      // If we encounter a SingleDelete followed by a PUT and Rule 2 is NOT
+      // true, then we must output a SingleDelete.  In this case, we will decide
+      // to also output the PUT.  While we are compacting less by outputting the
+      // PUT now, hopefully this will lead to better compaction in the future
+      // when Rule 2 is later true (Ie, We are hoping we can later compact out
+      // both the SingleDelete and the Put, while we couldn't if we only
+      // outputted the SingleDelete now).
+      // In this case, we can save space by removing the PUT's value as it will
+      // never be read.
+      //
+      // Deletes and Merges are not supported on the same key that has a
+      // SingleDelete as it is not possible to correctly do any partial
+      // compaction of such a combination of operations.  The result of mixing
+      // those operations for a given key is documented as being undefined.  So
+      // we can choose how to handle such a combinations of operations.  We will
+      // try to compact out as much as we can in these cases.
+
+      // The easiest way to process a SingleDelete during iteration is to peek
+      // ahead at the next key.
      ParsedInternalKey next_ikey;
      input_->Next();

-      // Check whether the current key is valid, not corrupt and the same
+      // Check whether the next key exists, is not corrupt, and is the same key
      // as the single delete.
      if (input_->Valid() && ParseInternalKey(input_->key(), &next_ikey) &&
          cmp_->Equal(ikey_.user_key, next_ikey.user_key)) {
-        // Mixing single deletes and merges is not supported. Consecutive
-        // single deletes are not valid.
-        if (next_ikey.type != kTypeValue) {
-          assert(false);
-          status_ =
-              Status::InvalidArgument("Put expected after single delete.");
-          break;
-        }
-
-        // Check whether the current key belongs to the same snapshot as the
-        // single delete.
+        // Check whether the next key belongs to the same snapshot as the
+        // SingleDelete.
        if (prev_snapshot == 0 || next_ikey.sequence > prev_snapshot) {
-          // Found the matching value, we can drop the single delete and the
-          // value.
-          ++iter_stats_.num_record_drop_hidden;
-          ++iter_stats_.num_record_drop_obsolete;
-          input_->Next();
+          if (next_ikey.type == kTypeSingleDeletion) {
+            // We encountered two SingleDeletes in a row.  This could be due to
+            // unexpected user input.
+            // Skip the first SingleDelete and let the next iteration decide how
+            // to handle the second SingleDelete
+
+            // First SingleDelete has been skipped since we already called
+            // input_->Next().
+            ++iter_stats_.num_record_drop_obsolete;
+          } else if ((ikey_.sequence <= earliest_write_conflict_snapshot_) ||
+                     has_outputted_key_) {
+            // Found a matching value, we can drop the single delete and the
+            // value.  It is safe to drop both records since we've already
+            // outputted a key in this snapshot, or there is no earlier
+            // snapshot (Rule 2 above).
+
+            // Note: it doesn't matter whether the second key is a Put or if it
+            // is an unexpected Merge or Delete.  We will compact it out
+            // either way.
+            ++iter_stats_.num_record_drop_hidden;
+            ++iter_stats_.num_record_drop_obsolete;
+            // Already called input_->Next() once.  Call it a second time to
+            // skip past the second key.
+            input_->Next();
+          } else {
+            // Found a matching value, but we cannot drop both keys since
+            // there is an earlier snapshot and we need to leave behind a record
+            // to know that a write happened in this snapshot (Rule 2 above).
+            // Clear the value and output the SingleDelete. (The value will be
+            // outputted on the next iteration.)
+            ++iter_stats_.num_record_drop_hidden;
+
+            // Setting valid_ to true will output the current SingleDelete
+            valid_ = true;
+
+            // Set up the Put to be outputted in the next iteration.
+            // (Optimization 3).
+            clear_and_output_next_key_ = true;
+          }
        } else {
          // We hit the next snapshot without hitting a put, so the iterator
          // returns the single delete.
@@ -225,11 +312,14 @@ void CompactionIterator::NextFromInput() {
        // iteration. If the next key is corrupt, we return before the
        // comparison, so the value of has_current_user_key does not matter.
        has_current_user_key_ = false;
-        if (compaction_ != nullptr &&
+        if (compaction_ != nullptr && ikey_.sequence <= earliest_snapshot_ &&
            compaction_->KeyNotExistsBeyondOutputLevel(ikey_.user_key,
                                                       &level_ptrs_)) {
+          // Key doesn't exist outside of this range.
+          // Can compact out this SingleDelete.
          ++iter_stats_.num_record_drop_obsolete;
        } else {
+          // Output SingleDelete
          valid_ = true;
        }
      }
@@ -243,6 +333,10 @@ void CompactionIterator::NextFromInput() {
      // same key, then this kv is not visible in any snapshot.
      // Hidden by an newer entry for same user key
      // TODO: why not > ?
+      //
+      // Note: Dropping this key will not affect TransactionDB write-conflict
+      // checking since there has already been a record returned for this key
+      // in this snapshot.
      assert(last_sequence >= current_user_key_sequence_);
      ++iter_stats_.num_record_drop_hidden;  // (A)
      input_->Next();
@@ -261,6 +355,9 @@ void CompactionIterator::NextFromInput() {
      //     smaller sequence numbers will be dropped in the next
      //     few iterations of this loop (by rule (A) above).
      // Therefore this deletion marker is obsolete and can be dropped.
+      //
+      // Note:  Dropping this Delete will not affect TransactionDB
+      // write-conflict checking since it is earlier than any snapshot.
      ++iter_stats_.num_record_drop_obsolete;
      input_->Next();
    } else if (ikey_.type == kTypeMerge) {
@@ -309,9 +406,14 @@ void CompactionIterator::PrepareOutput() {
  // Zeroing out the sequence number leads to better compression.
  // If this is the bottommost level (no files in lower levels)
  // and the earliest snapshot is larger than this seqno
+  // and the userkey differs from the last userkey in compaction
  // then we can squash the seqno to zero.
+
+  // This is safe for TransactionDB write-conflict checking since transactions
+  // only care about sequence number larger than any active snapshots.
  if (bottommost_level_ && valid_ && ikey_.sequence < earliest_snapshot_ &&
-      ikey_.type != kTypeMerge) {
+      ikey_.type != kTypeMerge &&
+      !cmp_->Equal(compaction_->GetLargestUserKey(), ikey_.user_key)) {
    assert(ikey_.type != kTypeDeletion && ikey_.type != kTypeSingleDeletion);
    ikey_.sequence = 0;
    current_key_.UpdateInternalKey(0, ikey_.type);
@@ -37,9 +37,10 @@ struct CompactionIteratorStats {

 class CompactionIterator {
 public:
-  CompactionIterator(Iterator* input, const Comparator* cmp,
+  CompactionIterator(InternalIterator* input, const Comparator* cmp,
                     MergeHelper* merge_helper, SequenceNumber last_sequence,
-                     std::vector<SequenceNumber>* snapshots, Env* env,
+                     std::vector<SequenceNumber>* snapshots,
+                     SequenceNumber earliest_write_conflict_snapshot, Env* env,
                     bool expect_valid_internal_key,
                     Compaction* compaction = nullptr,
                     const CompactionFilter* compaction_filter = nullptr,
@@ -84,10 +85,11 @@ class CompactionIterator {
  inline SequenceNumber findEarliestVisibleSnapshot(
      SequenceNumber in, SequenceNumber* prev_snapshot);

-  Iterator* input_;
+  InternalIterator* input_;
  const Comparator* cmp_;
  MergeHelper* merge_helper_;
  const std::vector<SequenceNumber>* snapshots_;
+  const SequenceNumber earliest_write_conflict_snapshot_;
  Env* env_;
  bool expect_valid_internal_key_;
  Compaction* compaction_;
@@ -98,6 +100,7 @@ class CompactionIterator {
  SequenceNumber visible_at_tip_;
  SequenceNumber earliest_snapshot_;
  SequenceNumber latest_snapshot_;
+  bool ignore_snapshots_;

  // State
  //
@@ -124,6 +127,14 @@ class CompactionIterator {
  Slice current_user_key_;
  SequenceNumber current_user_key_sequence_;
  SequenceNumber current_user_key_snapshot_;
+
+  // True if the iterator has already returned a record for the current key.
+  bool has_outputted_key_ = false;
+
+  // truncated the value of the next key and output it without applying any
+  // compaction rules.  This is used for outputting a put after a single delete.
+  bool clear_and_output_next_key_ = false;
+
  MergeOutputIterator merge_out_iter_;
  std::string compaction_filter_value_;
  // "level_ptrs" holds indices that remember which file of an associated
@@ -20,9 +20,9 @@ class CompactionIteratorTest : public testing::Test {
                                        nullptr, 0U, false, 0));
    iter_.reset(new test::VectorIterator(ks, vs));
    iter_->SeekToFirst();
-    c_iter_.reset(new CompactionIterator(iter_.get(), cmp_, merge_helper_.get(),
-                                         last_sequence, &snapshots_,
-                                         Env::Default(), false));
+    c_iter_.reset(new CompactionIterator(
+        iter_.get(), cmp_, merge_helper_.get(), last_sequence, &snapshots_,
+        kMaxSequenceNumber, Env::Default(), false));
  }

  const Comparator* cmp_;
@@ -77,6 +77,7 @@ struct CompactionJob::SubcompactionState {
  struct Output {
    FileMetaData meta;
    bool finished;
+    std::shared_ptr<const TableProperties> table_properties;
  };

  // State kept for output being generated
@@ -211,6 +212,7 @@ CompactionJob::CompactionJob(
    std::atomic<bool>* shutting_down, LogBuffer* log_buffer,
    Directory* db_directory, Directory* output_directory, Statistics* stats,
    std::vector<SequenceNumber> existing_snapshots,
+    SequenceNumber earliest_write_conflict_snapshot,
    std::shared_ptr<Cache> table_cache, EventLogger* event_logger,
    bool paranoid_file_checks, bool measure_io_stats, const std::string& dbname,
    CompactionJobStats* compaction_job_stats)
@@ -229,6 +231,7 @@ CompactionJob::CompactionJob(
      output_directory_(output_directory),
      stats_(stats),
      existing_snapshots_(std::move(existing_snapshots)),
+      earliest_write_conflict_snapshot_(earliest_write_conflict_snapshot),
      table_cache_(std::move(table_cache)),
      event_logger_(event_logger),
      paranoid_file_checks_(paranoid_file_checks),
@@ -331,11 +334,6 @@ struct RangeWithSize {
      : range(a, b), size(s) {}
 };

-bool SliceCompare(const Comparator* cmp, const Slice& a, const Slice& b) {
-  // Returns true if a < b
-  return cmp->Compare(ExtractUserKey(a), ExtractUserKey(b)) < 0;
-}
-
 // Generates a histogram representing potential divisions of key ranges from
 // the input. It adds the starting and/or ending keys of certain input files
 // to the working set and then finds the approximate size of data in between
@@ -344,14 +342,13 @@ bool SliceCompare(const Comparator* cmp, const Slice& a, const Slice& b) {
 void CompactionJob::GenSubcompactionBoundaries() {
  auto* c = compact_->compaction;
  auto* cfd = c->column_family_data();
-  std::set<Slice, std::function<bool(const Slice& a, const Slice& b)> > bounds(
-      std::bind(&SliceCompare, cfd->user_comparator(), std::placeholders::_1,
-                std::placeholders::_2));
+  const Comparator* cfd_comparator = cfd->user_comparator();
+  std::vector<Slice> bounds;
  int start_lvl = c->start_level();
  int out_lvl = c->output_level();

  // Add the starting and/or ending key of certain input files as a potential
-  // boundary (because we're inserting into a set, it avoids duplicates)
+  // boundary
  for (size_t lvl_idx = 0; lvl_idx < c->num_input_levels(); lvl_idx++) {
    int lvl = c->level(lvl_idx);
    if (lvl >= start_lvl && lvl <= out_lvl) {
@@ -366,27 +363,37 @@ void CompactionJob::GenSubcompactionBoundaries() {
        // For level 0 add the starting and ending key of each file since the
        // files may have greatly differing key ranges (not range-partitioned)
        for (size_t i = 0; i < num_files; i++) {
-          bounds.emplace(flevel->files[i].smallest_key);
-          bounds.emplace(flevel->files[i].largest_key);
+          bounds.emplace_back(flevel->files[i].smallest_key);
+          bounds.emplace_back(flevel->files[i].largest_key);
        }
      } else {
        // For all other levels add the smallest/largest key in the level to
        // encompass the range covered by that level
-        bounds.emplace(flevel->files[0].smallest_key);
-        bounds.emplace(flevel->files[num_files - 1].largest_key);
+        bounds.emplace_back(flevel->files[0].smallest_key);
+        bounds.emplace_back(flevel->files[num_files - 1].largest_key);
        if (lvl == out_lvl) {
          // For the last level include the starting keys of all files since
          // the last level is the largest and probably has the widest key
          // range. Since it's range partitioned, the ending key of one file
          // and the starting key of the next are very close (or identical).
          for (size_t i = 1; i < num_files; i++) {
-            bounds.emplace(flevel->files[i].smallest_key);
+            bounds.emplace_back(flevel->files[i].smallest_key);
          }
        }
      }
    }
  }

+  std::sort(bounds.begin(), bounds.end(),
+    [cfd_comparator] (const Slice& a, const Slice& b) -> bool {
+      return cfd_comparator->Compare(ExtractUserKey(a), ExtractUserKey(b)) < 0;
+    });
+  // Remove duplicated entries from bounds
+  bounds.erase(std::unique(bounds.begin(), bounds.end(),
+    [cfd_comparator] (const Slice& a, const Slice& b) -> bool {
+      return cfd_comparator->Compare(ExtractUserKey(a), ExtractUserKey(b)) == 0;
+    }), bounds.end());
+
  // Combine consecutive pairs of boundaries into ranges with an approximate
  // size of data covered by keys in that range
  uint64_t sum = 0;
@@ -408,9 +415,12 @@ void CompactionJob::GenSubcompactionBoundaries() {

  // Group the ranges into subcompactions
  const double min_file_fill_percent = 4.0 / 5;
-  uint64_t max_output_files = std::ceil(
-      sum / min_file_fill_percent /
-      cfd->GetCurrentMutableCFOptions()->MaxFileSizeForLevel(out_lvl));
+  uint64_t max_output_files = 
+    static_cast<uint64_t>(
+        std::ceil(
+          sum / min_file_fill_percent /
+          cfd->GetCurrentMutableCFOptions()->MaxFileSizeForLevel(out_lvl))
+          );
  uint64_t subcompactions =
      std::min({static_cast<uint64_t>(ranges.size()),
                static_cast<uint64_t>(db_options_.max_subcompactions),
@@ -423,12 +433,12 @@ void CompactionJob::GenSubcompactionBoundaries() {
    // sizes becomes >= the expected mean size of a subcompaction
    sum = 0;
    for (size_t i = 0; i < ranges.size() - 1; i++) {
+      sum += ranges[i].size;
      if (subcompactions == 1) {
        // If there's only one left to schedule then it goes to the end so no
        // need to put an end boundary
-        break;
+        continue;
      }
-      sum += ranges[i].size;
      if (sum >= mean) {
        boundaries_.emplace_back(ExtractUserKey(ranges[i].range.limit));
        sizes_.emplace_back(sum);
@@ -487,6 +497,16 @@ Status CompactionJob::Run() {
    }
  }

+  TablePropertiesCollection tp;
+  for (const auto& state : compact_->sub_compact_states) {
+    for (const auto& output : state.outputs) {
+      auto fn = TableFileName(db_options_.db_paths, output.meta.fd.GetNumber(),
+                              output.meta.fd.GetPathId());
+      tp[fn] = output.table_properties;
+    }
+  }
+  compact_->compaction->SetOutputTableProperties(std::move(tp));
+
  // Finish up all book-keeping to unify the subcompaction results
  AggregateStatistics();
  UpdateCompactionStats();
@@ -574,7 +594,7 @@ Status CompactionJob::Install(const MutableCFOptions& mutable_cf_options,

 void CompactionJob::ProcessKeyValueCompaction(SubcompactionState* sub_compact) {
  assert(sub_compact != nullptr);
-  std::unique_ptr<Iterator> input(
+  std::unique_ptr<InternalIterator> input(
      versions_->MakeInputIterator(sub_compact->compaction));

  AutoThreadOperationStageUpdater stage_updater(
@@ -590,10 +610,10 @@ void CompactionJob::ProcessKeyValueCompaction(SubcompactionState* sub_compact) {
  if (measure_io_stats_) {
    prev_perf_level = GetPerfLevel();
    SetPerfLevel(PerfLevel::kEnableTime);
-    prev_write_nanos = iostats_context.write_nanos;
-    prev_fsync_nanos = iostats_context.fsync_nanos;
-    prev_range_sync_nanos = iostats_context.range_sync_nanos;
-    prev_prepare_write_nanos = iostats_context.prepare_write_nanos;
+    prev_write_nanos = IOSTATS(write_nanos);
+    prev_fsync_nanos = IOSTATS(fsync_nanos);
+    prev_range_sync_nanos = IOSTATS(range_sync_nanos);
+    prev_prepare_write_nanos = IOSTATS(prepare_write_nanos);
  }

  ColumnFamilyData* cfd = sub_compact->compaction->column_family_data();
@@ -627,8 +647,8 @@ void CompactionJob::ProcessKeyValueCompaction(SubcompactionState* sub_compact) {
  Status status;
  sub_compact->c_iter.reset(new CompactionIterator(
      input.get(), cfd->user_comparator(), &merge, versions_->LastSequence(),
-      &existing_snapshots_, env_, false, sub_compact->compaction,
-      compaction_filter));
+      &existing_snapshots_, earliest_write_conflict_snapshot_, env_, false,
+      sub_compact->compaction, compaction_filter));
  auto c_iter = sub_compact->c_iter.get();
  c_iter->SeekToFirst();
  const auto& c_iter_stats = c_iter->iter_stats();
@@ -717,13 +737,13 @@ void CompactionJob::ProcessKeyValueCompaction(SubcompactionState* sub_compact) {

  if (measure_io_stats_) {
    sub_compact->compaction_job_stats.file_write_nanos +=
-        iostats_context.write_nanos - prev_write_nanos;
+        IOSTATS(write_nanos) - prev_write_nanos;
    sub_compact->compaction_job_stats.file_fsync_nanos +=
-        iostats_context.fsync_nanos - prev_fsync_nanos;
+        IOSTATS(fsync_nanos) - prev_fsync_nanos;
    sub_compact->compaction_job_stats.file_range_sync_nanos +=
-        iostats_context.range_sync_nanos - prev_range_sync_nanos;
+        IOSTATS(range_sync_nanos) - prev_range_sync_nanos;
    sub_compact->compaction_job_stats.file_prepare_write_nanos +=
-        iostats_context.prepare_write_nanos - prev_prepare_write_nanos;
+        IOSTATS(prepare_write_nanos) - prev_prepare_write_nanos;
    if (prev_perf_level != PerfLevel::kEnableTime) {
      SetPerfLevel(prev_perf_level);
    }
@@ -800,7 +820,7 @@ Status CompactionJob::FinishCompactionOutputFile(
  if (s.ok() && current_entries > 0) {
    // Verify that the table is usable
    ColumnFamilyData* cfd = sub_compact->compaction->column_family_data();
-    Iterator* iter = cfd->table_cache()->NewIterator(
+    InternalIterator* iter = cfd->table_cache()->NewIterator(
        ReadOptions(), env_options_, cfd->internal_comparator(), meta->fd,
        nullptr, cfd->internal_stats()->GetFileReadHist(
                     compact_->compaction->output_level()),
@@ -814,7 +834,10 @@ Status CompactionJob::FinishCompactionOutputFile(

    delete iter;
    if (s.ok()) {
-      TableFileCreationInfo info(sub_compact->builder->GetTableProperties());
+      auto tp = sub_compact->builder->GetTableProperties();
+      sub_compact->current_output()->table_properties =
+          std::make_shared<TableProperties>(tp);
+      TableFileCreationInfo info(std::move(tp));
      info.db_name = dbname_;
      info.cf_name = cfd->GetName();
      info.file_path =
@@ -897,7 +920,7 @@ Status CompactionJob::OpenCompactionOutputFile(
  unique_ptr<WritableFile> writable_file;
  std::string fname = TableFileName(db_options_.db_paths, file_number,
                                    sub_compact->compaction->output_path_id());
-  Status s = env_->NewWritableFile(fname, &writable_file, env_options_);
+  Status s = NewWritableFile(env_, fname, &writable_file, env_options_);
  if (!s.ok()) {
    Log(InfoLogLevel::ERROR_LEVEL, db_options_.info_log,
        "[%s] [JOB %d] OpenCompactionOutputFiles for table #%" PRIu64
@@ -927,8 +950,8 @@ Status CompactionJob::OpenCompactionOutputFile(
      cfd->ioptions()->optimize_filters_for_hits && bottommost_level_;
  sub_compact->builder.reset(NewTableBuilder(
      *cfd->ioptions(), cfd->internal_comparator(),
-      cfd->int_tbl_prop_collector_factories(), sub_compact->outfile.get(),
-      sub_compact->compaction->output_compression(),
+      cfd->int_tbl_prop_collector_factories(), cfd->GetID(),
+      sub_compact->outfile.get(), sub_compact->compaction->output_compression(),
      cfd->ioptions()->compression_opts, skip_filters));
  LogFlush(db_options_.info_log);
  return s;
@@ -35,9 +35,9 @@
 #include "rocksdb/env.h"
 #include "rocksdb/memtablerep.h"
 #include "rocksdb/transaction_log.h"
+#include "table/scoped_arena_iterator.h"
 #include "util/autovector.h"
 #include "util/event_logger.h"
-#include "util/scoped_arena_iterator.h"
 #include "util/stop_watch.h"
 #include "util/thread_local.h"

@@ -58,6 +58,7 @@ class CompactionJob {
                Directory* db_directory, Directory* output_directory,
                Statistics* stats,
                std::vector<SequenceNumber> existing_snapshots,
+                SequenceNumber earliest_write_conflict_snapshot,
                std::shared_ptr<Cache> table_cache, EventLogger* event_logger,
                bool paranoid_file_checks, bool measure_io_stats,
                const std::string& dbname,
@@ -134,6 +135,12 @@ class CompactionJob {
  // entirely within s1 and s2, then the earlier version of k1 can be safely
  // deleted because that version is not visible in any snapshot.
  std::vector<SequenceNumber> existing_snapshots_;
+
+  // This is the earliest snapshot that could be used for write-conflict
+  // checking by a transaction.  For any user-key newer than this snapshot, we
+  // should make sure not to remove evidence that a write occurred.
+  SequenceNumber earliest_write_conflict_snapshot_;
+
  std::shared_ptr<Cache> table_cache_;

  EventLogger* event_logger_;
@@ -27,6 +27,7 @@
 #include "db/job_context.h"
 #include "db/version_set.h"
 #include "db/write_batch_internal.h"
+#include "memtable/hash_linklist_rep.h"
 #include "port/stack_trace.h"
 #include "rocksdb/cache.h"
 #include "rocksdb/compaction_filter.h"
@@ -47,14 +48,13 @@
 #include "table/block_based_table_factory.h"
 #include "table/mock_table.h"
 #include "table/plain_table_factory.h"
+#include "table/scoped_arena_iterator.h"
 #include "util/compression.h"
 #include "util/hash.h"
-#include "util/hash_linklist_rep.h"
 #include "util/logging.h"
 #include "util/mock_env.h"
 #include "util/mutexlock.h"
 #include "util/rate_limiter.h"
-#include "util/scoped_arena_iterator.h"
 #include "util/statistics.h"
 #include "util/string_util.h"
 #include "util/sync_point.h"
@@ -64,7 +64,7 @@
 #include "util/xfunc.h"
 #include "utilities/merge_operators.h"

-#if !defined(IOS_CROSS_COMPILE) && (!defined(NDEBUG) || !defined(OS_WIN))
+#if !defined(IOS_CROSS_COMPILE)
 #ifndef ROCKSDB_LITE
 namespace rocksdb {

@@ -551,8 +551,9 @@ uint64_t EstimatedFileSize(
  const size_t kFooterSize = 512;

  uint64_t data_size =
+    static_cast<uint64_t>(
      num_records * (key_size + value_size * compression_ratio +
-                     kPerKeyOverhead);
+                     kPerKeyOverhead));

  return data_size + kFooterSize
         + num_records * bloom_bits_per_key / 8      // filter block
@@ -3,6 +3,8 @@
 //  LICENSE file in the root directory of this source tree. An additional grant
 //  of patent rights can be found in the PATENTS file in the same directory.

+#ifndef ROCKSDB_LITE
+
 #include <algorithm>
 #include <map>
 #include <string>
@@ -160,9 +162,12 @@ class CompactionJobTest : public testing::Test {
        auto key = ToString(i * kMatchingKeys + k);
        auto value = ToString(i * kKeysPerFile + k);
        InternalKey internal_key(key, ++sequence_number, kTypeValue);
+
        // This is how the key will look like once it's written in bottommost
        // file
-        InternalKey bottommost_internal_key(key, 0, kTypeValue);
+        InternalKey bottommost_internal_key(
+            key, (key == "9999") ? sequence_number : 0, kTypeValue);
+
        if (corrupt_id(k)) {
          test::CorruptKeyType(&internal_key);
          test::CorruptKeyType(&bottommost_internal_key);
@@ -196,7 +201,7 @@ class CompactionJobTest : public testing::Test {
    unique_ptr<WritableFileWriter> file_writer(
        new WritableFileWriter(std::move(file), env_options_));
    {
-      log::Writer log(std::move(file_writer));
+      log::Writer log(std::move(file_writer), 0, false);
      std::string record;
      new_db.EncodeTo(&record);
      s = log.AddRecord(record);
@@ -215,9 +220,11 @@ class CompactionJobTest : public testing::Test {
    cfd_ = versions_->GetColumnFamilySet()->GetDefault();
  }

-  void RunCompaction(const std::vector<std::vector<FileMetaData*>>& input_files,
-                     const stl_wrappers::KVMap& expected_results,
-                     const std::vector<SequenceNumber>& snapshots = {}) {
+  void RunCompaction(
+      const std::vector<std::vector<FileMetaData*>>& input_files,
+      const stl_wrappers::KVMap& expected_results,
+      const std::vector<SequenceNumber>& snapshots = {},
+      SequenceNumber earliest_write_conflict_snapshot = kMaxSequenceNumber) {
    auto cfd = versions_->GetColumnFamilySet()->GetDefault();

    size_t num_input_files = 0;
@@ -241,11 +248,11 @@ class CompactionJobTest : public testing::Test {
    LogBuffer log_buffer(InfoLogLevel::INFO_LEVEL, db_options_.info_log.get());
    mutex_.Lock();
    EventLogger event_logger(db_options_.info_log.get());
-    CompactionJob compaction_job(0, &compaction, db_options_, env_options_,
-                                 versions_.get(), &shutting_down_, &log_buffer,
-                                 nullptr, nullptr, nullptr, snapshots,
-                                 table_cache_, &event_logger, false, false,
-                                 dbname_, &compaction_job_stats_);
+    CompactionJob compaction_job(
+        0, &compaction, db_options_, env_options_, versions_.get(),
+        &shutting_down_, &log_buffer, nullptr, nullptr, nullptr, snapshots,
+        earliest_write_conflict_snapshot, table_cache_, &event_logger, false,
+        false, dbname_, &compaction_job_stats_);

    VerifyInitializationOfCompactionJobStats(compaction_job_stats_);

@@ -344,7 +351,7 @@ TEST_F(CompactionJobTest, SimpleOverwrite) {

  auto expected_results =
      mock::MakeMockFile({{KeyStr("a", 0U, kTypeValue), "val2"},
-                          {KeyStr("b", 0U, kTypeValue), "val3"}});
+                          {KeyStr("b", 4U, kTypeValue), "val3"}});

  SetLastSequence(4U);
  auto files = cfd_->current()->storage_info()->LevelFiles(0);
@@ -397,7 +404,7 @@ TEST_F(CompactionJobTest, SimpleMerge) {

  auto expected_results =
      mock::MakeMockFile({{KeyStr("a", 0U, kTypeValue), "3,4,5"},
-                          {KeyStr("b", 0U, kTypeValue), "1,2"}});
+                          {KeyStr("b", 2U, kTypeValue), "1,2"}});

  SetLastSequence(5U);
  auto files = cfd_->current()->storage_info()->LevelFiles(0);
@@ -557,34 +564,144 @@ TEST_F(CompactionJobTest, SimpleSingleDelete) {
 TEST_F(CompactionJobTest, SingleDeleteSnapshots) {
  NewDB();

-  auto file1 = mock::MakeMockFile({{KeyStr("A", 12U, kTypeSingleDeletion), ""},
-                                   {KeyStr("a", 12U, kTypeSingleDeletion), ""},
-                                   {KeyStr("b", 21U, kTypeSingleDeletion), ""},
-                                   {KeyStr("c", 22U, kTypeSingleDeletion), ""},
-                                   {KeyStr("d", 9U, kTypeSingleDeletion), ""}});
+  auto file1 = mock::MakeMockFile({
+      {KeyStr("A", 12U, kTypeSingleDeletion), ""},
+      {KeyStr("a", 12U, kTypeSingleDeletion), ""},
+      {KeyStr("b", 21U, kTypeSingleDeletion), ""},
+      {KeyStr("c", 22U, kTypeSingleDeletion), ""},
+      {KeyStr("d", 9U, kTypeSingleDeletion), ""},
+      {KeyStr("f", 21U, kTypeSingleDeletion), ""},
+      {KeyStr("j", 11U, kTypeSingleDeletion), ""},
+      {KeyStr("j", 9U, kTypeSingleDeletion), ""},
+      {KeyStr("k", 12U, kTypeSingleDeletion), ""},
+      {KeyStr("k", 11U, kTypeSingleDeletion), ""},
+      {KeyStr("l", 3U, kTypeSingleDeletion), ""},
+      {KeyStr("l", 2U, kTypeSingleDeletion), ""},
+  });
  AddMockFile(file1);

-  auto file2 = mock::MakeMockFile({{KeyStr("0", 2U, kTypeSingleDeletion), ""},
-                                   {KeyStr("a", 11U, kTypeValue), "val1"},
-                                   {KeyStr("b", 11U, kTypeValue), "val2"},
-                                   {KeyStr("c", 21U, kTypeValue), "val3"},
-                                   {KeyStr("d", 8U, kTypeValue), "val4"},
-                                   {KeyStr("e", 2U, kTypeSingleDeletion), ""}});
+  auto file2 = mock::MakeMockFile({
+      {KeyStr("0", 2U, kTypeSingleDeletion), ""},
+      {KeyStr("a", 11U, kTypeValue), "val1"},
+      {KeyStr("b", 11U, kTypeValue), "val2"},
+      {KeyStr("c", 21U, kTypeValue), "val3"},
+      {KeyStr("d", 8U, kTypeValue), "val4"},
+      {KeyStr("e", 2U, kTypeSingleDeletion), ""},
+      {KeyStr("f", 1U, kTypeValue), "val1"},
+      {KeyStr("g", 11U, kTypeSingleDeletion), ""},
+      {KeyStr("h", 2U, kTypeSingleDeletion), ""},
+      {KeyStr("m", 12U, kTypeValue), "val1"},
+      {KeyStr("m", 11U, kTypeSingleDeletion), ""},
+      {KeyStr("m", 8U, kTypeValue), "val2"},
+  });
  AddMockFile(file2);

-  auto file3 = mock::MakeMockFile({{KeyStr("A", 1U, kTypeValue), "val"},
-                                   {KeyStr("e", 1U, kTypeValue), "val"}});
+  auto file3 = mock::MakeMockFile({
+      {KeyStr("A", 1U, kTypeValue), "val"},
+      {KeyStr("e", 1U, kTypeValue), "val"},
+  });
  AddMockFile(file3, 2);

-  auto expected_results =
-      mock::MakeMockFile({{KeyStr("A", 12U, kTypeSingleDeletion), ""},
-                          {KeyStr("b", 21U, kTypeSingleDeletion), ""},
-                          {KeyStr("b", 11U, kTypeValue), "val2"},
-                          {KeyStr("e", 2U, kTypeSingleDeletion), ""}});
+  auto expected_results = mock::MakeMockFile({
+      {KeyStr("A", 12U, kTypeSingleDeletion), ""},
+      {KeyStr("a", 12U, kTypeSingleDeletion), ""},
+      {KeyStr("a", 11U, kTypeValue), ""},
+      {KeyStr("b", 21U, kTypeSingleDeletion), ""},
+      {KeyStr("b", 11U, kTypeValue), "val2"},
+      {KeyStr("c", 22U, kTypeSingleDeletion), ""},
+      {KeyStr("c", 21U, kTypeValue), ""},
+      {KeyStr("e", 2U, kTypeSingleDeletion), ""},
+      {KeyStr("f", 21U, kTypeSingleDeletion), ""},
+      {KeyStr("f", 1U, kTypeValue), "val1"},
+      {KeyStr("g", 11U, kTypeSingleDeletion), ""},
+      {KeyStr("j", 11U, kTypeSingleDeletion), ""},
+      {KeyStr("k", 11U, kTypeSingleDeletion), ""},
+      {KeyStr("m", 12U, kTypeValue), "val1"},
+      {KeyStr("m", 11U, kTypeSingleDeletion), ""},
+      {KeyStr("m", 8U, kTypeValue), "val2"},
+  });

  SetLastSequence(22U);
  auto files = cfd_->current()->storage_info()->LevelFiles(0);
-  RunCompaction({files}, expected_results, {10U, 20U});
+  RunCompaction({files}, expected_results, {10U, 20U}, 10U);
+}
+
+TEST_F(CompactionJobTest, EarliestWriteConflictSnapshot) {
+  NewDB();
+
+  // Test multiple snapshots where the earliest snapshot is not a
+  // write-conflic-snapshot.
+
+  auto file1 = mock::MakeMockFile({
+      {KeyStr("A", 24U, kTypeSingleDeletion), ""},
+      {KeyStr("A", 23U, kTypeValue), "val"},
+      {KeyStr("B", 24U, kTypeSingleDeletion), ""},
+      {KeyStr("B", 23U, kTypeValue), "val"},
+      {KeyStr("D", 24U, kTypeSingleDeletion), ""},
+      {KeyStr("G", 32U, kTypeSingleDeletion), ""},
+      {KeyStr("G", 31U, kTypeValue), "val"},
+      {KeyStr("G", 24U, kTypeSingleDeletion), ""},
+      {KeyStr("G", 23U, kTypeValue), "val2"},
+      {KeyStr("H", 31U, kTypeValue), "val"},
+      {KeyStr("H", 24U, kTypeSingleDeletion), ""},
+      {KeyStr("H", 23U, kTypeValue), "val"},
+      {KeyStr("I", 35U, kTypeSingleDeletion), ""},
+      {KeyStr("I", 34U, kTypeValue), "val2"},
+      {KeyStr("I", 33U, kTypeSingleDeletion), ""},
+      {KeyStr("I", 32U, kTypeValue), "val3"},
+      {KeyStr("I", 31U, kTypeSingleDeletion), ""},
+      {KeyStr("J", 34U, kTypeValue), "val"},
+      {KeyStr("J", 33U, kTypeSingleDeletion), ""},
+      {KeyStr("J", 25U, kTypeValue), "val2"},
+      {KeyStr("J", 24U, kTypeSingleDeletion), ""},
+  });
+  AddMockFile(file1);
+
+  auto file2 = mock::MakeMockFile({
+      {KeyStr("A", 14U, kTypeSingleDeletion), ""},
+      {KeyStr("A", 13U, kTypeValue), "val2"},
+      {KeyStr("C", 14U, kTypeSingleDeletion), ""},
+      {KeyStr("C", 13U, kTypeValue), "val"},
+      {KeyStr("E", 12U, kTypeSingleDeletion), ""},
+      {KeyStr("F", 4U, kTypeSingleDeletion), ""},
+      {KeyStr("F", 3U, kTypeValue), "val"},
+      {KeyStr("G", 14U, kTypeSingleDeletion), ""},
+      {KeyStr("G", 13U, kTypeValue), "val3"},
+      {KeyStr("H", 14U, kTypeSingleDeletion), ""},
+      {KeyStr("H", 13U, kTypeValue), "val2"},
+      {KeyStr("I", 13U, kTypeValue), "val4"},
+      {KeyStr("I", 12U, kTypeSingleDeletion), ""},
+      {KeyStr("I", 11U, kTypeValue), "val5"},
+      {KeyStr("J", 15U, kTypeValue), "val3"},
+      {KeyStr("J", 14U, kTypeSingleDeletion), ""},
+  });
+  AddMockFile(file2);
+
+  auto expected_results = mock::MakeMockFile({
+      {KeyStr("A", 24U, kTypeSingleDeletion), ""},
+      {KeyStr("A", 23U, kTypeValue), ""},
+      {KeyStr("B", 24U, kTypeSingleDeletion), ""},
+      {KeyStr("B", 23U, kTypeValue), ""},
+      {KeyStr("D", 24U, kTypeSingleDeletion), ""},
+      {KeyStr("E", 12U, kTypeSingleDeletion), ""},
+      {KeyStr("G", 32U, kTypeSingleDeletion), ""},
+      {KeyStr("G", 31U, kTypeValue), ""},
+      {KeyStr("H", 31U, kTypeValue), "val"},
+      {KeyStr("I", 35U, kTypeSingleDeletion), ""},
+      {KeyStr("I", 34U, kTypeValue), ""},
+      {KeyStr("I", 31U, kTypeSingleDeletion), ""},
+      {KeyStr("I", 13U, kTypeValue), "val4"},
+      {KeyStr("J", 34U, kTypeValue), "val"},
+      {KeyStr("J", 33U, kTypeSingleDeletion), ""},
+      {KeyStr("J", 25U, kTypeValue), "val2"},
+      {KeyStr("J", 24U, kTypeSingleDeletion), ""},
+      {KeyStr("J", 15U, kTypeValue), "val3"},
+      {KeyStr("J", 14U, kTypeSingleDeletion), ""},
+  });
+
+  SetLastSequence(24U);
+  auto files = cfd_->current()->storage_info()->LevelFiles(0);
+  RunCompaction({files}, expected_results, {10U, 20U, 30U}, 20U);
 }

 TEST_F(CompactionJobTest, SingleDeleteZeroSeq) {
@@ -602,7 +719,7 @@ TEST_F(CompactionJobTest, SingleDeleteZeroSeq) {
  AddMockFile(file2);

  auto expected_results = mock::MakeMockFile({
-      {KeyStr("dummy", 0U, kTypeValue), "val2"},
+      {KeyStr("dummy", 5U, kTypeValue), "val2"},
  });

  SetLastSequence(22U);
@@ -614,9 +731,22 @@ TEST_F(CompactionJobTest, MultiSingleDelete) {
  // Tests three scenarios involving multiple single delete/put pairs:
  //
  // A: Put Snapshot SDel Put SDel -> Put Snapshot SDel
-  // B: Put SDel Put SDel -> (Removed)
+  // B: Snapshot Put SDel Put SDel Snapshot -> Snapshot SDel Snapshot
  // C: SDel Put SDel Snapshot Put -> Snapshot Put
-  // D: (Put) SDel Snapshot Put SDel -> (Put) SDel Snapshot
+  // D: (Put) SDel Snapshot Put SDel -> (Put) SDel Snapshot SDel
+  // E: Put SDel Snapshot Put SDel -> Snapshot SDel
+  // F: Put SDel Put Sdel Snapshot -> removed
+  // G: Snapshot SDel Put SDel Put -> Snapshot Put SDel
+  // H: (Put) Put SDel Put Sdel Snapshot -> Removed
+  // I: (Put) Snapshot Put SDel Put SDel -> SDel
+  // J: Put Put SDel Put SDel SDel Snapshot Put Put SDel SDel Put
+  //      -> Snapshot Put
+  // K: SDel SDel Put SDel Put Put Snapshot SDel Put SDel SDel Put SDel
+  //      -> Snapshot Put Snapshot SDel
+  // L: SDel Put Del Put SDel Snapshot Del Put Del SDel Put SDel
+  //      -> Snapshot SDel
+  // M: (Put) SDel Put Del Put SDel Snapshot Put Del SDel Put SDel Del
+  //      -> SDel Snapshot Del
  NewDB();

  auto file1 = mock::MakeMockFile({
@@ -628,6 +758,34 @@ TEST_F(CompactionJobTest, MultiSingleDelete) {
      {KeyStr("C", 14U, kTypeValue), "val3"},
      {KeyStr("D", 12U, kTypeSingleDeletion), ""},
      {KeyStr("D", 11U, kTypeValue), "val4"},
+      {KeyStr("G", 15U, kTypeValue), "val"},
+      {KeyStr("G", 14U, kTypeSingleDeletion), ""},
+      {KeyStr("G", 13U, kTypeValue), "val"},
+      {KeyStr("I", 14U, kTypeSingleDeletion), ""},
+      {KeyStr("I", 13U, kTypeValue), "val"},
+      {KeyStr("J", 15U, kTypeValue), "val"},
+      {KeyStr("J", 14U, kTypeSingleDeletion), ""},
+      {KeyStr("J", 13U, kTypeSingleDeletion), ""},
+      {KeyStr("J", 12U, kTypeValue), "val"},
+      {KeyStr("J", 11U, kTypeValue), "val"},
+      {KeyStr("K", 16U, kTypeSingleDeletion), ""},
+      {KeyStr("K", 15U, kTypeValue), "val1"},
+      {KeyStr("K", 14U, kTypeSingleDeletion), ""},
+      {KeyStr("K", 13U, kTypeSingleDeletion), ""},
+      {KeyStr("K", 12U, kTypeValue), "val2"},
+      {KeyStr("K", 11U, kTypeSingleDeletion), ""},
+      {KeyStr("L", 16U, kTypeSingleDeletion), ""},
+      {KeyStr("L", 15U, kTypeValue), "val"},
+      {KeyStr("L", 14U, kTypeSingleDeletion), ""},
+      {KeyStr("L", 13U, kTypeDeletion), ""},
+      {KeyStr("L", 12U, kTypeValue), "val"},
+      {KeyStr("L", 11U, kTypeDeletion), ""},
+      {KeyStr("M", 16U, kTypeDeletion), ""},
+      {KeyStr("M", 15U, kTypeSingleDeletion), ""},
+      {KeyStr("M", 14U, kTypeValue), "val"},
+      {KeyStr("M", 13U, kTypeSingleDeletion), ""},
+      {KeyStr("M", 12U, kTypeDeletion), ""},
+      {KeyStr("M", 11U, kTypeValue), "val"},
  });
  AddMockFile(file1);

@@ -639,24 +797,87 @@ TEST_F(CompactionJobTest, MultiSingleDelete) {
      {KeyStr("C", 9U, kTypeValue), "val6"},
      {KeyStr("C", 8U, kTypeSingleDeletion), ""},
      {KeyStr("D", 10U, kTypeSingleDeletion), ""},
+      {KeyStr("E", 12U, kTypeSingleDeletion), ""},
+      {KeyStr("E", 11U, kTypeValue), "val"},
+      {KeyStr("E", 5U, kTypeSingleDeletion), ""},
+      {KeyStr("E", 4U, kTypeValue), "val"},
+      {KeyStr("F", 6U, kTypeSingleDeletion), ""},
+      {KeyStr("F", 5U, kTypeValue), "val"},
+      {KeyStr("F", 4U, kTypeSingleDeletion), ""},
+      {KeyStr("F", 3U, kTypeValue), "val"},
+      {KeyStr("G", 12U, kTypeSingleDeletion), ""},
+      {KeyStr("H", 6U, kTypeSingleDeletion), ""},
+      {KeyStr("H", 5U, kTypeValue), "val"},
+      {KeyStr("H", 4U, kTypeSingleDeletion), ""},
+      {KeyStr("H", 3U, kTypeValue), "val"},
+      {KeyStr("I", 12U, kTypeSingleDeletion), ""},
+      {KeyStr("I", 11U, kTypeValue), "val"},
+      {KeyStr("J", 6U, kTypeSingleDeletion), ""},
+      {KeyStr("J", 5U, kTypeSingleDeletion), ""},
+      {KeyStr("J", 4U, kTypeValue), "val"},
+      {KeyStr("J", 3U, kTypeSingleDeletion), ""},
+      {KeyStr("J", 2U, kTypeValue), "val"},
+      {KeyStr("K", 8U, kTypeValue), "val3"},
+      {KeyStr("K", 7U, kTypeValue), "val4"},
+      {KeyStr("K", 6U, kTypeSingleDeletion), ""},
+      {KeyStr("K", 5U, kTypeValue), "val5"},
+      {KeyStr("K", 2U, kTypeSingleDeletion), ""},
+      {KeyStr("K", 1U, kTypeSingleDeletion), ""},
+      {KeyStr("L", 5U, kTypeSingleDeletion), ""},
+      {KeyStr("L", 4U, kTypeValue), "val"},
+      {KeyStr("L", 3U, kTypeDeletion), ""},
+      {KeyStr("L", 2U, kTypeValue), "val"},
+      {KeyStr("L", 1U, kTypeSingleDeletion), ""},
+      {KeyStr("M", 10U, kTypeSingleDeletion), ""},
+      {KeyStr("M", 7U, kTypeValue), "val"},
+      {KeyStr("M", 5U, kTypeDeletion), ""},
+      {KeyStr("M", 4U, kTypeValue), "val"},
+      {KeyStr("M", 3U, kTypeSingleDeletion), ""},
  });
  AddMockFile(file2);

  auto file3 = mock::MakeMockFile({
-      {KeyStr("D", 11U, kTypeValue), "val"},
+      {KeyStr("D", 1U, kTypeValue), "val"},
+      {KeyStr("H", 1U, kTypeValue), "val"},
+      {KeyStr("I", 2U, kTypeValue), "val"},
  });
  AddMockFile(file3, 2);

-  auto expected_results = mock::MakeMockFile({
-      {KeyStr("A", 12U, kTypeSingleDeletion), ""},
-      {KeyStr("A", 10U, kTypeValue), "val"},
-      {KeyStr("C", 14U, kTypeValue), "val3"},
-      {KeyStr("D", 10U, kTypeSingleDeletion), ""},
+  auto file4 = mock::MakeMockFile({
+      {KeyStr("M", 1U, kTypeValue), "val"},
  });
+  AddMockFile(file4, 2);
+
+  auto expected_results =
+      mock::MakeMockFile({{KeyStr("A", 14U, kTypeSingleDeletion), ""},
+                          {KeyStr("A", 13U, kTypeValue), ""},
+                          {KeyStr("A", 12U, kTypeSingleDeletion), ""},
+                          {KeyStr("A", 10U, kTypeValue), "val"},
+                          {KeyStr("B", 14U, kTypeSingleDeletion), ""},
+                          {KeyStr("B", 13U, kTypeValue), ""},
+                          {KeyStr("C", 14U, kTypeValue), "val3"},
+                          {KeyStr("D", 12U, kTypeSingleDeletion), ""},
+                          {KeyStr("D", 11U, kTypeValue), ""},
+                          {KeyStr("D", 10U, kTypeSingleDeletion), ""},
+                          {KeyStr("E", 12U, kTypeSingleDeletion), ""},
+                          {KeyStr("E", 11U, kTypeValue), ""},
+                          {KeyStr("G", 15U, kTypeValue), "val"},
+                          {KeyStr("G", 12U, kTypeSingleDeletion), ""},
+                          {KeyStr("I", 14U, kTypeSingleDeletion), ""},
+                          {KeyStr("I", 13U, kTypeValue), ""},
+                          {KeyStr("J", 15U, kTypeValue), "val"},
+                          {KeyStr("K", 16U, kTypeSingleDeletion), ""},
+                          {KeyStr("K", 15U, kTypeValue), ""},
+                          {KeyStr("K", 11U, kTypeSingleDeletion), ""},
+                          {KeyStr("K", 8U, kTypeValue), "val3"},
+                          {KeyStr("L", 16U, kTypeSingleDeletion), ""},
+                          {KeyStr("L", 15U, kTypeValue), ""},
+                          {KeyStr("M", 16U, kTypeDeletion), ""},
+                          {KeyStr("M", 3U, kTypeSingleDeletion), ""}});

  SetLastSequence(22U);
  auto files = cfd_->current()->storage_info()->LevelFiles(0);
-  RunCompaction({files}, expected_results, {10U});
+  RunCompaction({files}, expected_results, {10U}, 10U);
 }

 // This test documents the behavior where a corrupt key follows a deletion or a
@@ -682,7 +903,7 @@ TEST_F(CompactionJobTest, CorruptionAfterDeletion) {
      mock::MakeMockFile({{test::KeyStr("A", 0U, kTypeValue), "val3"},
                          {test::KeyStr("a", 0U, kTypeValue, true), "val"},
                          {test::KeyStr("b", 0U, kTypeValue, true), "val"},
-                          {test::KeyStr("c", 0U, kTypeValue), "val2"}});
+                          {test::KeyStr("c", 1U, kTypeValue), "val2"}});

  SetLastSequence(6U);
  auto files = cfd_->current()->storage_info()->LevelFiles(0);
@@ -695,3 +916,14 @@ int main(int argc, char** argv) {
  ::testing::InitGoogleTest(&argc, argv);
  return RUN_ALL_TESTS();
 }
+
+#else
+#include <stdio.h>
+
+int main(int argc, char** argv) {
+  fprintf(stderr,
+          "SKIPPED as CompactionJobStats is not supported in ROCKSDB_LITE\n");
+  return 0;
+}
+
+#endif  // ROCKSDB_LITE
@@ -243,7 +243,7 @@ bool CompactionPicker::ExpandWhileOverlapping(const std::string& cf_name,
 // Returns true if any one of specified files are being compacted
 bool CompactionPicker::FilesInCompaction(
    const std::vector<FileMetaData*>& files) {
-  for (unsigned int i = 0; i < files.size(); i++) {
+  for (size_t i = 0; i < files.size(); i++) {
    if (files[i]->being_compacted) {
      return true;
    }
@@ -255,16 +255,30 @@ Compaction* CompactionPicker::FormCompaction(
    const CompactionOptions& compact_options,
    const std::vector<CompactionInputFiles>& input_files, int output_level,
    VersionStorageInfo* vstorage, const MutableCFOptions& mutable_cf_options,
-    uint32_t output_path_id) const {
+    uint32_t output_path_id) {
  uint64_t max_grandparent_overlap_bytes =
      output_level + 1 < vstorage->num_levels() ?
          mutable_cf_options.MaxGrandParentOverlapBytes(output_level + 1) :
          std::numeric_limits<uint64_t>::max();
  assert(input_files.size());
-  return new Compaction(
+
+  // TODO(rven ): we might be able to run concurrent level 0 compaction
+  // if the key ranges of the two compactions do not overlap, but for now
+  // we do not allow it.
+  if ((input_files[0].level == 0) && !level0_compactions_in_progress_.empty()) {
+    return nullptr;
+  }
+  auto c = new Compaction(
      vstorage, mutable_cf_options, input_files, output_level,
      compact_options.output_file_size_limit, max_grandparent_overlap_bytes,
      output_path_id, compact_options.compression, /* grandparents */ {}, true);
+
+  // If it's level 0 compaction, make sure we don't execute any other level 0
+  // compactions in parallel
+  if ((c != nullptr) && (input_files[0].level == 0)) {
+    level0_compactions_in_progress_.insert(c);
+  }
+  return c;
 }

 Status CompactionPicker::GetCompactionInputsFromFileNumbers(
@@ -441,7 +455,7 @@ Compaction* CompactionPicker::CompactRange(
    const std::string& cf_name, const MutableCFOptions& mutable_cf_options,
    VersionStorageInfo* vstorage, int input_level, int output_level,
    uint32_t output_path_id, const InternalKey* begin, const InternalKey* end,
-    InternalKey** compaction_end) {
+    InternalKey** compaction_end, bool* manual_conflict) {
  // CompactionPickerFIFO has its own implementation of compact range
  assert(ioptions_.compaction_style != kCompactionStyleFIFO);

@@ -467,6 +481,12 @@ Compaction* CompactionPicker::CompactRange(
      return nullptr;
    }

+    if ((start_level == 0) && (!level0_compactions_in_progress_.empty())) {
+      *manual_conflict = true;
+      // Only one level 0 compaction allowed
+      return nullptr;
+    }
+
    std::vector<CompactionInputFiles> inputs(vstorage->num_levels() -
                                             start_level);
    for (int level = start_level; level < vstorage->num_levels(); level++) {
@@ -475,13 +495,21 @@ Compaction* CompactionPicker::CompactRange(
      for (FileMetaData* f : vstorage->LevelFiles(level)) {
        files.push_back(f);
      }
+      if (FilesInCompaction(files)) {
+        *manual_conflict = true;
+        return nullptr;
+      }
    }
-    return new Compaction(
+    Compaction* c = new Compaction(
        vstorage, mutable_cf_options, std::move(inputs), output_level,
        mutable_cf_options.MaxFileSizeForLevel(output_level),
        /* max_grandparent_overlap_bytes */ LLONG_MAX, output_path_id,
        GetCompressionType(ioptions_, output_level, 1),
        /* grandparents */ {}, /* is manual */ true);
+    if (start_level == 0) {
+      level0_compactions_in_progress_.insert(c);
+    }
+    return c;
  }

  CompactionInputFiles inputs;
@@ -500,6 +528,13 @@ Compaction* CompactionPicker::CompactRange(
    return nullptr;
  }

+  if ((input_level == 0) && (!level0_compactions_in_progress_.empty())) {
+    // Only one level 0 compaction allowed
+    TEST_SYNC_POINT("CompactionPicker::CompactRange:Conflict");
+    *manual_conflict = true;
+    return nullptr;
+  }
+
  // Avoid compacting too much in one shot in case the range is large.
  // But we cannot do this for level-0 since level-0 files can overlap
  // and we must not pick one file and drop another older file if the
@@ -522,9 +557,10 @@ Compaction* CompactionPicker::CompactRange(
  assert(output_path_id < static_cast<uint32_t>(ioptions_.db_paths.size()));

  if (ExpandWhileOverlapping(cf_name, vstorage, &inputs) == false) {
-    // manual compaction is currently single-threaded, so it should never
+    // manual compaction is now multi-threaded, so it can
    // happen that ExpandWhileOverlapping fails
-    assert(false);
+    // we handle it higher in RunManualCompaction
+    *manual_conflict = true;
    return nullptr;
  }

@@ -543,9 +579,10 @@ Compaction* CompactionPicker::CompactRange(
    int parent_index = -1;
    if (!SetupOtherInputs(cf_name, mutable_cf_options, vstorage, &inputs,
                          &output_level_inputs, &parent_index, -1)) {
-      // manual compaction is currently single-threaded, so it should never
+      // manual compaction is now multi-threaded, so it can
      // happen that SetupOtherInputs fails
-      assert(false);
+      // we handle it higher in RunManualCompaction
+      *manual_conflict = true;
      return nullptr;
    }
  }
@@ -554,6 +591,12 @@ Compaction* CompactionPicker::CompactRange(
  if (!output_level_inputs.empty()) {
    compaction_inputs.push_back(output_level_inputs);
  }
+  for (size_t i = 0; i < compaction_inputs.size(); i++) {
+    if (FilesInCompaction(compaction_inputs[i].files)) {
+      *manual_conflict = true;
+      return nullptr;
+    }
+  }

  std::vector<FileMetaData*> grandparents;
  GetGrandparents(vstorage, inputs, output_level_inputs, &grandparents);
@@ -566,6 +609,9 @@ Compaction* CompactionPicker::CompactRange(
      std::move(grandparents), /* is manual compaction */ true);

  TEST_SYNC_POINT_CALLBACK("CompactionPicker::CompactRange:Return", compaction);
+  if (input_level == 0) {
+    level0_compactions_in_progress_.insert(compaction);
+  }
  return compaction;
 }

@@ -870,22 +916,40 @@ Compaction* LevelCompactionPicker::PickCompaction(
  int base_index = -1;
  CompactionInputFiles inputs;
  double score = 0;
+  CompactionReason compaction_reason = CompactionReason::kUnknown;

  // Find the compactions by size on all levels.
+  bool skipped_l0 = false;
  for (int i = 0; i < NumberLevels() - 1; i++) {
    score = vstorage->CompactionScore(i);
    level = vstorage->CompactionScoreLevel(i);
    assert(i == 0 || score <= vstorage->CompactionScore(i - 1));
    if (score >= 1) {
+      if (skipped_l0 && level == vstorage->base_level()) {
+        // If L0->base_level compaction is pending, don't schedule further
+        // compaction from base level. Otherwise L0->base_level compaction
+        // may starve.
+        continue;
+      }
      output_level = (level == 0) ? vstorage->base_level() : level + 1;
      if (PickCompactionBySize(vstorage, level, output_level, &inputs,
                               &parent_index, &base_index) &&
          ExpandWhileOverlapping(cf_name, vstorage, &inputs)) {
        // found the compaction!
+        if (level == 0) {
+          // L0 score = `num L0 files` / `level0_file_num_compaction_trigger`
+          compaction_reason = CompactionReason::kLevelL0FilesNum;
+        } else {
+          // L1+ score = `Level files size` / `MaxBytesForLevel`
+          compaction_reason = CompactionReason::kLevelMaxLevelSize;
+        }
        break;
      } else {
        // didn't find the compaction, clear the inputs
        inputs.clear();
+        if (level == 0) {
+          skipped_l0 = true;
+        }
      }
    }
  }
@@ -898,6 +962,9 @@ Compaction* LevelCompactionPicker::PickCompaction(
    parent_index = base_index = -1;
    PickFilesMarkedForCompactionExperimental(cf_name, vstorage, &inputs, &level,
                                             &output_level);
+    if (!inputs.empty()) {
+      compaction_reason = CompactionReason::kFilesMarkedForCompaction;
+    }
  }
  if (inputs.empty()) {
    return nullptr;
@@ -948,7 +1015,8 @@ Compaction* LevelCompactionPicker::PickCompaction(
      mutable_cf_options.MaxGrandParentOverlapBytes(level),
      GetPathId(ioptions_, mutable_cf_options, output_level),
      GetCompressionType(ioptions_, output_level, vstorage->base_level()),
-      std::move(grandparents), is_manual, score);
+      std::move(grandparents), is_manual, score,
+      false /* deletion_compaction */, compaction_reason);

  // If it's level 0 compaction, make sure we don't execute any other level 0
  // compactions in parallel
@@ -1019,6 +1087,7 @@ bool LevelCompactionPicker::PickCompactionBySize(VersionStorageInfo* vstorage,
  // could be made better by looking at key-ranges that are
  // being compacted at level 0.
  if (level == 0 && !level0_compactions_in_progress_.empty()) {
+    TEST_SYNC_POINT("LevelCompactionPicker::PickCompactionBySize:0");
    return false;
  }

@@ -1095,18 +1164,19 @@ void UniversalCompactionPicker::SortedRun::Dump(char* out_buf,
 }

 void UniversalCompactionPicker::SortedRun::DumpSizeInfo(
-    char* out_buf, size_t out_buf_size, int sorted_run_count) const {
+    char* out_buf, size_t out_buf_size, size_t sorted_run_count) const {
  if (level == 0) {
    assert(file != nullptr);
    snprintf(out_buf, out_buf_size,
-             "file %" PRIu64
-             "[%d] "
+             "file %" PRIu64 "[%" ROCKSDB_PRIszt
+             "] "
             "with size %" PRIu64 " (compensated size %" PRIu64 ")",
             file->fd.GetNumber(), sorted_run_count, file->fd.GetFileSize(),
             file->compensated_file_size);
  } else {
    snprintf(out_buf, out_buf_size,
-             "level %d[%d] "
+             "level %d[%" ROCKSDB_PRIszt
+             "] "
             "with size %" PRIu64 " (compensated size %" PRIu64 ")",
             level, sorted_run_count, size, compensated_file_size);
  }
@@ -1234,8 +1304,9 @@ Compaction* UniversalCompactionPicker::PickCompaction(
  std::vector<SortedRun> sorted_runs =
      CalculateSortedRuns(*vstorage, ioptions_);

-  if (sorted_runs.size() <
-      (unsigned int)mutable_cf_options.level0_file_num_compaction_trigger) {
+  if (sorted_runs.size() == 0 ||
+      sorted_runs.size() <
+          (unsigned int)mutable_cf_options.level0_file_num_compaction_trigger) {
    LogToBuffer(log_buffer, "[%s] Universal: nothing to do\n", cf_name.c_str());
    return nullptr;
  }
@@ -1387,16 +1458,21 @@ Compaction* UniversalCompactionPicker::PickCompactionUniversalReadAmp(

  const SortedRun* sr = nullptr;
  bool done = false;
-  int start_index = 0;
+  size_t start_index = 0;
  unsigned int candidate_count = 0;

  unsigned int max_files_to_compact = std::min(max_merge_width,
                                       max_number_of_files_to_compact);
  min_merge_width = std::max(min_merge_width, 2U);

+  // Caller checks the size before executing this function. This invariant is
+  // important because otherwise we may have a possible integer underflow when
+  // dealing with unsigned types.
+  assert(sorted_runs.size() > 0);
+
  // Considers a candidate file only if it is smaller than the
  // total size accumulated so far.
-  for (unsigned int loop = 0; loop < sorted_runs.size(); loop++) {
+  for (size_t loop = 0; loop < sorted_runs.size(); loop++) {
    candidate_count = 0;

    // Skip files that are already being compacted
@@ -1428,7 +1504,7 @@ Compaction* UniversalCompactionPicker::PickCompactionUniversalReadAmp(
    }

    // Check if the succeeding files need compaction.
-    for (unsigned int i = loop + 1;
+    for (size_t i = loop + 1;
         candidate_count < max_files_to_compact && i < sorted_runs.size();
         i++) {
      const SortedRun* succeeding_sr = &sorted_runs[i];
@@ -1470,7 +1546,7 @@ Compaction* UniversalCompactionPicker::PickCompactionUniversalReadAmp(
      done = true;
      break;
    } else {
-      for (unsigned int i = loop;
+      for (size_t i = loop;
           i < loop + candidate_count && i < sorted_runs.size(); i++) {
        const SortedRun* skipping_sr = &sorted_runs[i];
        char file_num_buf[256];
@@ -1483,7 +1559,7 @@ Compaction* UniversalCompactionPicker::PickCompactionUniversalReadAmp(
  if (!done || candidate_count <= 1) {
    return nullptr;
  }
-  unsigned int first_index_after = start_index + candidate_count;
+  size_t first_index_after = start_index + candidate_count;
  // Compression is enabled if files compacted earlier already reached
  // size ratio of compression.
  bool enable_compression = true;
@@ -1524,7 +1600,7 @@ Compaction* UniversalCompactionPicker::PickCompactionUniversalReadAmp(
  for (size_t i = 0; i < inputs.size(); ++i) {
    inputs[i].level = start_level + static_cast<int>(i);
  }
-  for (unsigned int i = start_index; i < first_index_after; i++) {
+  for (size_t i = start_index; i < first_index_after; i++) {
    auto& picking_sr = sorted_runs[i];
    if (picking_sr.level == 0) {
      FileMetaData* picking_file = picking_sr.file;
@@ -1541,11 +1617,18 @@ Compaction* UniversalCompactionPicker::PickCompactionUniversalReadAmp(
                file_num_buf);
  }

+  CompactionReason compaction_reason;
+  if (max_number_of_files_to_compact == UINT_MAX) {
+    compaction_reason = CompactionReason::kUniversalSortedRunNum;
+  } else {
+    compaction_reason = CompactionReason::kUniversalSizeRatio;
+  }
  return new Compaction(
      vstorage, mutable_cf_options, std::move(inputs), output_level,
      mutable_cf_options.MaxFileSizeForLevel(output_level), LLONG_MAX, path_id,
      GetCompressionType(ioptions_, start_level, 1, enable_compression),
-      /* grandparents */ {}, /* is manual */ false, score);
+      /* grandparents */ {}, /* is manual */ false, score,
+      false /* deletion_compaction */, compaction_reason);
 }

 // Look at overall size amplification. If size amplification
@@ -1564,11 +1647,11 @@ Compaction* UniversalCompactionPicker::PickCompactionUniversalSizeAmp(

  unsigned int candidate_count = 0;
  uint64_t candidate_size = 0;
-  unsigned int start_index = 0;
+  size_t start_index = 0;
  const SortedRun* sr = nullptr;

  // Skip files that are already being compacted
-  for (unsigned int loop = 0; loop < sorted_runs.size() - 1; loop++) {
+  for (size_t loop = 0; loop < sorted_runs.size() - 1; loop++) {
    sr = &sorted_runs[loop];
    if (!sr->being_compacted) {
      start_index = loop;         // Consider this as the first candidate.
@@ -1588,13 +1671,14 @@ Compaction* UniversalCompactionPicker::PickCompactionUniversalSizeAmp(
  {
    char file_num_buf[kFormatFileNumberBufSize];
    sr->Dump(file_num_buf, sizeof(file_num_buf), true);
-    LogToBuffer(log_buffer, "[%s] Universal: First candidate %s[%d] %s",
+    LogToBuffer(log_buffer,
+                "[%s] Universal: First candidate %s[%" ROCKSDB_PRIszt "] %s",
                cf_name.c_str(), file_num_buf, start_index,
                " to reduce size amp.\n");
  }

  // keep adding up all the remaining files
-  for (unsigned int loop = start_index; loop < sorted_runs.size() - 1; loop++) {
+  for (size_t loop = start_index; loop < sorted_runs.size() - 1; loop++) {
    sr = &sorted_runs[loop];
    if (sr->being_compacted) {
      char file_num_buf[kFormatFileNumberBufSize];
@@ -1634,7 +1718,7 @@ Compaction* UniversalCompactionPicker::PickCompactionUniversalSizeAmp(

  // Estimate total file size
  uint64_t estimated_total_size = 0;
-  for (unsigned int loop = start_index; loop < sorted_runs.size(); loop++) {
+  for (size_t loop = start_index; loop < sorted_runs.size(); loop++) {
    estimated_total_size += sorted_runs[loop].size;
  }
  uint32_t path_id = GetPathId(ioptions_, estimated_total_size);
@@ -1645,7 +1729,7 @@ Compaction* UniversalCompactionPicker::PickCompactionUniversalSizeAmp(
    inputs[i].level = start_level + static_cast<int>(i);
  }
  // We always compact all the files, so always compress.
-  for (unsigned int loop = start_index; loop < sorted_runs.size(); loop++) {
+  for (size_t loop = start_index; loop < sorted_runs.size(); loop++) {
    auto& picking_sr = sorted_runs[loop];
    if (picking_sr.level == 0) {
      FileMetaData* f = picking_sr.file;
@@ -1657,7 +1741,7 @@ Compaction* UniversalCompactionPicker::PickCompactionUniversalSizeAmp(
      }
    }
    char file_num_buf[256];
-    sr->DumpSizeInfo(file_num_buf, sizeof(file_num_buf), loop);
+    picking_sr.DumpSizeInfo(file_num_buf, sizeof(file_num_buf), loop);
    LogToBuffer(log_buffer, "[%s] Universal: size amp picking %s",
                cf_name.c_str(), file_num_buf);
  }
@@ -1668,7 +1752,9 @@ Compaction* UniversalCompactionPicker::PickCompactionUniversalSizeAmp(
      mutable_cf_options.MaxFileSizeForLevel(vstorage->num_levels() - 1),
      /* max_grandparent_overlap_bytes */ LLONG_MAX, path_id,
      GetCompressionType(ioptions_, vstorage->num_levels() - 1, 1),
-      /* grandparents */ {}, /* is manual */ false, score);
+      /* grandparents */ {}, /* is manual */ false, score,
+      false /* deletion_compaction */,
+      CompactionReason::kUniversalSizeAmplification);
 }

 bool FIFOCompactionPicker::NeedsCompaction(const VersionStorageInfo* vstorage)
@@ -1727,7 +1813,7 @@ Compaction* FIFOCompactionPicker::PickCompaction(
  Compaction* c = new Compaction(
      vstorage, mutable_cf_options, std::move(inputs), 0, 0, 0, 0,
      kNoCompression, {}, /* is manual */ false, vstorage->CompactionScore(0),
-      /* is deletion compaction */ true);
+      /* is deletion compaction */ true, CompactionReason::kFIFOMaxSize);
  level0_compactions_in_progress_.insert(c);
  return c;
 }
@@ -1736,7 +1822,7 @@ Compaction* FIFOCompactionPicker::CompactRange(
    const std::string& cf_name, const MutableCFOptions& mutable_cf_options,
    VersionStorageInfo* vstorage, int input_level, int output_level,
    uint32_t output_path_id, const InternalKey* begin, const InternalKey* end,
-    InternalKey** compaction_end) {
+    InternalKey** compaction_end, bool* manual_conflict) {
  assert(input_level == 0);
  assert(output_level == 0);
  *compaction_end = nullptr;
@@ -60,7 +60,7 @@ class CompactionPicker {
      const std::string& cf_name, const MutableCFOptions& mutable_cf_options,
      VersionStorageInfo* vstorage, int input_level, int output_level,
      uint32_t output_path_id, const InternalKey* begin, const InternalKey* end,
-      InternalKey** compaction_end);
+      InternalKey** compaction_end, bool* manual_conflict);

  // The maximum allowed output level.  Default value is NumberLevels() - 1.
  virtual int MaxOutputLevel() const {
@@ -94,7 +94,7 @@ class CompactionPicker {
      const CompactionOptions& compact_options,
      const std::vector<CompactionInputFiles>& input_files, int output_level,
      VersionStorageInfo* vstorage, const MutableCFOptions& mutable_cf_options,
-      uint32_t output_path_id) const;
+      uint32_t output_path_id);

  // Converts a set of compaction input file numbers into
  // a list of CompactionInputFiles.
@@ -251,7 +251,7 @@ class UniversalCompactionPicker : public CompactionPicker {

    // sorted_run_count is added into the string to print
    void DumpSizeInfo(char* out_buf, size_t out_buf_size,
-                      int sorted_run_count) const;
+                      size_t sorted_run_count) const;

    int level;
    // `file` Will be null for level > 0. For level = 0, the sorted run is
@@ -302,7 +302,7 @@ class FIFOCompactionPicker : public CompactionPicker {
      const std::string& cf_name, const MutableCFOptions& mutable_cf_options,
      VersionStorageInfo* vstorage, int input_level, int output_level,
      uint32_t output_path_id, const InternalKey* begin, const InternalKey* end,
-      InternalKey** compaction_end) override;
+      InternalKey** compaction_end, bool* manual_conflict) override;

  // The maximum allowed output level.  Always returns 0.
  virtual int MaxOutputLevel() const override {
@@ -329,11 +329,13 @@ class NullCompactionPicker : public CompactionPicker {
  }

  // Always return "nullptr"
-  Compaction* CompactRange(
-      const std::string& cf_name, const MutableCFOptions& mutable_cf_options,
-      VersionStorageInfo* vstorage, int input_level, int output_level,
-      uint32_t output_path_id, const InternalKey* begin, const InternalKey* end,
-      InternalKey** compaction_end) override {
+  Compaction* CompactRange(const std::string& cf_name,
+                           const MutableCFOptions& mutable_cf_options,
+                           VersionStorageInfo* vstorage, int input_level,
+                           int output_level, uint32_t output_path_id,
+                           const InternalKey* begin, const InternalKey* end,
+                           InternalKey** compaction_end,
+                           bool* manual_conflict) override {
    return nullptr;
  }

@@ -580,6 +580,101 @@ TEST_F(CompactionPickerTest, OverlappingUserKeys3) {
  ASSERT_EQ(7U, compaction->input(1, 1)->fd.GetNumber());
 }

+TEST_F(CompactionPickerTest, NotScheduleL1IfL0WithHigherPri1) {
+  NewVersionStorage(6, kCompactionStyleLevel);
+  mutable_cf_options_.level0_file_num_compaction_trigger = 2;
+  mutable_cf_options_.max_bytes_for_level_base = 900000000U;
+
+  // 6 L0 files, score 3.
+  Add(0, 1U, "000", "400", 1U);
+  Add(0, 2U, "001", "400", 1U, 0, 0);
+  Add(0, 3U, "001", "400", 1000000000U, 0, 0);
+  Add(0, 31U, "001", "400", 1000000000U, 0, 0);
+  Add(0, 32U, "001", "400", 1000000000U, 0, 0);
+  Add(0, 33U, "001", "400", 1000000000U, 0, 0);
+
+  // L1 total size 2GB, score 2.2. If one file being comapcted, score 1.1.
+  Add(1, 4U, "050", "300", 1000000000U, 0, 0);
+  file_map_[4u].first->being_compacted = true;
+  Add(1, 5U, "301", "350", 1000000000U, 0, 0);
+
+  // Output level overlaps with the beginning and the end of the chain
+  Add(2, 6U, "050", "100", 1U);
+  Add(2, 7U, "300", "400", 1U);
+
+  // No compaction should be scheduled, if L0 has higher priority than L1
+  // but L0->L1 compaction is blocked by a file in L1 being compacted.
+  UpdateVersionStorageInfo();
+  ASSERT_EQ(0, vstorage_->CompactionScoreLevel(0));
+  ASSERT_EQ(1, vstorage_->CompactionScoreLevel(1));
+  std::unique_ptr<Compaction> compaction(level_compaction_picker.PickCompaction(
+      cf_name_, mutable_cf_options_, vstorage_.get(), &log_buffer_));
+  ASSERT_TRUE(compaction.get() == nullptr);
+}
+
+TEST_F(CompactionPickerTest, NotScheduleL1IfL0WithHigherPri2) {
+  NewVersionStorage(6, kCompactionStyleLevel);
+  mutable_cf_options_.level0_file_num_compaction_trigger = 2;
+  mutable_cf_options_.max_bytes_for_level_base = 900000000U;
+
+  // 6 L0 files, score 3.
+  Add(0, 1U, "000", "400", 1U);
+  Add(0, 2U, "001", "400", 1U, 0, 0);
+  Add(0, 3U, "001", "400", 1000000000U, 0, 0);
+  Add(0, 31U, "001", "400", 1000000000U, 0, 0);
+  Add(0, 32U, "001", "400", 1000000000U, 0, 0);
+  Add(0, 33U, "001", "400", 1000000000U, 0, 0);
+
+  // L1 total size 2GB, score 2.2. If one file being comapcted, score 1.1.
+  Add(1, 4U, "050", "300", 1000000000U, 0, 0);
+  Add(1, 5U, "301", "350", 1000000000U, 0, 0);
+
+  // Output level overlaps with the beginning and the end of the chain
+  Add(2, 6U, "050", "100", 1U);
+  Add(2, 7U, "300", "400", 1U);
+
+  // If no file in L1 being compacted, L0->L1 compaction will be scheduled.
+  UpdateVersionStorageInfo();  // being_compacted flag is cleared here.
+  ASSERT_EQ(0, vstorage_->CompactionScoreLevel(0));
+  ASSERT_EQ(1, vstorage_->CompactionScoreLevel(1));
+  std::unique_ptr<Compaction> compaction(level_compaction_picker.PickCompaction(
+      cf_name_, mutable_cf_options_, vstorage_.get(), &log_buffer_));
+  ASSERT_TRUE(compaction.get() != nullptr);
+}
+
+TEST_F(CompactionPickerTest, NotScheduleL1IfL0WithHigherPri3) {
+  NewVersionStorage(6, kCompactionStyleLevel);
+  mutable_cf_options_.level0_file_num_compaction_trigger = 2;
+  mutable_cf_options_.max_bytes_for_level_base = 900000000U;
+
+  // 6 L0 files, score 3.
+  Add(0, 1U, "000", "400", 1U);
+  Add(0, 2U, "001", "400", 1U, 0, 0);
+  Add(0, 3U, "001", "400", 1000000000U, 0, 0);
+  Add(0, 31U, "001", "400", 1000000000U, 0, 0);
+  Add(0, 32U, "001", "400", 1000000000U, 0, 0);
+  Add(0, 33U, "001", "400", 1000000000U, 0, 0);
+
+  // L1 score more than 6.
+  Add(1, 4U, "050", "300", 1000000000U, 0, 0);
+  file_map_[4u].first->being_compacted = true;
+  Add(1, 5U, "301", "350", 1000000000U, 0, 0);
+  Add(1, 51U, "351", "400", 6000000000U, 0, 0);
+
+  // Output level overlaps with the beginning and the end of the chain
+  Add(2, 6U, "050", "100", 1U);
+  Add(2, 7U, "300", "400", 1U);
+
+  // If score in L1 is larger than L0, L1 compaction goes through despite
+  // there is pending L0 compaction.
+  UpdateVersionStorageInfo();
+  ASSERT_EQ(1, vstorage_->CompactionScoreLevel(0));
+  ASSERT_EQ(0, vstorage_->CompactionScoreLevel(1));
+  std::unique_ptr<Compaction> compaction(level_compaction_picker.PickCompaction(
+      cf_name_, mutable_cf_options_, vstorage_.get(), &log_buffer_));
+  ASSERT_TRUE(compaction.get() != nullptr);
+}
+
 TEST_F(CompactionPickerTest, EstimateCompactionBytesNeeded1) {
  int num_levels = ioptions_.num_levels;
  ioptions_.level_compaction_dynamic_level_bytes = false;
@@ -7,10 +7,11 @@
 #include <map>
 #include <string>

+#include "memtable/stl_wrappers.h"
 #include "rocksdb/db.h"
 #include "rocksdb/env.h"
 #include "util/hash.h"
-#include "util/stl_wrappers.h"
+#include "util/kv_map.h"
 #include "util/string_util.h"
 #include "util/testharness.h"
 #include "util/testutil.h"
@@ -18,6 +18,13 @@ namespace rocksdb {
 void CancelAllBackgroundWork(DB* db, bool wait) {
  (dynamic_cast<DBImpl*>(db))->CancelAllBackgroundWork(wait);
 }
+
+Status DeleteFilesInRange(DB* db, ColumnFamilyHandle* column_family,
+                          const Slice* begin, const Slice* end) {
+  return (dynamic_cast<DBImpl*>(db))
+      ->DeleteFilesInRange(column_family, begin, end);
+}
+
 }  // namespace rocksdb

 #endif  // ROCKSDB_LITE
@@ -11,6 +11,7 @@

 #include "rocksdb/db.h"

+#include <inttypes.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <sys/stat.h>
@@ -104,8 +105,8 @@ class CorruptionTest : public testing::Test {
  }

  void Check(int min_expected, int max_expected) {
-    unsigned int next_expected = 0;
-    int missed = 0;
+    uint64_t next_expected = 0;
+    uint64_t missed = 0;
    int bad_keys = 0;
    int bad_values = 0;
    int correct = 0;
@@ -126,7 +127,7 @@ class CorruptionTest : public testing::Test {
        continue;
      }
      missed += (key - next_expected);
-      next_expected = static_cast<unsigned int>(key + 1);
+      next_expected = key + 1;
      if (iter->value() != Value(static_cast<int>(key), &value_space)) {
        bad_values++;
      } else {
@@ -136,8 +137,9 @@ class CorruptionTest : public testing::Test {
    delete iter;

    fprintf(stderr,
-            "expected=%d..%d; got=%d; bad_keys=%d; bad_values=%d; missed=%d\n",
-            min_expected, max_expected, correct, bad_keys, bad_values, missed);
+      "expected=%d..%d; got=%d; bad_keys=%d; bad_values=%d; missed=%llu\n",
+            min_expected, max_expected, correct, bad_keys, bad_values,
+            static_cast<unsigned long long>(missed));
    ASSERT_LE(min_expected, correct);
    ASSERT_GE(max_expected, correct);
  }
@@ -183,7 +185,7 @@ class CorruptionTest : public testing::Test {
    FileType type;
    std::string fname;
    int picked_number = -1;
-    for (unsigned int i = 0; i < filenames.size(); i++) {
+    for (size_t i = 0; i < filenames.size(); i++) {
      if (ParseFileName(filenames[i], &number, &type) &&
          type == filetype &&
          static_cast<int>(number) > picked_number) {  // Pick latest file
@@ -232,8 +234,16 @@ class CorruptionTest : public testing::Test {

  // Return the value to associate with the specified key
  Slice Value(int k, std::string* storage) {
-    Random r(k);
-    return test::RandomString(&r, kValueSize, storage);
+    if (k == 0) {
+      // Ugh.  Random seed of 0 used to produce no entropy.  This code
+      // preserves the implementation that was in place when all of the
+      // magic values in this file were picked.
+      *storage = std::string(kValueSize, ' ');
+      return Slice(*storage);
+    } else {
+      Random r(k);
+      return test::RandomString(&r, kValueSize, storage);
+    }
  }
 };

@@ -39,6 +39,7 @@ int main() {
 #include <condition_variable>
 #include <mutex>
 #include <thread>
+#include <unordered_map>

 #include "db/db_impl.h"
 #include "db/version_set.h"
@@ -315,7 +316,7 @@ DEFINE_int32(compaction_style, (int32_t) rocksdb::Options().compaction_style,
             "style of compaction: level-based vs universal");

 static rocksdb::CompactionPri FLAGS_compaction_pri_e;
-DEFINE_int32(compaction_pri, (int32_t)rocksdb::Options().compaction_style,
+DEFINE_int32(compaction_pri, (int32_t)rocksdb::Options().compaction_pri,
             "priority of files to compaction: by size or by data age");

 DEFINE_int32(universal_size_ratio, 0,
@@ -373,6 +374,15 @@ DEFINE_int32(new_table_reader_for_compaction_inputs, true,

 DEFINE_int32(compaction_readahead_size, 0, "Compaction readahead size");

+DEFINE_int32(random_access_max_buffer_size, 1024 * 1024,
+             "Maximum windows randomaccess buffer size");
+
+DEFINE_int32(writable_file_max_buffer_size, 1024 * 1024,
+             "Maximum write buffer for Writable File");
+
+DEFINE_int32(skip_table_builder_flush, false, "Skip flushing block in "
+             "table builder ");
+
 DEFINE_int32(bloom_bits, -1, "Bloom filter bits per key. Negative means"
             " use default settings.");
 DEFINE_int32(memtable_bloom_bits, 0, "Bloom filter bits per key for memtable. "
@@ -410,10 +420,6 @@ static class std::shared_ptr<rocksdb::Statistics> dbstats;
 DEFINE_int64(writes, -1, "Number of write operations to do. If negative, do"
             " --num reads.");

-DEFINE_int32(writes_per_second, 0, "Per-thread rate limit on writes and merges "
-             "  per second. No limit when <= 0. Only for the readwhilewriting "
-             "  and readwhilemerging tests.");
-
 DEFINE_bool(sync, false, "Sync all writes to disk");

 DEFINE_bool(disable_data_sync, false, "If true, do not wait until data is"
@@ -486,6 +492,7 @@ DEFINE_int32(deletepercent, 2, "Percentage of deletes out of reads/writes/"
 DEFINE_uint64(delete_obsolete_files_period_micros, 0,
              "Ignored. Left here for backward compatibility");

+#ifndef ROCKSDB_LITE
 DEFINE_bool(optimistic_transaction_db, false,
            "Open a OptimisticTransactionDB instance. "
            "Required for randomtransaction benchmark.");
@@ -509,6 +516,7 @@ DEFINE_int32(transaction_sleep, 0,
 DEFINE_uint64(transaction_lock_timeout, 100,
              "If using a transaction_db, specifies the lock wait timeout in"
              " milliseconds before failing a transaction waiting on a lock");
+#endif  // ROCKSDB_LITE

 DEFINE_bool(compaction_measure_io_stats, false,
            "Measure times spents on I/Os while in compactions. ");
@@ -620,17 +628,34 @@ static bool ValidateRateLimit(const char* flagname, double value) {
  }
  return true;
 }
-DEFINE_double(soft_rate_limit, 0.0, "");
+DEFINE_double(soft_rate_limit, 0.0, "DEPRECATED");

 DEFINE_double(hard_rate_limit, 0.0, "DEPRECATED");

-DEFINE_uint64(hard_pending_compaction_bytes_limit, 128u * 1024 * 1024 * 1024,
+DEFINE_uint64(soft_pending_compaction_bytes_limit, 64ull * 1024 * 1024 * 1024,
+              "Slowdown writes if pending compaction bytes exceed this number");
+
+DEFINE_uint64(hard_pending_compaction_bytes_limit, 128ull * 1024 * 1024 * 1024,
              "Stop writes if pending compaction bytes exceed this number");

-DEFINE_uint64(delayed_write_rate, 2097152u,
+DEFINE_uint64(delayed_write_rate, 8388608u,
              "Limited bytes allowed to DB when soft_rate_limit or "
              "level0_slowdown_writes_trigger triggers");

+DEFINE_bool(allow_concurrent_memtable_write, false,
+            "Allow multi-writers to update mem tables in parallel.");
+
+DEFINE_bool(enable_write_thread_adaptive_yield, false,
+            "Use a yielding spin loop for brief writer thread waits.");
+
+DEFINE_uint64(
+    write_thread_max_yield_usec, 100,
+    "Maximum microseconds for enable_write_thread_adaptive_yield operation.");
+
+DEFINE_uint64(write_thread_slow_yield_usec, 3,
+              "The threshold at which a slow yield is considered a signal that "
+              "other processes or threads want the core.");
+
 DEFINE_int32(rate_limit_delay_max_milliseconds, 1000,
             "When hard_rate_limit is set then this is the max time a put will"
             " be stalled.");
@@ -639,13 +664,16 @@ DEFINE_uint64(rate_limiter_bytes_per_sec, 0, "Set options.rate_limiter value.");

 DEFINE_uint64(
    benchmark_write_rate_limit, 0,
-    "If non-zero, db_bench will rate-limit the writes going into RocksDB");
+    "If non-zero, db_bench will rate-limit the writes going into RocksDB. This "
+    "is the global rate in bytes/second.");

 DEFINE_int32(max_grandparent_overlap_factor, 10, "Control maximum bytes of "
             "overlaps in grandparent (i.e., level+2) before we stop building a"
             " single file in a level->level+1 compaction.");

+#ifndef ROCKSDB_LITE
 DEFINE_bool(readonly, false, "Run read only benchmarks.");
+#endif  // ROCKSDB_LITE

 DEFINE_bool(disable_auto_compactions, false, "Do not auto trigger compactions");

@@ -728,11 +756,6 @@ DEFINE_bool(identity_as_first_hash, false, "the first hash function of cuckoo "
            "table becomes an identity function. This is only valid when key "
            "is 8 bytes");

-enum PutOrMerge {
-  kPut,
-  kMerge
-};
-
 enum RepFactory {
  kSkipList,
  kPrefixHash,
@@ -983,7 +1006,9 @@ static void AppendWithSpace(std::string* str, Slice msg) {
 struct DBWithColumnFamilies {
  std::vector<ColumnFamilyHandle*> cfh;
  DB* db;
+#ifndef ROCKSDB_LITE
  OptimisticTransactionDB* opt_txn_db;
+#endif  // ROCKSDB_LITE
  std::atomic<size_t> num_created;  // Need to be updated after all the
                                    // new entries in cfh are set.
  size_t num_hot;  // Number of column families to be queried at each moment.
@@ -991,7 +1016,12 @@ struct DBWithColumnFamilies {
                   // Column families will be created and used to be queried.
  port::Mutex create_cf_mutex;  // Only one thread can execute CreateNewCf()

-  DBWithColumnFamilies() : db(nullptr), opt_txn_db(nullptr) {
+  DBWithColumnFamilies()
+      : db(nullptr)
+#ifndef ROCKSDB_LITE
+        , opt_txn_db(nullptr)
+#endif  // ROCKSDB_LITE
+  {
    cfh.clear();
    num_created = 0;
    num_hot = 0;
@@ -1000,7 +1030,9 @@ struct DBWithColumnFamilies {
  DBWithColumnFamilies(const DBWithColumnFamilies& other)
      : cfh(other.cfh),
        db(other.db),
+#ifndef ROCKSDB_LITE
        opt_txn_db(other.opt_txn_db),
+#endif  // ROCKSDB_LITE
        num_created(other.num_created.load()),
        num_hot(other.num_hot) {}

@@ -1008,13 +1040,18 @@ struct DBWithColumnFamilies {
    std::for_each(cfh.begin(), cfh.end(),
                  [](ColumnFamilyHandle* cfhi) { delete cfhi; });
    cfh.clear();
+#ifndef ROCKSDB_LITE
    if (opt_txn_db) {
      delete opt_txn_db;
      opt_txn_db = nullptr;
    } else {
      delete db;
+      db = nullptr;
    }
+#else
+    delete db;
    db = nullptr;
+#endif  // ROCKSDB_LITE
  }

  ColumnFamilyHandle* GetCfh(int64_t rand_num) {
@@ -1136,19 +1173,49 @@ class ReporterAgent {
  bool stop_;
 };

+enum OperationType : unsigned char {
+  kRead = 0,
+  kWrite,
+  kDelete,
+  kSeek,
+  kMerge,
+  kUpdate,
+  kCompress,
+  kUncompress,
+  kCrc,
+  kHash,
+  kOthers
+};
+
+static std::unordered_map<OperationType, std::string, std::hash<unsigned char>>
+                          OperationTypeString = {
+  {kRead, "read"},
+  {kWrite, "write"},
+  {kDelete, "delete"},
+  {kSeek, "seek"},
+  {kMerge, "merge"},
+  {kUpdate, "update"},
+  {kCompress, "compress"},
+  {kCompress, "uncompress"},
+  {kCrc, "crc"},
+  {kHash, "hash"},
+  {kOthers, "op"}
+};
+
 class Stats {
 private:
  int id_;
-  double start_;
-  double finish_;
+  uint64_t start_;
+  uint64_t finish_;
  double seconds_;
-  int64_t done_;
-  int64_t last_report_done_;
-  int64_t next_report_;
-  int64_t bytes_;
-  double last_op_finish_;
-  double last_report_finish_;
-  HistogramImpl hist_;
+  uint64_t done_;
+  uint64_t last_report_done_;
+  uint64_t next_report_;
+  uint64_t bytes_;
+  uint64_t last_op_finish_;
+  uint64_t last_report_finish_;
+  std::unordered_map<OperationType, HistogramImpl,
+                     std::hash<unsigned char>> hist_;
  std::string message_;
  bool exclude_from_merge_;
  ReporterAgent* reporter_agent_;  // does not own
@@ -1164,7 +1231,7 @@ class Stats {
    id_ = id;
    next_report_ = FLAGS_stats_interval ? FLAGS_stats_interval : 100;
    last_op_finish_ = start_;
-    hist_.Clear();
+    hist_.clear();
    done_ = 0;
    last_report_done_ = 0;
    bytes_ = 0;
@@ -1181,7 +1248,15 @@ class Stats {
    if (other.exclude_from_merge_)
      return;

-    hist_.Merge(other.hist_);
+    for (auto it = other.hist_.begin(); it != other.hist_.end(); ++it) {
+      auto this_it = hist_.find(it->first);
+      if (this_it != hist_.end()) {
+        this_it->second.Merge(other.hist_.at(it->first));
+      } else {
+        hist_.insert({ it->first, it->second });
+      }
+    }
+
    done_ += other.done_;
    bytes_ += other.bytes_;
    seconds_ += other.seconds_;
@@ -1234,16 +1309,29 @@ class Stats {
    }
  }

-  void FinishedOps(DBWithColumnFamilies* db_with_cfh, DB* db, int64_t num_ops) {
+  void ResetLastOpTime() {
+    // Set to now to avoid latency from calls to SleepForMicroseconds
+    last_op_finish_ = FLAGS_env->NowMicros();
+  }
+
+  void FinishedOps(DBWithColumnFamilies* db_with_cfh, DB* db, int64_t num_ops,
+                   enum OperationType op_type = kOthers) {
    if (reporter_agent_) {
      reporter_agent_->ReportFinishedOps(num_ops);
    }
    if (FLAGS_histogram) {
-      double now = FLAGS_env->NowMicros();
-      double micros = now - last_op_finish_;
-      hist_.Add(micros);
+      uint64_t now = FLAGS_env->NowMicros();
+      uint64_t micros = now - last_op_finish_;
+
+      if (hist_.find(op_type) == hist_.end())
+      {
+        HistogramImpl hist_temp;
+        hist_.insert({op_type, hist_temp});
+      }
+      hist_[op_type].Add(micros);
+
      if (micros > 20000 && !FLAGS_stats_interval) {
-        fprintf(stderr, "long op: %.1f micros%30s\r", micros, "");
+        fprintf(stderr, "long op: %" PRIu64 " micros%30s\r", micros, "");
        fflush(stderr);
      }
      last_op_finish_ = now;
@@ -1261,7 +1349,7 @@ class Stats {
        else                            next_report_ += 100000;
        fprintf(stderr, "... finished %" PRIu64 " ops%30s\r", done_, "");
      } else {
-        double now = FLAGS_env->NowMicros();
+        uint64_t now = FLAGS_env->NowMicros();
        int64_t usecs_since_last = now - last_report_finish_;

        // Determine whether to print status where interval is either
@@ -1277,7 +1365,7 @@ class Stats {
          fprintf(stderr,
                  "%s ... thread %d: (%" PRIu64 ",%" PRIu64 ") ops and "
                  "(%.1f,%.1f) ops/second in (%.6f,%.6f) seconds\n",
-                  FLAGS_env->TimeToString((uint64_t) now/1000000).c_str(),
+                  FLAGS_env->TimeToString(now/1000000).c_str(),
                  id_,
                  done_ - last_report_done_, done_,
                  (done_ - last_report_done_) /
@@ -1370,7 +1458,11 @@ class Stats {
            (extra.empty() ? "" : " "),
            extra.c_str());
    if (FLAGS_histogram) {
-      fprintf(stdout, "Microseconds per op:\n%s\n", hist_.ToString().c_str());
+      for (auto it = hist_.begin(); it != hist_.end(); ++it) {
+        fprintf(stdout, "Microseconds per %s:\n%s\n",
+                OperationTypeString[it->first].c_str(),
+                it->second.ToString().c_str());
+      }
    }
    if (FLAGS_report_file_operations) {
      ReportFileOpEnv* env = static_cast<ReportFileOpEnv*>(FLAGS_env);
@@ -1427,7 +1519,7 @@ struct ThreadState {

 class Duration {
 public:
-  Duration(int max_seconds, int64_t max_ops, int64_t ops_per_stage = 0) {
+  Duration(uint64_t max_seconds, int64_t max_ops, int64_t ops_per_stage = 0) {
    max_seconds_ = max_seconds;
    max_ops_= max_ops;
    ops_per_stage_ = (ops_per_stage > 0) ? ops_per_stage : max_ops;
@@ -1444,8 +1536,8 @@ class Duration {
    if (max_seconds_) {
      // Recheck every appx 1000 ops (exact iff increment is factor of 1000)
      if ((ops_/1000) != ((ops_-increment)/1000)) {
-        double now = FLAGS_env->NowMicros();
-        return ((now - start_at_) / 1000000.0) >= max_seconds_;
+        uint64_t now = FLAGS_env->NowMicros();
+        return ((now - start_at_) / 1000000) >= max_seconds_;
      } else {
        return false;
      }
@@ -1455,11 +1547,11 @@ class Duration {
  }

 private:
-  int max_seconds_;
+  uint64_t max_seconds_;
  int64_t max_ops_;
  int64_t ops_per_stage_;
  int64_t ops_;
-  double start_at_;
+  uint64_t start_at_;
 };

 class Benchmark {
@@ -1543,7 +1635,8 @@ class Benchmark {
            (((FLAGS_key_size + FLAGS_value_size * FLAGS_compression_ratio)
              * num_)
             / 1048576.0));
-    fprintf(stdout, "Writes per second: %d\n", FLAGS_writes_per_second);
+    fprintf(stdout, "Write rate: %" PRIu64 " bytes/second\n",
+            FLAGS_benchmark_write_rate_limit);
    if (FLAGS_enable_numa) {
      fprintf(stderr, "Running in NUMA enabled mode.\n");
 #ifndef NUMA
@@ -1557,9 +1650,8 @@ class Benchmark {
 #endif
    }

-    const char* compression =
-        CompressionTypeToString(FLAGS_compression_type_e).c_str();
-    fprintf(stdout, "Compression: %s\n", compression);
+    auto compression = CompressionTypeToString(FLAGS_compression_type_e);
+    fprintf(stdout, "Compression: %s\n", compression.c_str());

    switch (FLAGS_rep_factory) {
      case kPrefixHash:
@@ -1580,7 +1672,7 @@ class Benchmark {
    }
    fprintf(stdout, "Perf Level: %d\n", FLAGS_perf_level);

-    PrintWarnings(compression);
+    PrintWarnings(compression.c_str());
    fprintf(stdout, "------------------------------------------------\n");
  }

@@ -1632,7 +1724,11 @@ class Benchmark {

 #if defined(__linux)
    time_t now = time(nullptr);
-    fprintf(stderr, "Date:       %s", ctime(&now));  // ctime() adds newline
+    char buf[52];
+    // Lint complains about ctime() usage, so replace it with ctime_r(). The
+    // requirement is to provide a buffer which is at least 26 bytes.
+    fprintf(stderr, "Date:       %s",
+            ctime_r(&now, buf));  // ctime_r() adds newline

    FILE* cpuinfo = fopen("/proc/cpuinfo", "r");
    if (cpuinfo != nullptr) {
@@ -1713,7 +1809,7 @@ class Benchmark {

    std::vector<std::string> files;
    FLAGS_env->GetChildren(FLAGS_db, &files);
-    for (unsigned int i = 0; i < files.size(); i++) {
+    for (size_t i = 0; i < files.size(); i++) {
      if (Slice(files[i]).starts_with("heap-")) {
        FLAGS_env->DeleteFile(FLAGS_db + "/" + files[i]);
      }
@@ -1940,9 +2036,11 @@ class Benchmark {
        method = &Benchmark::Compress;
      } else if (name == "uncompress") {
        method = &Benchmark::Uncompress;
+#ifndef ROCKSDB_LITE
      } else if (name == "randomtransaction") {
        method = &Benchmark::RandomTransaction;
        post_process_method = &Benchmark::RandomTransactionVerify;
+#endif  // ROCKSDB_LITE
      } else if (name == "randomreplacekeys") {
        fresh_db = true;
        method = &Benchmark::RandomReplaceKeys;
@@ -2109,7 +2207,7 @@ class Benchmark {
    uint32_t crc = 0;
    while (bytes < 500 * 1048576) {
      crc = crc32c::Value(data.data(), size);
-      thread->stats.FinishedOps(nullptr, nullptr, 1);
+      thread->stats.FinishedOps(nullptr, nullptr, 1, kCrc);
      bytes += size;
    }
    // Print so result is not dead
@@ -2128,7 +2226,7 @@ class Benchmark {
    unsigned int xxh32 = 0;
    while (bytes < 500 * 1048576) {
      xxh32 = XXH32(data.data(), size, 0);
-      thread->stats.FinishedOps(nullptr, nullptr, 1);
+      thread->stats.FinishedOps(nullptr, nullptr, 1, kHash);
      bytes += size;
    }
    // Print so result is not dead
@@ -2149,7 +2247,7 @@ class Benchmark {
        ptr = ap.load(std::memory_order_acquire);
      }
      count++;
-      thread->stats.FinishedOps(nullptr, nullptr, 1);
+      thread->stats.FinishedOps(nullptr, nullptr, 1, kOthers);
    }
    if (ptr == nullptr) exit(1); // Disable unused variable warning.
  }
@@ -2167,7 +2265,7 @@ class Benchmark {
      ok = CompressSlice(input, &compressed);
      produced += compressed.size();
      bytes += input.size();
-      thread->stats.FinishedOps(nullptr, nullptr, 1);
+      thread->stats.FinishedOps(nullptr, nullptr, 1, kCompress);
    }

    if (!ok) {
@@ -2192,12 +2290,19 @@ class Benchmark {
    while (ok && bytes < 1024 * 1048576) {
      char *uncompressed = nullptr;
      switch (FLAGS_compression_type_e) {
-      case rocksdb::kSnappyCompression:
-        // allocate here to make comparison fair
-        uncompressed = new char[input.size()];
-        ok = Snappy_Uncompress(compressed.data(), compressed.size(),
-                               uncompressed);
-        break;
+        case rocksdb::kSnappyCompression: {
+          // get size and allocate here to make comparison fair
+          size_t ulength = 0;
+          if (!Snappy_GetUncompressedLength(compressed.data(),
+                                            compressed.size(), &ulength)) {
+            ok = false;
+            break;
+          }
+          uncompressed = new char[ulength];
+          ok = Snappy_Uncompress(compressed.data(), compressed.size(),
+                                 uncompressed);
+          break;
+        }
      case rocksdb::kZlibCompression:
        uncompressed = Zlib_Uncompress(compressed.data(), compressed.size(),
                                       &decompress_size, 2);
@@ -2228,7 +2333,7 @@ class Benchmark {
      }
      delete[] uncompressed;
      bytes += input.size();
-      thread->stats.FinishedOps(nullptr, nullptr, 1);
+      thread->stats.FinishedOps(nullptr, nullptr, 1, kUncompress);
    }

    if (!ok) {
@@ -2275,6 +2380,8 @@ class Benchmark {
    options.new_table_reader_for_compaction_inputs =
        FLAGS_new_table_reader_for_compaction_inputs;
    options.compaction_readahead_size = FLAGS_compaction_readahead_size;
+    options.random_access_max_buffer_size = FLAGS_random_access_max_buffer_size;
+    options.writable_file_max_buffer_size = FLAGS_writable_file_max_buffer_size;
    options.statistics = dbstats;
    if (FLAGS_enable_io_prio) {
      FLAGS_env->LowerThreadPoolIOPriority(Env::LOW);
@@ -2288,8 +2395,7 @@ class Benchmark {
        fprintf(stderr, "Open flash device failed\n");
        exit(1);
      }
-      flashcache_aware_env_ =
-          std::move(NewFlashcacheAwareEnv(FLAGS_env, cachedev_fd_));
+      flashcache_aware_env_ = NewFlashcacheAwareEnv(FLAGS_env, cachedev_fd_);
      if (flashcache_aware_env_.get() == nullptr) {
        fprintf(stderr, "Failed to open flashcache device at %s\n",
                FLAGS_flashcache_dev.c_str());
@@ -2417,6 +2523,8 @@ class Benchmark {
      block_based_options.block_size = FLAGS_block_size;
      block_based_options.block_restart_interval = FLAGS_block_restart_interval;
      block_based_options.filter_policy = filter_policy_;
+      block_based_options.skip_table_builder_flush =
+          FLAGS_skip_table_builder_flush;
      block_based_options.format_version = 2;
      options.table_factory.reset(
          NewBlockBasedTableFactory(block_based_options));
@@ -2455,9 +2563,17 @@ class Benchmark {
    }
    options.soft_rate_limit = FLAGS_soft_rate_limit;
    options.hard_rate_limit = FLAGS_hard_rate_limit;
+    options.soft_pending_compaction_bytes_limit =
+        FLAGS_soft_pending_compaction_bytes_limit;
    options.hard_pending_compaction_bytes_limit =
        FLAGS_hard_pending_compaction_bytes_limit;
    options.delayed_write_rate = FLAGS_delayed_write_rate;
+    options.allow_concurrent_memtable_write =
+        FLAGS_allow_concurrent_memtable_write;
+    options.enable_write_thread_adaptive_yield =
+        FLAGS_enable_write_thread_adaptive_yield;
+    options.write_thread_max_yield_usec = FLAGS_write_thread_max_yield_usec;
+    options.write_thread_slow_yield_usec = FLAGS_write_thread_slow_yield_usec;
    options.rate_limit_delay_max_milliseconds =
      FLAGS_rate_limit_delay_max_milliseconds;
    options.table_cache_numshardbits = FLAGS_table_cache_numshardbits;
@@ -2518,10 +2634,12 @@ class Benchmark {
          NewGenericRateLimiter(FLAGS_rate_limiter_bytes_per_sec));
    }

+#ifndef ROCKSDB_LITE
    if (FLAGS_readonly && FLAGS_transaction_db) {
      fprintf(stderr, "Cannot use readonly flag with transaction_db\n");
      exit(1);
    }
+#endif  // ROCKSDB_LITE

    if (FLAGS_num_multi_db <= 1) {
      OpenDb(options, FLAGS_db, &db_);
@@ -2554,6 +2672,7 @@ class Benchmark {
        column_families.push_back(ColumnFamilyDescriptor(
              ColumnFamilyName(i), ColumnFamilyOptions(options)));
      }
+#ifndef ROCKSDB_LITE
      if (FLAGS_readonly) {
        s = DB::OpenForReadOnly(options, db_name, column_families,
            &db->cfh, &db->db);
@@ -2574,9 +2693,13 @@ class Benchmark {
      } else {
        s = DB::Open(options, db_name, column_families, &db->cfh, &db->db);
      }
+#else
+      s = DB::Open(options, db_name, column_families, &db->cfh, &db->db);
+#endif  // ROCKSDB_LITE
      db->cfh.resize(FLAGS_num_column_families);
      db->num_created = num_hot;
      db->num_hot = num_hot;
+#ifndef ROCKSDB_LITE
    } else if (FLAGS_readonly) {
      s = DB::OpenForReadOnly(options, db_name, &db->db);
    } else if (FLAGS_optimistic_transaction_db) {
@@ -2591,7 +2714,7 @@ class Benchmark {
      if (s.ok()) {
        db->db = ptr;
      }
-
+#endif  // ROCKSDB_LITE
    } else {
      s = DB::Open(options, db_name, &db->db);
    }
@@ -2725,14 +2848,22 @@ class Benchmark {
          }
        }
      }
+
      size_t id = thread->rand.Next() % num_key_gens;
      DBWithColumnFamilies* db_with_cfh = SelectDBWithCfh(id);
      batch.Clear();
+
+      if (thread->shared->write_rate_limiter.get() != nullptr) {
+        thread->shared->write_rate_limiter->Request(
+            entries_per_batch_ * (value_size_ + key_size_),
+            Env::IO_HIGH);
+        // Set time at which last op finished to Now() to hide latency and
+        // sleep from rate limiter. Also, do the check once per batch, not
+        // once per write.
+        thread->stats.ResetLastOpTime();
+      }
+
      for (int64_t j = 0; j < entries_per_batch_; j++) {
-        if (thread->shared->write_rate_limiter.get() != nullptr) {
-          thread->shared->write_rate_limiter->Request(value_size_ + key_size_,
-                                                      Env::IO_HIGH);
-        }
        int64_t rand_num = key_gens[id]->Next();
        GenerateKeyFromInt(rand_num, FLAGS_num, &key);
        if (FLAGS_num_column_families <= 1) {
@@ -2748,7 +2879,7 @@ class Benchmark {
      }
      s = db_with_cfh->db->Write(write_options_, &batch);
      thread->stats.FinishedOps(db_with_cfh, db_with_cfh->db,
-                                entries_per_batch_);
+                                entries_per_batch_, kWrite);
      if (!s.ok()) {
        fprintf(stderr, "put error: %s\n", s.ToString().c_str());
        exit(1);
@@ -2776,7 +2907,7 @@ class Benchmark {
    int64_t bytes = 0;
    for (iter->SeekToFirst(); i < reads_ && iter->Valid(); iter->Next()) {
      bytes += iter->key().size() + iter->value().size();
-      thread->stats.FinishedOps(nullptr, db, 1);
+      thread->stats.FinishedOps(nullptr, db, 1, kRead);
      ++i;
    }
    delete iter;
@@ -2799,7 +2930,7 @@ class Benchmark {
    int64_t bytes = 0;
    for (iter->SeekToLast(); i < reads_ && iter->Valid(); iter->Prev()) {
      bytes += iter->key().size() + iter->value().size();
-      thread->stats.FinishedOps(nullptr, db, 1);
+      thread->stats.FinishedOps(nullptr, db, 1, kRead);
      ++i;
    }
    delete iter;
@@ -2839,7 +2970,7 @@ class Benchmark {
          ++nonexist;
        }
      }
-      thread->stats.FinishedOps(nullptr, db, 100);
+      thread->stats.FinishedOps(nullptr, db, 100, kRead);
    } while (!duration.Done(100));

    char msg[100];
@@ -2907,7 +3038,7 @@ class Benchmark {
        fprintf(stderr, "Get returned an error: %s\n", s.ToString().c_str());
        abort();
      }
-      thread->stats.FinishedOps(db_with_cfh, db_with_cfh->db, 1);
+      thread->stats.FinishedOps(db_with_cfh, db_with_cfh->db, 1, kRead);
    }

    char msg[100];
@@ -2932,7 +3063,7 @@ class Benchmark {
    std::vector<std::unique_ptr<const char[]> > key_guards;
    std::vector<std::string> values(entries_per_batch_);
    while (static_cast<int64_t>(keys.size()) < entries_per_batch_) {
-      key_guards.push_back(std::move(std::unique_ptr<const char[]>()));
+      key_guards.push_back(std::unique_ptr<const char[]>());
      keys.push_back(AllocateKey(&key_guards.back()));
    }

@@ -2955,7 +3086,7 @@ class Benchmark {
          abort();
        }
      }
-      thread->stats.FinishedOps(nullptr, db, entries_per_batch_);
+      thread->stats.FinishedOps(nullptr, db, entries_per_batch_, kRead);
    }

    char msg[100];
@@ -2971,7 +3102,7 @@ class Benchmark {
      DB* db = SelectDB(thread);
      Iterator* iter = db->NewIterator(options);
      delete iter;
-      thread->stats.FinishedOps(nullptr, db, 1);
+      thread->stats.FinishedOps(nullptr, db, 1, kOthers);
    }
  }

@@ -2979,7 +3110,7 @@ class Benchmark {
    if (thread->tid > 0) {
      IteratorCreation(thread);
    } else {
-      BGWriter(thread, kPut);
+      BGWriter(thread, kWrite);
    }
  }

@@ -3048,7 +3179,7 @@ class Benchmark {
        assert(iter_to_use->status().ok());
      }

-      thread->stats.FinishedOps(&db_, db_.db, 1);
+      thread->stats.FinishedOps(&db_, db_.db, 1, kSeek);
    }
    delete single_iter;
    for (auto iter : multi_iters) {
@@ -3069,7 +3200,7 @@ class Benchmark {
    if (thread->tid > 0) {
      SeekRandom(thread);
    } else {
-      BGWriter(thread, kPut);
+      BGWriter(thread, kWrite);
    }
  }

@@ -3097,7 +3228,7 @@ class Benchmark {
        batch.Delete(key);
      }
      auto s = db->Write(write_options_, &batch);
-      thread->stats.FinishedOps(nullptr, db, entries_per_batch_);
+      thread->stats.FinishedOps(nullptr, db, entries_per_batch_, kDelete);
      if (!s.ok()) {
        fprintf(stderr, "del error: %s\n", s.ToString().c_str());
        exit(1);
@@ -3118,7 +3249,7 @@ class Benchmark {
    if (thread->tid > 0) {
      ReadRandom(thread);
    } else {
-      BGWriter(thread, kPut);
+      BGWriter(thread, kWrite);
    }
  }

@@ -3130,19 +3261,16 @@ class Benchmark {
    }
  }

-  void BGWriter(ThreadState* thread, enum PutOrMerge write_merge) {
+  void BGWriter(ThreadState* thread, enum OperationType write_merge) {
    // Special thread that keeps writing until other threads are done.
    RandomGenerator gen;
-    double last = FLAGS_env->NowMicros();
-    int writes_per_second_by_10 = 0;
-    int num_writes = 0;
    int64_t bytes = 0;

-    // --writes_per_second rate limit is enforced per 100 milliseconds
-    // intervals to avoid a burst of writes at the start of each second.
-
-    if (FLAGS_writes_per_second > 0)
-      writes_per_second_by_10 = FLAGS_writes_per_second / 10;
+    std::unique_ptr<RateLimiter> write_rate_limiter;
+    if (FLAGS_benchmark_write_rate_limit > 0) {
+      write_rate_limiter.reset(
+          NewGenericRateLimiter(FLAGS_benchmark_write_rate_limit));
+    }

    // Don't merge stats from this thread with the readers.
    thread->stats.SetExcludeFromMerge();
@@ -3163,7 +3291,7 @@ class Benchmark {
      GenerateKeyFromInt(thread->rand.Next() % FLAGS_num, FLAGS_num, &key);
      Status s;

-      if (write_merge == kPut) {
+      if (write_merge == kWrite) {
          s = db->Put(write_options_, key, gen.Generate(value_size_));
      } else {
          s = db->Merge(write_options_, key, gen.Generate(value_size_));
@@ -3174,20 +3302,12 @@ class Benchmark {
        exit(1);
      }
      bytes += key.size() + value_size_;
-      thread->stats.FinishedOps(&db_, db_.db, 1);
+      thread->stats.FinishedOps(&db_, db_.db, 1, kWrite);

-      ++num_writes;
-      if (writes_per_second_by_10 && num_writes >= writes_per_second_by_10) {
-        double now = FLAGS_env->NowMicros();
-        double usecs_since_last = now - last;
-
-        num_writes = 0;
-        last = now;
-
-        if (usecs_since_last < 100000.0) {
-          FLAGS_env->SleepForMicroseconds(100000.0 - usecs_since_last);
-          last = FLAGS_env->NowMicros();
-        }
+      if (FLAGS_benchmark_write_rate_limit > 0) {
+        write_rate_limiter->Request(
+            entries_per_batch_ * (value_size_ + key_size_),
+            Env::IO_HIGH);
      }
    }
    thread->stats.AddBytes(bytes);
@@ -3315,6 +3435,7 @@ class Benchmark {
        }
        get_weight--;
        gets_done++;
+        thread->stats.FinishedOps(&db_, db_.db, 1, kRead);
      } else if (put_weight > 0) {
        // then do all the corresponding number of puts
        // for all the gets we have done earlier
@@ -3325,6 +3446,7 @@ class Benchmark {
        }
        put_weight--;
        puts_done++;
+        thread->stats.FinishedOps(&db_, db_.db, 1, kWrite);
      } else if (delete_weight > 0) {
        Status s = DeleteMany(db, write_options_, key);
        if (!s.ok()) {
@@ -3333,9 +3455,8 @@ class Benchmark {
        }
        delete_weight--;
        deletes_done++;
+        thread->stats.FinishedOps(&db_, db_.db, 1, kDelete);
      }
-
-      thread->stats.FinishedOps(&db_, db_.db, 1);
    }
    char msg[100];
    snprintf(msg, sizeof(msg),
@@ -3382,6 +3503,7 @@ class Benchmark {
        }
        get_weight--;
        reads_done++;
+        thread->stats.FinishedOps(nullptr, db, 1, kRead);
      } else  if (put_weight > 0) {
        // then do all the corresponding number of puts
        // for all the gets we have done earlier
@@ -3392,8 +3514,8 @@ class Benchmark {
        }
        put_weight--;
        writes_done++;
+        thread->stats.FinishedOps(nullptr, db, 1, kWrite);
      }
-      thread->stats.FinishedOps(nullptr, db, 1);
    }
    char msg[100];
    snprintf(msg, sizeof(msg), "( reads:%" PRIu64 " writes:%" PRIu64 \
@@ -3435,7 +3557,7 @@ class Benchmark {
        exit(1);
      }
      bytes += key.size() + value_size_;
-      thread->stats.FinishedOps(nullptr, db, 1);
+      thread->stats.FinishedOps(nullptr, db, 1, kUpdate);
    }
    char msg[100];
    snprintf(msg, sizeof(msg),
@@ -3490,7 +3612,7 @@ class Benchmark {
        exit(1);
      }
      bytes += key.size() + value.size();
-      thread->stats.FinishedOps(nullptr, db, 1);
+      thread->stats.FinishedOps(nullptr, db, 1, kUpdate);
    }

    char msg[100];
@@ -3528,7 +3650,7 @@ class Benchmark {
        exit(1);
      }
      bytes += key.size() + value_size_;
-      thread->stats.FinishedOps(nullptr, db, 1);
+      thread->stats.FinishedOps(nullptr, db, 1, kMerge);
    }

    // Print some statistics
@@ -3570,9 +3692,8 @@ class Benchmark {
          fprintf(stderr, "merge error: %s\n", s.ToString().c_str());
          exit(1);
        }
-
        num_merges++;
-
+        thread->stats.FinishedOps(nullptr, db, 1, kMerge);
      } else {
        Status s = db->Get(options, key, &value);
        if (value.length() > max_length)
@@ -3585,12 +3706,9 @@ class Benchmark {
        } else if (!s.IsNotFound()) {
          num_hits++;
        }
-
        num_gets++;
-
+        thread->stats.FinishedOps(nullptr, db, 1, kRead);
      }
-
-      thread->stats.FinishedOps(nullptr, db, 1);
    }

    char msg[100];
@@ -3617,7 +3735,7 @@ class Benchmark {
      GenerateKeyFromInt(i, FLAGS_num, &key);
      iter->Seek(key);
      assert(iter->Valid() && iter->key() == key);
-      thread->stats.FinishedOps(nullptr, db, 1);
+      thread->stats.FinishedOps(nullptr, db, 1, kSeek);

      for (int j = 0; j < FLAGS_seek_nexts && i + 1 < FLAGS_num; ++j) {
        if (!FLAGS_reverse_iterator) {
@@ -3627,15 +3745,16 @@ class Benchmark {
        }
        GenerateKeyFromInt(++i, FLAGS_num, &key);
        assert(iter->Valid() && iter->key() == key);
-        thread->stats.FinishedOps(nullptr, db, 1);
+        thread->stats.FinishedOps(nullptr, db, 1, kSeek);
      }

      iter->Seek(key);
      assert(iter->Valid() && iter->key() == key);
-      thread->stats.FinishedOps(nullptr, db, 1);
+      thread->stats.FinishedOps(nullptr, db, 1, kSeek);
    }
  }

+#ifndef ROCKSDB_LITE
  // This benchmark stress tests Transactions.  For a given --duration (or
  // total number of --writes, a Transaction will perform a read-modify-write
  // to increment the value of a key in each of N(--transaction-sets) sets of
@@ -3785,15 +3904,11 @@ class Benchmark {
        }
      }

-      if (txn) {
-        delete txn;
-      }
-      if (batch) {
-        delete batch;
-      }
+      delete txn;
+      delete batch;

      if (!failed) {
-        thread->stats.FinishedOps(nullptr, db, 1);
+        thread->stats.FinishedOps(nullptr, db, 1, kOthers);
      }

      transactions_done++;
@@ -3868,6 +3983,7 @@ class Benchmark {

    fprintf(stdout, "RandomTransactionVerify Success!\n");
  }
+#endif  // ROCKSDB_LITE

  // Writes and deletes random keys without overwriting keys.
  //
@@ -3918,7 +4034,7 @@ class Benchmark {
        exit(1);
      }

-      thread->stats.FinishedOps(nullptr, db, 1);
+      thread->stats.FinishedOps(nullptr, db, 1, kOthers);
    }

    char msg[200];
@@ -3971,7 +4087,7 @@ int main(int argc, char** argv) {

  std::vector<std::string> fanout = rocksdb::StringSplit(
      FLAGS_max_bytes_for_level_multiplier_additional, ',');
-  for (unsigned int j= 0; j < fanout.size(); j++) {
+  for (size_t j = 0; j < fanout.size(); j++) {
    FLAGS_max_bytes_for_level_multiplier_additional_v.push_back(
 #ifndef CYGWIN
        std::stoi(fanout[j]));
@@ -7,8 +7,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file. See the AUTHORS file for names of contributors.

+#include "db/db_test_util.h"
 #include "port/stack_trace.h"
-#include "util/db_test_util.h"

 namespace rocksdb {

@@ -47,6 +47,24 @@ class DeleteFilter : public CompactionFilter {
  virtual const char* Name() const override { return "DeleteFilter"; }
 };

+class DeleteISFilter : public CompactionFilter {
+ public:
+  virtual bool Filter(int level, const Slice& key, const Slice& value,
+                      std::string* new_value,
+                      bool* value_changed) const override {
+    cfilter_count++;
+    int i = std::stoi(key.ToString());
+    if (i > 5 && i <= 105) {
+      return true;
+    }
+    return false;
+  }
+
+  virtual bool IgnoreSnapshots() const override { return true; }
+
+  virtual const char* Name() const override { return "DeleteFilter"; }
+};
+
 class DelayFilter : public CompactionFilter {
 public:
  explicit DelayFilter(DBTestBase* d) : db_test(d) {}
@@ -97,8 +115,11 @@ class ChangeFilter : public CompactionFilter {

 class KeepFilterFactory : public CompactionFilterFactory {
 public:
-  explicit KeepFilterFactory(bool check_context = false)
-      : check_context_(check_context) {}
+  explicit KeepFilterFactory(bool check_context = false,
+                             bool check_context_cf_id = false)
+      : check_context_(check_context),
+        check_context_cf_id_(check_context_cf_id),
+        compaction_filter_created_(false) {}

  virtual std::unique_ptr<CompactionFilter> CreateCompactionFilter(
      const CompactionFilter::Context& context) override {
@@ -106,13 +127,22 @@ class KeepFilterFactory : public CompactionFilterFactory {
      EXPECT_EQ(expect_full_compaction_.load(), context.is_full_compaction);
      EXPECT_EQ(expect_manual_compaction_.load(), context.is_manual_compaction);
    }
+    if (check_context_cf_id_) {
+      EXPECT_EQ(expect_cf_id_.load(), context.column_family_id);
+    }
+    compaction_filter_created_ = true;
    return std::unique_ptr<CompactionFilter>(new KeepFilter());
  }

+  bool compaction_filter_created() const { return compaction_filter_created_; }
+
  virtual const char* Name() const override { return "KeepFilterFactory"; }
  bool check_context_;
+  bool check_context_cf_id_;
  std::atomic_bool expect_full_compaction_;
  std::atomic_bool expect_manual_compaction_;
+  std::atomic<uint32_t> expect_cf_id_;
+  bool compaction_filter_created_;
 };

 class DeleteFilterFactory : public CompactionFilterFactory {
@@ -129,6 +159,21 @@ class DeleteFilterFactory : public CompactionFilterFactory {
  virtual const char* Name() const override { return "DeleteFilterFactory"; }
 };

+// Delete Filter Factory which ignores snapshots
+class DeleteISFilterFactory : public CompactionFilterFactory {
+ public:
+  virtual std::unique_ptr<CompactionFilter> CreateCompactionFilter(
+      const CompactionFilter::Context& context) override {
+    if (context.is_manual_compaction) {
+      return std::unique_ptr<CompactionFilter>(new DeleteISFilter());
+    } else {
+      return std::unique_ptr<CompactionFilter>(nullptr);
+    }
+  }
+
+  virtual const char* Name() const override { return "DeleteFilterFactory"; }
+};
+
 class DelayFilterFactory : public CompactionFilterFactory {
 public:
  explicit DelayFilterFactory(DBTestBase* d) : db_test(d) {}
@@ -174,6 +219,7 @@ class ChangeFilterFactory : public CompactionFilterFactory {
  virtual const char* Name() const override { return "ChangeFilterFactory"; }
 };

+#ifndef ROCKSDB_LITE
 TEST_F(DBTestCompactionFilter, CompactionFilter) {
  Options options = CurrentOptions();
  options.max_open_files = -1;
@@ -216,7 +262,7 @@ TEST_F(DBTestCompactionFilter, CompactionFilter) {
  Arena arena;
  {
    ScopedArenaIterator iter(
-        dbfull()->TEST_NewInternalIterator(&arena, handles_[1]));
+        dbfull()->NewInternalIterator(&arena, handles_[1]));
    iter->SeekToFirst();
    ASSERT_OK(iter->status());
    while (iter->Valid()) {
@@ -304,7 +350,7 @@ TEST_F(DBTestCompactionFilter, CompactionFilter) {
  count = 0;
  {
    ScopedArenaIterator iter(
-        dbfull()->TEST_NewInternalIterator(&arena, handles_[1]));
+        dbfull()->NewInternalIterator(&arena, handles_[1]));
    iter->SeekToFirst();
    ASSERT_OK(iter->status());
    while (iter->Valid()) {
@@ -350,6 +396,7 @@ TEST_F(DBTestCompactionFilter, CompactionFilterDeletesAll) {

  delete itr;
 }
+#endif  // ROCKSDB_LITE

 TEST_F(DBTestCompactionFilter, CompactionFilterWithValueChange) {
  do {
@@ -481,8 +528,9 @@ TEST_F(DBTestCompactionFilter, CompactionFilterWithMergeOperator) {
  ASSERT_EQ(newvalue, four);
 }

+#ifndef ROCKSDB_LITE
 TEST_F(DBTestCompactionFilter, CompactionFilterContextManual) {
-  KeepFilterFactory* filter = new KeepFilterFactory();
+  KeepFilterFactory* filter = new KeepFilterFactory(true, true);

  Options options = CurrentOptions();
  options.compaction_style = kCompactionStyleUniversal;
@@ -504,22 +552,24 @@ TEST_F(DBTestCompactionFilter, CompactionFilterContextManual) {
    // be triggered.
    num_keys_per_file /= 2;
  }
+  dbfull()->TEST_WaitForCompact();

  // Force a manual compaction
  cfilter_count = 0;
  filter->expect_manual_compaction_.store(true);
-  filter->expect_full_compaction_.store(false);  // Manual compaction always
-                                                 // set this flag.
+  filter->expect_full_compaction_.store(true);
+  filter->expect_cf_id_.store(0);
  dbfull()->CompactRange(CompactRangeOptions(), nullptr, nullptr);
  ASSERT_EQ(cfilter_count, 700);
  ASSERT_EQ(NumSortedRuns(0), 1);
+  ASSERT_TRUE(filter->compaction_filter_created());

  // Verify total number of keys is correct after manual compaction.
  {
    int count = 0;
    int total = 0;
    Arena arena;
-    ScopedArenaIterator iter(dbfull()->TEST_NewInternalIterator(&arena));
+    ScopedArenaIterator iter(dbfull()->NewInternalIterator(&arena));
    iter->SeekToFirst();
    ASSERT_OK(iter->status());
    while (iter->Valid()) {
@@ -533,10 +583,41 @@ TEST_F(DBTestCompactionFilter, CompactionFilterContextManual) {
      iter->Next();
    }
    ASSERT_EQ(total, 700);
-    ASSERT_EQ(count, 1);
+    ASSERT_EQ(count, 2);
  }
 }
+#endif  // ROCKSDB_LITE

+TEST_F(DBTestCompactionFilter, CompactionFilterContextCfId) {
+  KeepFilterFactory* filter = new KeepFilterFactory(false, true);
+  filter->expect_cf_id_.store(1);
+
+  Options options = CurrentOptions();
+  options.compaction_filter_factory.reset(filter);
+  options.compression = kNoCompression;
+  options.level0_file_num_compaction_trigger = 2;
+  CreateAndReopenWithCF({"pikachu"}, options);
+
+  int num_keys_per_file = 400;
+  for (int j = 0; j < 3; j++) {
+    // Write several keys.
+    const std::string value(10, 'x');
+    for (int i = 0; i < num_keys_per_file; i++) {
+      char key[100];
+      snprintf(key, sizeof(key), "B%08d%02d", i, j);
+      Put(1, key, value);
+    }
+    Flush(1);
+    // Make sure next file is much smaller so automatic compaction will not
+    // be triggered.
+    num_keys_per_file /= 2;
+  }
+  dbfull()->TEST_WaitForCompact();
+
+  ASSERT_TRUE(filter->compaction_filter_created());
+}
+
+#ifndef ROCKSDB_LITE
 // Compaction filters should only be applied to records that are newer than the
 // latest snapshot. This test inserts records and applies a delete filter.
 TEST_F(DBTestCompactionFilter, CompactionFilterSnapshot) {
@@ -573,14 +654,73 @@ TEST_F(DBTestCompactionFilter, CompactionFilterSnapshot) {
  ASSERT_EQ(0U, CountLiveFiles());
 }

+// Compaction filters should only be applied to records that are newer than the
+// latest snapshot. However, if the compaction filter asks to ignore snapshots
+// records newer than the snapshot will also be processed
+TEST_F(DBTestCompactionFilter, CompactionFilterIgnoreSnapshot) {
+  std::string five = ToString(5);
+  Options options;
+  options.compaction_filter_factory = std::make_shared<DeleteISFilterFactory>();
+  options.disable_auto_compactions = true;
+  options.create_if_missing = true;
+  options = CurrentOptions(options);
+  DestroyAndReopen(options);
+
+  // Put some data.
+  const Snapshot* snapshot = nullptr;
+  for (int table = 0; table < 4; ++table) {
+    for (int i = 0; i < 10; ++i) {
+      Put(ToString(table * 100 + i), "val");
+    }
+    Flush();
+
+    if (table == 0) {
+      snapshot = db_->GetSnapshot();
+    }
+  }
+  assert(snapshot != nullptr);
+
+  cfilter_count = 0;
+  ASSERT_OK(db_->CompactRange(CompactRangeOptions(), nullptr, nullptr));
+  // The filter should delete 40 records.
+  ASSERT_EQ(40U, cfilter_count);
+
+  {
+    // Scan the entire database as of the snapshot to ensure
+    // that nothing is left
+    ReadOptions read_options;
+    read_options.snapshot = snapshot;
+    std::unique_ptr<Iterator> iter(db_->NewIterator(read_options));
+    iter->SeekToFirst();
+    int count = 0;
+    while (iter->Valid()) {
+      count++;
+      iter->Next();
+    }
+    ASSERT_EQ(count, 6);
+    read_options.snapshot = 0;
+    std::unique_ptr<Iterator> iter1(db_->NewIterator(read_options));
+    iter1->SeekToFirst();
+    count = 0;
+    while (iter1->Valid()) {
+      count++;
+      iter1->Next();
+    }
+    // We have deleted 10 keys from 40 using the compaction filter
+    //  Keys 6-9 before the snapshot and 100-105 after the snapshot
+    ASSERT_EQ(count, 30);
+  }
+
+  // Release the snapshot and compact again -> now all records should be
+  // removed.
+  db_->ReleaseSnapshot(snapshot);
+}
+#endif  // ROCKSDB_LITE
+
 }  // namespace rocksdb

 int main(int argc, char** argv) {
-#if !(defined NDEBUG) || !defined(OS_WIN)
  rocksdb::port::InstallStackTraceHandler();
  ::testing::InitGoogleTest(&argc, argv);
  return RUN_ALL_TESTS();
-#else
-  return 0;
-#endif
 }
@@ -7,26 +7,28 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file. See the AUTHORS file for names of contributors.

+#include "db/db_test_util.h"
 #include "port/stack_trace.h"
 #include "rocksdb/experimental.h"
-#include "util/db_test_util.h"
+#include "rocksdb/utilities/convenience.h"
 #include "util/sync_point.h"
 namespace rocksdb {

 // SYNC_POINT is not supported in released Windows mode.
-#if !(defined NDEBUG) || !defined(OS_WIN)
-
+#if !defined(ROCKSDB_LITE)

 class DBCompactionTest : public DBTestBase {
 public:
  DBCompactionTest() : DBTestBase("/db_compaction_test") {}
 };

-class DBCompactionTestWithParam : public DBTestBase,
-                                public testing::WithParamInterface<uint32_t> {
+class DBCompactionTestWithParam
+    : public DBTestBase,
+      public testing::WithParamInterface<std::tuple<uint32_t, bool>> {
 public:
  DBCompactionTestWithParam() : DBTestBase("/db_compaction_test") {
-    max_subcompactions_ = GetParam();
+    max_subcompactions_ = std::get<0>(GetParam());
+    exclusive_manual_compaction_ = std::get<1>(GetParam());
  }

  // Required if inheriting from testing::WithParamInterface<>
@@ -34,6 +36,7 @@ class DBCompactionTestWithParam : public DBTestBase,
  static void TearDownTestCase() {}

  uint32_t max_subcompactions_;
+  bool exclusive_manual_compaction_;
 };

 namespace {
@@ -66,6 +69,32 @@ class OnFileDeletionListener : public EventListener {
  std::string expected_file_name_;
 };

+class FlushedFileCollector : public EventListener {
+ public:
+  FlushedFileCollector() {}
+  ~FlushedFileCollector() {}
+
+  virtual void OnFlushCompleted(DB* db, const FlushJobInfo& info) override {
+    std::lock_guard<std::mutex> lock(mutex_);
+    flushed_files_.push_back(info.file_path);
+  }
+
+  std::vector<std::string> GetFlushedFiles() {
+    std::lock_guard<std::mutex> lock(mutex_);
+    std::vector<std::string> result;
+    for (auto fname : flushed_files_) {
+      result.push_back(fname);
+    }
+    return result;
+  }
+
+  void ClearFlushedFiles() { flushed_files_.clear(); }
+
+ private:
+  std::vector<std::string> flushed_files_;
+  std::mutex mutex_;
+};
+
 static const int kCDTValueSize = 1000;
 static const int kCDTKeysPerBuffer = 4;
 static const int kCDTNumLevels = 8;
@@ -161,7 +190,7 @@ const SstFileMetaData* PickFileRandomly(
      auto result = rand->Uniform(file_id);
      return &(level_meta.files[result]);
    }
-    file_id -= level_meta.files.size();
+    file_id -= static_cast<uint32_t>(level_meta.files.size());
  }
  assert(false);
  return nullptr;
@@ -240,9 +269,12 @@ TEST_F(DBCompactionTest, SkipStatsUpdateTest) {
  env_->random_file_open_counter_.store(0);
  Reopen(options);

-  // As stats-update is disabled, we expect a very low
-  // number of random file open.
-  ASSERT_LT(env_->random_file_open_counter_.load(), 5);
+  // As stats-update is disabled, we expect a very low number of
+  // random file open.
+  // Note that this number must be changed accordingly if we change
+  // the number of files needed to be opened in the DB::Open process.
+  const int kMaxFileOpenCount = 10;
+  ASSERT_LT(env_->random_file_open_counter_.load(), kMaxFileOpenCount);

  // Repeat the reopen process, but this time we enable
  // stats-update.
@@ -252,7 +284,7 @@ TEST_F(DBCompactionTest, SkipStatsUpdateTest) {

  // Since we do a normal stats update on db-open, there
  // will be more random open files.
-  ASSERT_GT(env_->random_file_open_counter_.load(), 5);
+  ASSERT_GT(env_->random_file_open_counter_.load(), kMaxFileOpenCount);
 }

 TEST_F(DBCompactionTest, TestTableReaderForCompaction) {
@@ -459,12 +491,15 @@ TEST_F(DBCompactionTest, DisableStatsUpdateReopen) {


 TEST_P(DBCompactionTestWithParam, CompactionTrigger) {
+  const int kNumKeysPerFile = 100;
+
  Options options;
  options.write_buffer_size = 110 << 10;  // 110KB
  options.arena_block_size = 4 << 10;
  options.num_levels = 3;
  options.level0_file_num_compaction_trigger = 3;
  options.max_subcompactions = max_subcompactions_;
+  options.memtable_factory.reset(new SpecialSkipListFactory(kNumKeysPerFile));
  options = CurrentOptions(options);
  CreateAndReopenWithCF({"pikachu"}, options);

@@ -474,20 +509,24 @@ TEST_P(DBCompactionTestWithParam, CompactionTrigger) {
       num++) {
    std::vector<std::string> values;
    // Write 100KB (100 values, each 1K)
-    for (int i = 0; i < 100; i++) {
+    for (int i = 0; i < kNumKeysPerFile; i++) {
      values.push_back(RandomString(&rnd, 990));
      ASSERT_OK(Put(1, Key(i), values[i]));
    }
+    // put extra key to trigger flush
+    ASSERT_OK(Put(1, "", ""));
    dbfull()->TEST_WaitForFlushMemTable(handles_[1]);
    ASSERT_EQ(NumTableFilesAtLevel(0, 1), num + 1);
  }

  // generate one more file in level-0, and should trigger level-0 compaction
  std::vector<std::string> values;
-  for (int i = 0; i < 100; i++) {
+  for (int i = 0; i < kNumKeysPerFile; i++) {
    values.push_back(RandomString(&rnd, 990));
    ASSERT_OK(Put(1, Key(i), values[i]));
  }
+  // put extra key to trigger flush
+  ASSERT_OK(Put(1, "", ""));
  dbfull()->TEST_WaitForCompact();

  ASSERT_EQ(NumTableFilesAtLevel(0, 1), 0);
@@ -551,6 +590,61 @@ TEST_F(DBCompactionTest, MinorCompactionsHappen) {
  } while (ChangeCompactOptions());
 }

+TEST_F(DBCompactionTest, ZeroSeqIdCompaction) {
+  Options options;
+  options.compaction_style = kCompactionStyleLevel;
+  options.level0_file_num_compaction_trigger = 3;
+
+  FlushedFileCollector* collector = new FlushedFileCollector();
+  options.listeners.emplace_back(collector);
+
+  // compaction options
+  CompactionOptions compact_opt;
+  compact_opt.compression = kNoCompression;
+  compact_opt.output_file_size_limit = 4096;
+  const size_t key_len =
+    static_cast<size_t>(compact_opt.output_file_size_limit) / 5;
+
+  options = CurrentOptions(options);
+  DestroyAndReopen(options);
+
+  std::vector<const Snapshot*> snaps;
+
+  // create first file and flush to l0
+  for (auto& key : {"1", "2", "3", "3", "3", "3"}) {
+    Put(key, std::string(key_len, 'A'));
+    snaps.push_back(dbfull()->GetSnapshot());
+  }
+  Flush();
+  dbfull()->TEST_WaitForFlushMemTable();
+
+  // create second file and flush to l0
+  for (auto& key : {"3", "4", "5", "6", "7", "8"}) {
+    Put(key, std::string(key_len, 'A'));
+    snaps.push_back(dbfull()->GetSnapshot());
+  }
+  Flush();
+  dbfull()->TEST_WaitForFlushMemTable();
+
+  // move both files down to l1
+  dbfull()->CompactFiles(compact_opt, collector->GetFlushedFiles(), 1);
+
+  // release snap so that first instance of key(3) can have seqId=0
+  for (auto snap : snaps) {
+    dbfull()->ReleaseSnapshot(snap);
+  }
+
+  // create 3 files in l0 so to trigger compaction
+  for (int i = 0; i < options.level0_file_num_compaction_trigger; i++) {
+    Put("2", std::string(1, 'A'));
+    Flush();
+    dbfull()->TEST_WaitForFlushMemTable();
+  }
+
+  dbfull()->TEST_WaitForCompact();
+  ASSERT_OK(Put("", ""));
+}
+
 // Check that writes done during a memtable compaction are recovered
 // if the database is shutdown during the memtable compaction.
 TEST_F(DBCompactionTest, RecoverDuringMemtableCompaction) {
@@ -608,8 +702,11 @@ TEST_P(DBCompactionTestWithParam, TrivialMoveOneFile) {
  ASSERT_EQ(metadata.size(), 1U);
  LiveFileMetaData level0_file = metadata[0];  // L0 file meta

+  CompactRangeOptions cro;
+  cro.exclusive_manual_compaction = exclusive_manual_compaction_;
+
  // Compaction will initiate a trivial move from L0 to L1
-  dbfull()->CompactRange(CompactRangeOptions(), nullptr, nullptr);
+  dbfull()->CompactRange(cro, nullptr, nullptr);

  // File moved From L0 to L1
  ASSERT_EQ(NumTableFilesAtLevel(0, 0), 0);  // 0 files in L0
@@ -661,7 +758,7 @@ TEST_P(DBCompactionTestWithParam, TrivialMoveNonOverlappingFiles) {

  Random rnd(301);
  std::map<int32_t, std::string> values;
-  for (uint32_t i = 0; i < ranges.size(); i++) {
+  for (size_t i = 0; i < ranges.size(); i++) {
    for (int32_t j = ranges[i].first; j <= ranges[i].second; j++) {
      values[j] = RandomString(&rnd, value_size);
      ASSERT_OK(Put(Key(j), values[j]));
@@ -673,14 +770,17 @@ TEST_P(DBCompactionTestWithParam, TrivialMoveNonOverlappingFiles) {
  ASSERT_EQ(level0_files, ranges.size());    // Multiple files in L0
  ASSERT_EQ(NumTableFilesAtLevel(1, 0), 0);  // No files in L1

+  CompactRangeOptions cro;
+  cro.exclusive_manual_compaction = exclusive_manual_compaction_;
+
  // Since data is non-overlapping we expect compaction to initiate
  // a trivial move
-  db_->CompactRange(CompactRangeOptions(), nullptr, nullptr);
+  db_->CompactRange(cro, nullptr, nullptr);
  // We expect that all the files were trivially moved from L0 to L1
  ASSERT_EQ(NumTableFilesAtLevel(0, 0), 0);
  ASSERT_EQ(NumTableFilesAtLevel(1, 0) /* level1_files */, level0_files);

-  for (uint32_t i = 0; i < ranges.size(); i++) {
+  for (size_t i = 0; i < ranges.size(); i++) {
    for (int32_t j = ranges[i].first; j <= ranges[i].second; j++) {
      ASSERT_EQ(Get(Key(j)), values[j]);
    }
@@ -704,7 +804,7 @@ TEST_P(DBCompactionTestWithParam, TrivialMoveNonOverlappingFiles) {
    {500, 560},  // this range overlap with the next one
    {551, 599},
  };
-  for (uint32_t i = 0; i < ranges.size(); i++) {
+  for (size_t i = 0; i < ranges.size(); i++) {
    for (int32_t j = ranges[i].first; j <= ranges[i].second; j++) {
      values[j] = RandomString(&rnd, value_size);
      ASSERT_OK(Put(Key(j), values[j]));
@@ -712,9 +812,9 @@ TEST_P(DBCompactionTestWithParam, TrivialMoveNonOverlappingFiles) {
    ASSERT_OK(Flush());
  }

-  db_->CompactRange(CompactRangeOptions(), nullptr, nullptr);
+  db_->CompactRange(cro, nullptr, nullptr);

-  for (uint32_t i = 0; i < ranges.size(); i++) {
+  for (size_t i = 0; i < ranges.size(); i++) {
    for (int32_t j = ranges[i].first; j <= ranges[i].second; j++) {
      ASSERT_EQ(Get(Key(j)), values[j]);
    }
@@ -768,6 +868,7 @@ TEST_P(DBCompactionTestWithParam, TrivialMoveTargetLevel) {
  CompactRangeOptions compact_options;
  compact_options.change_level = true;
  compact_options.target_level = 6;
+  compact_options.exclusive_manual_compaction = exclusive_manual_compaction_;
  ASSERT_OK(db_->CompactRange(compact_options, nullptr, nullptr));
  // 2 files in L6
  ASSERT_EQ("0,0,0,0,0,0,2", FilesPerLevel(0));
@@ -783,6 +884,382 @@ TEST_P(DBCompactionTestWithParam, TrivialMoveTargetLevel) {
  }
 }

+TEST_P(DBCompactionTestWithParam, ManualCompactionPartial) {
+  int32_t trivial_move = 0;
+  int32_t non_trivial_move = 0;
+  rocksdb::SyncPoint::GetInstance()->SetCallBack(
+      "DBImpl::BackgroundCompaction:TrivialMove",
+      [&](void* arg) { trivial_move++; });
+  rocksdb::SyncPoint::GetInstance()->SetCallBack(
+      "DBImpl::BackgroundCompaction:NonTrivial",
+      [&](void* arg) { non_trivial_move++; });
+  bool first = true;
+  bool second = true;
+  rocksdb::SyncPoint::GetInstance()->LoadDependency(
+      {{"DBCompaction::ManualPartial:4", "DBCompaction::ManualPartial:1"},
+       {"DBCompaction::ManualPartial:2", "DBCompaction::ManualPartial:3"}});
+  rocksdb::SyncPoint::GetInstance()->SetCallBack(
+      "DBImpl::BackgroundCompaction:NonTrivial:AfterRun", [&](void* arg) {
+        if (first) {
+          TEST_SYNC_POINT("DBCompaction::ManualPartial:4");
+          first = false;
+          TEST_SYNC_POINT("DBCompaction::ManualPartial:3");
+        } else if (second) {
+          TEST_SYNC_POINT("DBCompaction::ManualPartial:2");
+        }
+      });
+
+  rocksdb::SyncPoint::GetInstance()->EnableProcessing();
+
+  Options options = CurrentOptions();
+  options.write_buffer_size = 10 * 1024 * 1024;
+  options.num_levels = 7;
+  options.max_subcompactions = max_subcompactions_;
+  options.level0_file_num_compaction_trigger = 3;
+  options.max_background_compactions = 3;
+  options.target_file_size_base = 1 << 23;  // 8 MB
+
+  DestroyAndReopen(options);
+  int32_t value_size = 10 * 1024;  // 10 KB
+
+  // Add 2 non-overlapping files
+  Random rnd(301);
+  std::map<int32_t, std::string> values;
+
+  // file 1 [0 => 100]
+  for (int32_t i = 0; i < 100; i++) {
+    values[i] = RandomString(&rnd, value_size);
+    ASSERT_OK(Put(Key(i), values[i]));
+  }
+  ASSERT_OK(Flush());
+
+  // file 2 [100 => 300]
+  for (int32_t i = 100; i < 300; i++) {
+    values[i] = RandomString(&rnd, value_size);
+    ASSERT_OK(Put(Key(i), values[i]));
+  }
+  ASSERT_OK(Flush());
+
+  // 2 files in L0
+  ASSERT_EQ("2", FilesPerLevel(0));
+  CompactRangeOptions compact_options;
+  compact_options.change_level = true;
+  compact_options.target_level = 6;
+  compact_options.exclusive_manual_compaction = exclusive_manual_compaction_;
+  // Trivial move the two non-overlapping files to level 6
+  ASSERT_OK(db_->CompactRange(compact_options, nullptr, nullptr));
+  // 2 files in L6
+  ASSERT_EQ("0,0,0,0,0,0,2", FilesPerLevel(0));
+
+  ASSERT_EQ(trivial_move, 1);
+  ASSERT_EQ(non_trivial_move, 0);
+
+  // file 3 [ 0 => 200]
+  for (int32_t i = 0; i < 200; i++) {
+    values[i] = RandomString(&rnd, value_size);
+    ASSERT_OK(Put(Key(i), values[i]));
+  }
+  ASSERT_OK(Flush());
+
+  // 1 files in L0
+  ASSERT_EQ("1,0,0,0,0,0,2", FilesPerLevel(0));
+  ASSERT_OK(dbfull()->TEST_CompactRange(0, nullptr, nullptr, nullptr, false));
+  ASSERT_OK(dbfull()->TEST_CompactRange(1, nullptr, nullptr, nullptr, false));
+  ASSERT_OK(dbfull()->TEST_CompactRange(2, nullptr, nullptr, nullptr, false));
+  ASSERT_OK(dbfull()->TEST_CompactRange(3, nullptr, nullptr, nullptr, false));
+  ASSERT_OK(dbfull()->TEST_CompactRange(4, nullptr, nullptr, nullptr, false));
+  // 2 files in L6, 1 file in L5
+  ASSERT_EQ("0,0,0,0,0,1,2", FilesPerLevel(0));
+
+  ASSERT_EQ(trivial_move, 6);
+  ASSERT_EQ(non_trivial_move, 0);
+
+  std::thread threads([&] {
+    compact_options.change_level = false;
+    compact_options.exclusive_manual_compaction = false;
+    std::string begin_string = Key(0);
+    std::string end_string = Key(199);
+    Slice begin(begin_string);
+    Slice end(end_string);
+    ASSERT_OK(db_->CompactRange(compact_options, &begin, &end));
+  });
+
+  TEST_SYNC_POINT("DBCompaction::ManualPartial:1");
+  // file 4 [300 => 400)
+  for (int32_t i = 300; i <= 400; i++) {
+    values[i] = RandomString(&rnd, value_size);
+    ASSERT_OK(Put(Key(i), values[i]));
+  }
+  ASSERT_OK(Flush());
+
+  // file 5 [400 => 500)
+  for (int32_t i = 400; i <= 500; i++) {
+    values[i] = RandomString(&rnd, value_size);
+    ASSERT_OK(Put(Key(i), values[i]));
+  }
+  ASSERT_OK(Flush());
+
+  // file 6 [500 => 600)
+  for (int32_t i = 500; i <= 600; i++) {
+    values[i] = RandomString(&rnd, value_size);
+    ASSERT_OK(Put(Key(i), values[i]));
+  }
+  ASSERT_OK(Flush());
+
+  // 3 files in L0
+  ASSERT_EQ("3,0,0,0,0,1,2", FilesPerLevel(0));
+  // 1 file in L6, 1 file in L1
+  dbfull()->TEST_WaitForFlushMemTable();
+  dbfull()->TEST_WaitForCompact();
+  ASSERT_EQ("0,1,0,0,0,0,1", FilesPerLevel(0));
+  threads.join();
+
+  for (int32_t i = 0; i < 600; i++) {
+    ASSERT_EQ(Get(Key(i)), values[i]);
+  }
+}
+
+TEST_F(DBCompactionTest, ManualPartialFill) {
+  int32_t trivial_move = 0;
+  int32_t non_trivial_move = 0;
+  rocksdb::SyncPoint::GetInstance()->SetCallBack(
+      "DBImpl::BackgroundCompaction:TrivialMove",
+      [&](void* arg) { trivial_move++; });
+  rocksdb::SyncPoint::GetInstance()->SetCallBack(
+      "DBImpl::BackgroundCompaction:NonTrivial",
+      [&](void* arg) { non_trivial_move++; });
+  bool first = true;
+  bool second = true;
+  rocksdb::SyncPoint::GetInstance()->LoadDependency(
+      {{"DBCompaction::PartialFill:4", "DBCompaction::PartialFill:1"},
+       {"DBCompaction::PartialFill:2", "DBCompaction::PartialFill:3"}});
+  rocksdb::SyncPoint::GetInstance()->SetCallBack(
+      "DBImpl::BackgroundCompaction:NonTrivial:AfterRun", [&](void* arg) {
+        if (first) {
+          TEST_SYNC_POINT("DBCompaction::PartialFill:4");
+          first = false;
+          TEST_SYNC_POINT("DBCompaction::PartialFill:3");
+        } else if (second) {
+        }
+      });
+
+  rocksdb::SyncPoint::GetInstance()->EnableProcessing();
+
+  Options options = CurrentOptions();
+  options.write_buffer_size = 10 * 1024 * 1024;
+  options.max_bytes_for_level_multiplier = 2;
+  options.num_levels = 4;
+  options.level0_file_num_compaction_trigger = 3;
+  options.max_background_compactions = 3;
+
+  DestroyAndReopen(options);
+  int32_t value_size = 10 * 1024;  // 10 KB
+
+  // Add 2 non-overlapping files
+  Random rnd(301);
+  std::map<int32_t, std::string> values;
+
+  // file 1 [0 => 100]
+  for (int32_t i = 0; i < 100; i++) {
+    values[i] = RandomString(&rnd, value_size);
+    ASSERT_OK(Put(Key(i), values[i]));
+  }
+  ASSERT_OK(Flush());
+
+  // file 2 [100 => 300]
+  for (int32_t i = 100; i < 300; i++) {
+    values[i] = RandomString(&rnd, value_size);
+    ASSERT_OK(Put(Key(i), values[i]));
+  }
+  ASSERT_OK(Flush());
+
+  // 2 files in L0
+  ASSERT_EQ("2", FilesPerLevel(0));
+  CompactRangeOptions compact_options;
+  compact_options.change_level = true;
+  compact_options.target_level = 2;
+  ASSERT_OK(db_->CompactRange(compact_options, nullptr, nullptr));
+  // 2 files in L2
+  ASSERT_EQ("0,0,2", FilesPerLevel(0));
+
+  ASSERT_EQ(trivial_move, 1);
+  ASSERT_EQ(non_trivial_move, 0);
+
+  // file 3 [ 0 => 200]
+  for (int32_t i = 0; i < 200; i++) {
+    values[i] = RandomString(&rnd, value_size);
+    ASSERT_OK(Put(Key(i), values[i]));
+  }
+  ASSERT_OK(Flush());
+
+  // 2 files in L2, 1 in L0
+  ASSERT_EQ("1,0,2", FilesPerLevel(0));
+  ASSERT_OK(dbfull()->TEST_CompactRange(0, nullptr, nullptr, nullptr, false));
+  // 2 files in L2, 1 in L1
+  ASSERT_EQ("0,1,2", FilesPerLevel(0));
+
+  ASSERT_EQ(trivial_move, 2);
+  ASSERT_EQ(non_trivial_move, 0);
+
+  std::thread threads([&] {
+    compact_options.change_level = false;
+    compact_options.exclusive_manual_compaction = false;
+    std::string begin_string = Key(0);
+    std::string end_string = Key(199);
+    Slice begin(begin_string);
+    Slice end(end_string);
+    ASSERT_OK(db_->CompactRange(compact_options, &begin, &end));
+  });
+
+  TEST_SYNC_POINT("DBCompaction::PartialFill:1");
+  // Many files 4 [300 => 4300)
+  for (int32_t i = 0; i <= 5; i++) {
+    for (int32_t j = 300; j < 4300; j++) {
+      if (j == 2300) {
+        ASSERT_OK(Flush());
+        dbfull()->TEST_WaitForFlushMemTable();
+      }
+      values[j] = RandomString(&rnd, value_size);
+      ASSERT_OK(Put(Key(j), values[j]));
+    }
+  }
+
+  // Verify level sizes
+  uint64_t target_size = 4 * options.max_bytes_for_level_base;
+  for (int32_t i = 1; i < options.num_levels; i++) {
+    ASSERT_LE(SizeAtLevel(i), target_size);
+    target_size *= options.max_bytes_for_level_multiplier;
+  }
+
+  TEST_SYNC_POINT("DBCompaction::PartialFill:2");
+  dbfull()->TEST_WaitForFlushMemTable();
+  dbfull()->TEST_WaitForCompact();
+  threads.join();
+
+  for (int32_t i = 0; i < 4300; i++) {
+    ASSERT_EQ(Get(Key(i)), values[i]);
+  }
+}
+
+TEST_F(DBCompactionTest, DeleteFileRange) {
+  Options options = CurrentOptions();
+  options.write_buffer_size = 10 * 1024 * 1024;
+  options.max_bytes_for_level_multiplier = 2;
+  options.num_levels = 4;
+  options.level0_file_num_compaction_trigger = 3;
+  options.max_background_compactions = 3;
+
+  DestroyAndReopen(options);
+  int32_t value_size = 10 * 1024;  // 10 KB
+
+  // Add 2 non-overlapping files
+  Random rnd(301);
+  std::map<int32_t, std::string> values;
+
+  // file 1 [0 => 100]
+  for (int32_t i = 0; i < 100; i++) {
+    values[i] = RandomString(&rnd, value_size);
+    ASSERT_OK(Put(Key(i), values[i]));
+  }
+  ASSERT_OK(Flush());
+
+  // file 2 [100 => 300]
+  for (int32_t i = 100; i < 300; i++) {
+    values[i] = RandomString(&rnd, value_size);
+    ASSERT_OK(Put(Key(i), values[i]));
+  }
+  ASSERT_OK(Flush());
+
+  // 2 files in L0
+  ASSERT_EQ("2", FilesPerLevel(0));
+  CompactRangeOptions compact_options;
+  compact_options.change_level = true;
+  compact_options.target_level = 2;
+  ASSERT_OK(db_->CompactRange(compact_options, nullptr, nullptr));
+  // 2 files in L2
+  ASSERT_EQ("0,0,2", FilesPerLevel(0));
+
+  // file 3 [ 0 => 200]
+  for (int32_t i = 0; i < 200; i++) {
+    values[i] = RandomString(&rnd, value_size);
+    ASSERT_OK(Put(Key(i), values[i]));
+  }
+  ASSERT_OK(Flush());
+
+  // Many files 4 [300 => 4300)
+  for (int32_t i = 0; i <= 5; i++) {
+    for (int32_t j = 300; j < 4300; j++) {
+      if (j == 2300) {
+        ASSERT_OK(Flush());
+        dbfull()->TEST_WaitForFlushMemTable();
+      }
+      values[j] = RandomString(&rnd, value_size);
+      ASSERT_OK(Put(Key(j), values[j]));
+    }
+  }
+  ASSERT_OK(Flush());
+  dbfull()->TEST_WaitForFlushMemTable();
+  dbfull()->TEST_WaitForCompact();
+
+  // Verify level sizes
+  uint64_t target_size = 4 * options.max_bytes_for_level_base;
+  for (int32_t i = 1; i < options.num_levels; i++) {
+    ASSERT_LE(SizeAtLevel(i), target_size);
+    target_size *= options.max_bytes_for_level_multiplier;
+  }
+
+  size_t old_num_files = CountFiles();
+  std::string begin_string = Key(1000);
+  std::string end_string = Key(2000);
+  Slice begin(begin_string);
+  Slice end(end_string);
+  ASSERT_OK(DeleteFilesInRange(db_, db_->DefaultColumnFamily(), &begin, &end));
+
+  int32_t deleted_count = 0;
+  for (int32_t i = 0; i < 4300; i++) {
+    if (i < 1000 || i > 2000) {
+      ASSERT_EQ(Get(Key(i)), values[i]);
+    } else {
+      ReadOptions roptions;
+      std::string result;
+      Status s = db_->Get(roptions, Key(i), &result);
+      ASSERT_TRUE(s.IsNotFound() || s.ok());
+      if (s.IsNotFound()) {
+        deleted_count++;
+      }
+    }
+  }
+  ASSERT_GT(deleted_count, 0);
+  begin_string = Key(5000);
+  end_string = Key(6000);
+  Slice begin1(begin_string);
+  Slice end1(end_string);
+  // Try deleting files in range which contain no keys
+  ASSERT_OK(
+      DeleteFilesInRange(db_, db_->DefaultColumnFamily(), &begin1, &end1));
+
+  // Push data from level 0 to level 1 to force all data to be deleted
+  // Note that we don't delete level 0 files
+  compact_options.change_level = true;
+  compact_options.target_level = 1;
+  ASSERT_OK(dbfull()->TEST_CompactRange(0, nullptr, nullptr));
+
+  ASSERT_OK(
+      DeleteFilesInRange(db_, db_->DefaultColumnFamily(), nullptr, nullptr));
+
+  int32_t deleted_count2 = 0;
+  for (int32_t i = 0; i < 4300; i++) {
+    ReadOptions roptions;
+    std::string result;
+    Status s = db_->Get(roptions, Key(i), &result);
+    ASSERT_TRUE(s.IsNotFound());
+    deleted_count2++;
+  }
+  ASSERT_GT(deleted_count2, deleted_count);
+  size_t new_num_files = CountFiles();
+  ASSERT_GT(old_num_files, new_num_files);
+}
+
 TEST_P(DBCompactionTestWithParam, TrivialMoveToLastLevelWithFiles) {
  int32_t trivial_move = 0;
  int32_t non_trivial_move = 0;
@@ -816,6 +1293,7 @@ TEST_P(DBCompactionTestWithParam, TrivialMoveToLastLevelWithFiles) {
  CompactRangeOptions compact_options;
  compact_options.change_level = true;
  compact_options.target_level = 3;
+  compact_options.exclusive_manual_compaction = exclusive_manual_compaction_;
  ASSERT_OK(db_->CompactRange(compact_options, nullptr, nullptr));
  ASSERT_EQ("0,0,0,1", FilesPerLevel(0));
  ASSERT_EQ(trivial_move, 1);
@@ -829,8 +1307,10 @@ TEST_P(DBCompactionTestWithParam, TrivialMoveToLastLevelWithFiles) {
  ASSERT_OK(Flush());

  ASSERT_EQ("1,0,0,1", FilesPerLevel(0));
+  CompactRangeOptions cro;
+  cro.exclusive_manual_compaction = exclusive_manual_compaction_;
  // Compaction will do L0=>L1 L1=>L2 L2=>L3 (3 trivial moves)
-  ASSERT_OK(db_->CompactRange(CompactRangeOptions(), nullptr, nullptr));
+  ASSERT_OK(db_->CompactRange(cro, nullptr, nullptr));
  ASSERT_EQ("0,0,0,2", FilesPerLevel(0));
  ASSERT_EQ(trivial_move, 4);
  ASSERT_EQ(non_trivial_move, 0);
@@ -847,6 +1327,8 @@ TEST_P(DBCompactionTestWithParam, LevelCompactionThirdPath) {
  options.db_paths.emplace_back(dbname_, 500 * 1024);
  options.db_paths.emplace_back(dbname_ + "_2", 4 * 1024 * 1024);
  options.db_paths.emplace_back(dbname_ + "_3", 1024 * 1024 * 1024);
+  options.memtable_factory.reset(
+      new SpecialSkipListFactory(KNumKeysByGenerateNewFile - 1));
  options.compaction_style = kCompactionStyleLevel;
  options.write_buffer_size = 110 << 10;  // 110KB
  options.arena_block_size = 4 << 10;
@@ -962,6 +1444,8 @@ TEST_P(DBCompactionTestWithParam, LevelCompactionPathUse) {
  options.db_paths.emplace_back(dbname_, 500 * 1024);
  options.db_paths.emplace_back(dbname_ + "_2", 4 * 1024 * 1024);
  options.db_paths.emplace_back(dbname_ + "_3", 1024 * 1024 * 1024);
+  options.memtable_factory.reset(
+      new SpecialSkipListFactory(KNumKeysByGenerateNewFile - 1));
  options.compaction_style = kCompactionStyleLevel;
  options.write_buffer_size = 110 << 10;  // 110KB
  options.arena_block_size = 4 << 10;
@@ -1130,6 +1614,7 @@ TEST_P(DBCompactionTestWithParam, ConvertCompactionStyle) {
  compact_options.target_level = 0;
  compact_options.bottommost_level_compaction =
      BottommostLevelCompaction::kForce;
+  compact_options.exclusive_manual_compaction = exclusive_manual_compaction_;
  dbfull()->CompactRange(compact_options, handles_[1], nullptr, nullptr);

  // Only 1 file in L0
@@ -1228,6 +1713,7 @@ TEST_F(DBCompactionTest, L0_CompactionBug_Issue44_b) {
 TEST_P(DBCompactionTestWithParam, ManualCompaction) {
  Options options = CurrentOptions();
  options.max_subcompactions = max_subcompactions_;
+  options.statistics = rocksdb::CreateDBStatistics();
  CreateAndReopenWithCF({"pikachu"}, options);

  // iter - 0 with 7 levels
@@ -1259,7 +1745,16 @@ TEST_P(DBCompactionTestWithParam, ManualCompaction) {
    // Compact all
    MakeTables(1, "a", "z", 1);
    ASSERT_EQ("1,0,2", FilesPerLevel(1));
-    db_->CompactRange(CompactRangeOptions(), handles_[1], nullptr, nullptr);
+
+    uint64_t prev_block_cache_add =
+        options.statistics->getTickerCount(BLOCK_CACHE_ADD);
+    CompactRangeOptions cro;
+    cro.exclusive_manual_compaction = exclusive_manual_compaction_;
+    db_->CompactRange(cro, handles_[1], nullptr, nullptr);
+    // Verify manual compaction doesn't fill block cache
+    ASSERT_EQ(prev_block_cache_add,
+              options.statistics->getTickerCount(BLOCK_CACHE_ADD));
+
    ASSERT_EQ("0,0,1", FilesPerLevel(1));

    if (iter == 0) {
@@ -1267,6 +1762,7 @@ TEST_P(DBCompactionTestWithParam, ManualCompaction) {
      options.max_background_flushes = 0;
      options.num_levels = 3;
      options.create_if_missing = true;
+      options.statistics = rocksdb::CreateDBStatistics();
      DestroyAndReopen(options);
      CreateAndReopenWithCF({"pikachu"}, options);
    }
@@ -1333,6 +1829,7 @@ TEST_P(DBCompactionTestWithParam, ManualLevelCompactionOutputPathId) {
    ASSERT_EQ(1, GetSstFileCount(options.db_paths[0].path));
    CompactRangeOptions compact_options;
    compact_options.target_path_id = 1;
+    compact_options.exclusive_manual_compaction = exclusive_manual_compaction_;
    db_->CompactRange(compact_options, handles_[1], nullptr, nullptr);

    ASSERT_EQ("0,1", FilesPerLevel(1));
@@ -1593,6 +2090,8 @@ TEST_P(DBCompactionTestWithParam, CompressLevelCompaction) {
    return;
  }
  Options options = CurrentOptions();
+  options.memtable_factory.reset(
+      new SpecialSkipListFactory(KNumKeysByGenerateNewFile - 1));
  options.compaction_style = kCompactionStyleLevel;
  options.write_buffer_size = 110 << 10;  // 110KB
  options.arena_block_size = 4 << 10;
@@ -1843,12 +2342,62 @@ TEST_P(DBCompactionTestWithParam, ForceBottommostLevelCompaction) {
 }

 INSTANTIATE_TEST_CASE_P(DBCompactionTestWithParam, DBCompactionTestWithParam,
-                        ::testing::Values(1, 4));
-#endif  // !(defined NDEBUG) || !defined(OS_WIN)
+                        ::testing::Values(std::make_tuple(1, true),
+                                          std::make_tuple(1, false),
+                                          std::make_tuple(4, true),
+                                          std::make_tuple(4, false)));
+
+class CompactionPriTest : public DBTestBase,
+                          public testing::WithParamInterface<uint32_t> {
+ public:
+  CompactionPriTest() : DBTestBase("/compaction_pri_test") {
+    compaction_pri_ = GetParam();
+  }
+
+  // Required if inheriting from testing::WithParamInterface<>
+  static void SetUpTestCase() {}
+  static void TearDownTestCase() {}
+
+  uint32_t compaction_pri_;
+};
+
+TEST_P(CompactionPriTest, Test) {
+  Options options;
+  options.write_buffer_size = 16 * 1024;
+  options.compaction_pri = static_cast<CompactionPri>(compaction_pri_);
+  options.hard_pending_compaction_bytes_limit = 256 * 1024;
+  options.max_bytes_for_level_base = 64 * 1024;
+  options.max_bytes_for_level_multiplier = 4;
+  options.compression = kNoCompression;
+  options = CurrentOptions(options);
+  DestroyAndReopen(options);
+
+  Random rnd(301);
+  const int kNKeys = 5000;
+  int keys[kNKeys];
+  for (int i = 0; i < kNKeys; i++) {
+    keys[i] = i;
+  }
+  std::random_shuffle(std::begin(keys), std::end(keys));
+
+  for (int i = 0; i < kNKeys; i++) {
+    ASSERT_OK(Put(Key(keys[i]), RandomString(&rnd, 102)));
+  }
+
+  dbfull()->TEST_WaitForCompact();
+  for (int i = 0; i < kNKeys; i++) {
+    ASSERT_NE("NOT_FOUND", Get(Key(i)));
+  }
+}
+
+INSTANTIATE_TEST_CASE_P(CompactionPriTest, CompactionPriTest,
+                        ::testing::Values(0, 1, 2));
+
+#endif // !defined(ROCKSDB_LITE)
 }  // namespace rocksdb

 int main(int argc, char** argv) {
-#if !(defined NDEBUG) || !defined(OS_WIN)
+#if !defined(ROCKSDB_LITE)
  rocksdb::port::InstallStackTraceHandler();
  ::testing::InitGoogleTest(&argc, argv);
  return RUN_ALL_TESTS();
@@ -10,10 +10,10 @@
 // Introduction of SyncPoint effectively disabled building and running this test
 // in Release build.
 // which is a pity, it is a good test
-#if !(defined NDEBUG) || !defined(OS_WIN)
+#if !defined(ROCKSDB_LITE)

+#include "db/db_test_util.h"
 #include "port/stack_trace.h"
-#include "util/db_test_util.h"

 namespace rocksdb {
 class DBTestDynamicLevel : public DBTestBase {
@@ -484,10 +484,10 @@ TEST_F(DBTestDynamicLevel, MigrateToDynamicLevelMaxBytesBase) {
 }
 }  // namespace rocksdb

-#endif  // !(defined NDEBUG) || !defined(OS_WIN)
+#endif  // !defined(ROCKSDB_LITE)

 int main(int argc, char** argv) {
-#if !(defined NDEBUG) || !defined(OS_WIN)
+#if !defined(ROCKSDB_LITE)
  rocksdb::port::InstallStackTraceHandler();
  ::testing::InitGoogleTest(&argc, argv);
  return RUN_ALL_TESTS();
@@ -36,11 +36,11 @@
 #include "rocksdb/env.h"
 #include "rocksdb/memtablerep.h"
 #include "rocksdb/transaction_log.h"
+#include "table/scoped_arena_iterator.h"
 #include "util/autovector.h"
 #include "util/event_logger.h"
 #include "util/hash.h"
 #include "util/instrumented_mutex.h"
-#include "util/scoped_arena_iterator.h"
 #include "util/stop_watch.h"
 #include "util/thread_local.h"

@@ -122,6 +122,9 @@ class DBImpl : public DB {
  using DB::GetIntProperty;
  virtual bool GetIntProperty(ColumnFamilyHandle* column_family,
                              const Slice& property, uint64_t* value) override;
+  using DB::GetAggregatedIntProperty;
+  virtual bool GetAggregatedIntProperty(const Slice& property,
+                                        uint64_t* aggregated_value) override;
  using DB::GetApproximateSizes;
  virtual void GetApproximateSizes(ColumnFamilyHandle* column_family,
                                   const Range* range, int n, uint64_t* sizes,
@@ -141,6 +144,9 @@ class DBImpl : public DB {
  virtual Status PauseBackgroundWork() override;
  virtual Status ContinueBackgroundWork() override;

+  virtual Status EnableAutoCompaction(
+      const std::vector<ColumnFamilyHandle*>& column_family_handles) override;
+
  using DB::SetOptions;
  Status SetOptions(
      ColumnFamilyHandle* column_family,
@@ -182,6 +188,8 @@ class DBImpl : public DB {
      const TransactionLogIterator::ReadOptions&
          read_options = TransactionLogIterator::ReadOptions()) override;
  virtual Status DeleteFile(std::string name) override;
+  Status DeleteFilesInRange(ColumnFamilyHandle* column_family,
+                            const Slice* begin, const Slice* end);

  virtual void GetLiveFilesMetaData(
      std::vector<LiveFileMetaData>* metadata) override;
@@ -220,13 +228,30 @@ class DBImpl : public DB {
                                                   bool include_history);

  // For a given key, check to see if there are any records for this key
-  // in the memtables, including memtable history.
-
-  // On success, *seq will contain the sequence number for the
-  // latest such change or kMaxSequenceNumber if no records were present.
-  // Returns OK on success, other status on error reading memtables.
-  Status GetLatestSequenceForKeyFromMemtable(SuperVersion* sv, const Slice& key,
-                                             SequenceNumber* seq);
+  // in the memtables, including memtable history.  If cache_only is false,
+  // SST files will also be checked.
+  //
+  // If a key is found, *found_record_for_key will be set to true and
+  // *seq will will be set to the stored sequence number for the latest
+  // operation on this key or kMaxSequenceNumber if unknown.
+  // If no key is found, *found_record_for_key will be set to false.
+  //
+  // Note: If cache_only=false, it is possible for *seq to be set to 0 if
+  // the sequence number has been cleared from the record.  If the caller is
+  // holding an active db snapshot, we know the missing sequence must be less
+  // than the snapshot's sequence number (sequence numbers are only cleared
+  // when there are no earlier active snapshots).
+  //
+  // If NotFound is returned and found_record_for_key is set to false, then no
+  // record for this key was found.  If the caller is holding an active db
+  // snapshot, we know that no key could have existing after this snapshot
+  // (since we do not compact keys that have an earlier snapshot).
+  //
+  // Returns OK or NotFound on success,
+  // other status on unexpected error.
+  Status GetLatestSequenceForKey(SuperVersion* sv, const Slice& key,
+                                 bool cache_only, SequenceNumber* seq,
+                                 bool* found_record_for_key);

  using DB::AddFile;
  virtual Status AddFile(ColumnFamilyHandle* column_family,
@@ -237,6 +262,12 @@ class DBImpl : public DB {

 #endif  // ROCKSDB_LITE

+  // Similar to GetSnapshot(), but also lets the db know that this snapshot
+  // will be used for transaction write-conflict checking.  The DB can then
+  // make sure not to compact any keys that would prevent a write-conflict from
+  // being detected.
+  const Snapshot* GetSnapshotForWriteConflictBoundary();
+
  // checks if all live files exist on file system and that their file sizes
  // match to our in-memory records
  virtual Status CheckConsistency();
@@ -246,9 +277,16 @@ class DBImpl : public DB {
  Status RunManualCompaction(ColumnFamilyData* cfd, int input_level,
                             int output_level, uint32_t output_path_id,
                             const Slice* begin, const Slice* end,
+                             bool exclusive,
                             bool disallow_trivial_move = false);

-#ifndef ROCKSDB_LITE
+  // Return an internal iterator over the current state of the database.
+  // The keys of this iterator are internal keys (see format.h).
+  // The returned iterator should be deleted when no longer needed.
+  InternalIterator* NewInternalIterator(
+      Arena* arena, ColumnFamilyHandle* column_family = nullptr);
+
+#ifndef NDEBUG
  // Extra methods (for testing) that are not in the public DB interface
  // Implemented in db_impl_debug.cc

@@ -266,12 +304,6 @@ class DBImpl : public DB {
  // Wait for any compaction
  Status TEST_WaitForCompact();

-  // Return an internal iterator over the current state of the database.
-  // The keys of this iterator are internal keys (see format.h).
-  // The returned iterator should be deleted when no longer needed.
-  Iterator* TEST_NewInternalIterator(
-      Arena* arena, ColumnFamilyHandle* column_family = nullptr);
-
  // Return the maximum overlapping data (in bytes) at next level for any
  // file at a level >= 1.
  int64_t TEST_MaxNextLevelOverlappingBytes(ColumnFamilyHandle* column_family =
@@ -305,7 +337,15 @@ class DBImpl : public DB {

  uint64_t TEST_LogfileNumber();

-#endif  // ROCKSDB_LITE
+  // Returns column family name to ImmutableCFOptions map.
+  Status TEST_GetAllImmutableCFOptions(
+      std::unordered_map<std::string, const ImmutableCFOptions*>* iopts_map);
+
+  Cache* TEST_table_cache() { return table_cache_.get(); }
+
+  WriteController& TEST_write_controler() { return write_controller_; }
+
+#endif  // NDEBUG

  // Returns the list of live files in 'live' and the list
  // of all files in the filesystem in 'candidate_files'.
@@ -363,6 +403,20 @@ class DBImpl : public DB {
  // Same as above, should called without mutex held and not on write thread.
  ColumnFamilyHandle* GetColumnFamilyHandleUnlocked(uint32_t column_family_id);

+  // Returns the number of currently running flushes.
+  // REQUIREMENT: mutex_ must be held when calling this function.
+  int num_running_flushes() {
+    mutex_.AssertHeld();
+    return num_running_flushes_;
+  }
+
+  // Returns the number of currently running compactions.
+  // REQUIREMENT: mutex_ must be held when calling this function.
+  int num_running_compactions() {
+    mutex_.AssertHeld();
+    return num_running_compactions_;
+  }
+
 protected:
  Env* const env_;
  const std::string dbname_;
@@ -370,12 +424,25 @@ class DBImpl : public DB {
  const DBOptions db_options_;
  Statistics* stats_;

-  Iterator* NewInternalIterator(const ReadOptions&, ColumnFamilyData* cfd,
-                                SuperVersion* super_version, Arena* arena);
+  InternalIterator* NewInternalIterator(const ReadOptions&,
+                                        ColumnFamilyData* cfd,
+                                        SuperVersion* super_version,
+                                        Arena* arena);
+
+  // Except in DB::Open(), WriteOptionsFile can only be called when:
+  // 1. WriteThread::Writer::EnterUnbatched() is used.
+  // 2. db_mutex is held
+  Status WriteOptionsFile();
+
+  // The following two functions can only be called when:
+  // 1. WriteThread::Writer::EnterUnbatched() is used.
+  // 2. db_mutex is NOT held
+  Status RenameTempFileToOptionsFile(const std::string& file_name);
+  Status DeleteObsoleteOptionsFiles();

  void NotifyOnFlushCompleted(ColumnFamilyData* cfd, FileMetaData* file_meta,
                              const MutableCFOptions& mutable_cf_options,
-                              int job_id);
+                              int job_id, TableProperties prop);

  void NotifyOnCompactionCompleted(ColumnFamilyData* cfd,
                                   Compaction *c, const Status &st,
@@ -488,12 +555,13 @@ class DBImpl : public DB {
  void MaybeScheduleFlushOrCompaction();
  void SchedulePendingFlush(ColumnFamilyData* cfd);
  void SchedulePendingCompaction(ColumnFamilyData* cfd);
-  static void BGWorkCompaction(void* db);
+  static void BGWorkCompaction(void* arg);
  static void BGWorkFlush(void* db);
-  void BackgroundCallCompaction();
+  static void UnscheduleCallback(void* arg);
+  void BackgroundCallCompaction(void* arg);
  void BackgroundCallFlush();
  Status BackgroundCompaction(bool* madeProgress, JobContext* job_context,
-                              LogBuffer* log_buffer);
+                              LogBuffer* log_buffer, void* m = 0);
  Status BackgroundFlush(bool* madeProgress, JobContext* job_context,
                         LogBuffer* log_buffer);

@@ -521,18 +589,25 @@ class DBImpl : public DB {
  // helper function to call after some of the logs_ were synced
  void MarkLogsSynced(uint64_t up_to, bool synced_dir, const Status& status);

+  const Snapshot* GetSnapshotImpl(bool is_write_conflict_boundary);
+
  // table_cache_ provides its own synchronization
  std::shared_ptr<Cache> table_cache_;

  // Lock over the persistent DB state.  Non-nullptr iff successfully acquired.
  FileLock* db_lock_;

+  // The mutex for options file related operations.
+  // NOTE: should never acquire options_file_mutex_ and mutex_ at the
+  //       same time.
+  InstrumentedMutex options_files_mutex_;
  // State below is protected by mutex_
  InstrumentedMutex mutex_;
+
  std::atomic<bool> shutting_down_;
  // This condition variable is signaled on these conditions:
  // * whenever bg_compaction_scheduled_ goes down to 0
-  // * if bg_manual_only_ > 0, whenever a compaction finishes, even if it hasn't
+  // * if AnyManualCompaction, whenever a compaction finishes, even if it hasn't
  // made any progress
  // * whenever a compaction made any progress
  // * whenever bg_flush_scheduled_ value decreases (i.e. whenever a flush is
@@ -540,6 +615,8 @@ class DBImpl : public DB {
  // * whenever there is an error in background flush or compaction
  InstrumentedCondVar bg_cv_;
  uint64_t logfile_number_;
+  std::deque<uint64_t>
+      log_recycle_files;  // a list of log files that we can recycle
  bool log_dir_synced_;
  bool log_empty_;
  ColumnFamilyHandleImpl* default_cf_handle_;
@@ -685,29 +762,40 @@ class DBImpl : public DB {
  // count how many background compactions are running or have been scheduled
  int bg_compaction_scheduled_;

-  // If non-zero, MaybeScheduleFlushOrCompaction() will only schedule manual
-  // compactions (if manual_compaction_ is not null). This mechanism enables
-  // manual compactions to wait until all other compactions are finished.
-  int bg_manual_only_;
+  // stores the number of compactions are currently running
+  int num_running_compactions_;

  // number of background memtable flush jobs, submitted to the HIGH pool
  int bg_flush_scheduled_;

+  // stores the number of flushes are currently running
+  int num_running_flushes_;
+
  // Information for a manual compaction
  struct ManualCompaction {
    ColumnFamilyData* cfd;
    int input_level;
    int output_level;
    uint32_t output_path_id;
-    bool done;
    Status status;
+    bool done;
    bool in_progress;             // compaction request being processed?
+    bool incomplete;              // only part of requested range compacted
+    bool exclusive;               // current behavior of only one manual
+    bool disallow_trivial_move;   // Force actual compaction to run
    const InternalKey* begin;     // nullptr means beginning of key range
    const InternalKey* end;       // nullptr means end of key range
+    InternalKey* manual_end;      // how far we are compacting
    InternalKey tmp_storage;      // Used to keep track of compaction progress
-    bool disallow_trivial_move;   // Force actual compaction to run
+    InternalKey tmp_storage1;     // Used to keep track of compaction progress
+    Compaction* compaction;
+  };
+  std::deque<ManualCompaction*> manual_compaction_dequeue_;
+
+  struct CompactionArg {
+    DBImpl* db;
+    ManualCompaction* m;
  };
-  ManualCompaction* manual_compaction_;

  // Have we encountered a background error in paranoid mode?
  Status bg_error_;
@@ -788,6 +876,10 @@ class DBImpl : public DB {
  virtual Status GetPropertiesOfAllTables(ColumnFamilyHandle* column_family,
                                          TablePropertiesCollection* props)
      override;
+  virtual Status GetPropertiesOfTablesInRange(
+      ColumnFamilyHandle* column_family, const Range* range, std::size_t n,
+      TablePropertiesCollection* props) override;
+
 #endif  // ROCKSDB_LITE

  // Function that Get and KeyMayExist call with no_io true or false
@@ -796,9 +888,18 @@ class DBImpl : public DB {
                 const Slice& key, std::string* value,
                 bool* value_found = nullptr);

-  bool GetIntPropertyInternal(ColumnFamilyHandle* column_family,
+  bool GetIntPropertyInternal(ColumnFamilyData* cfd,
                              DBPropertyType property_type,
-                              bool need_out_of_mutex, uint64_t* value);
+                              bool need_out_of_mutex, bool is_locked,
+                              uint64_t* value);
+
+  bool HasPendingManualCompaction();
+  bool HasExclusiveManualCompaction();
+  void AddManualCompaction(ManualCompaction* m);
+  void RemoveManualCompaction(ManualCompaction* m);
+  bool ShouldntRunManualCompaction(ManualCompaction* m);
+  bool HaveManualCompaction(ColumnFamilyData* cfd);
+  bool MCOverlap(ManualCompaction* m, ManualCompaction* m1);
 };

 // Sanitize db options.  The caller should delete result.info_log if
@@ -7,7 +7,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file. See the AUTHORS file for names of contributors.

-#ifndef ROCKSDB_LITE
+#ifndef NDEBUG

 #include "db/db_impl.h"
 #include "util/thread_status_updater.h"
@@ -19,23 +19,6 @@ uint64_t DBImpl::TEST_GetLevel0TotalSize() {
  return default_cf_handle_->cfd()->current()->storage_info()->NumLevelBytes(0);
 }

-Iterator* DBImpl::TEST_NewInternalIterator(Arena* arena,
-                                           ColumnFamilyHandle* column_family) {
-  ColumnFamilyData* cfd;
-  if (column_family == nullptr) {
-    cfd = default_cf_handle_->cfd();
-  } else {
-    auto cfh = reinterpret_cast<ColumnFamilyHandleImpl*>(column_family);
-    cfd = cfh->cfd();
-  }
-
-  mutex_.Lock();
-  SuperVersion* super_version = cfd->GetSuperVersion()->Ref();
-  mutex_.Unlock();
-  ReadOptions roptions;
-  return NewInternalIterator(roptions, cfd, super_version, arena);
-}
-
 int64_t DBImpl::TEST_MaxNextLevelOverlappingBytes(
    ColumnFamilyHandle* column_family) {
  ColumnFamilyData* cfd;
@@ -87,7 +70,7 @@ Status DBImpl::TEST_CompactRange(int level, const Slice* begin,
       cfd->ioptions()->compaction_style == kCompactionStyleFIFO)
          ? level
          : level + 1;
-  return RunManualCompaction(cfd, level, output_level, 0, begin, end,
+  return RunManualCompaction(cfd, level, output_level, 0, begin, end, true,
                             disallow_trivial_move);
 }

@@ -152,5 +135,24 @@ uint64_t DBImpl::TEST_LogfileNumber() {
  return logfile_number_;
 }

+Status DBImpl::TEST_GetAllImmutableCFOptions(
+    std::unordered_map<std::string, const ImmutableCFOptions*>* iopts_map) {
+  std::vector<std::string> cf_names;
+  std::vector<const ImmutableCFOptions*> iopts;
+  {
+    InstrumentedMutexLock l(&mutex_);
+    for (auto cfd : *versions_->GetColumnFamilySet()) {
+      cf_names.push_back(cfd->GetName());
+      iopts.push_back(cfd->ioptions());
+    }
+  }
+  iopts_map->clear();
+  for (size_t i = 0; i < cf_names.size(); ++i) {
+    iopts_map->insert({cf_names[i], iopts[i]});
+  }
+
+  return Status::OK();
+}
+
 }  // namespace rocksdb
-#endif  // ROCKSDB_LITE
+#endif  // NDEBUG
@@ -6,8 +6,8 @@
 // Copyright (c) 2011 The LevelDB Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file. See the AUTHORS file for names of contributors.
+#include "db/db_test_util.h"
 #include "port/stack_trace.h"
-#include "util/db_test_util.h"

 namespace rocksdb {

@@ -15,11 +15,12 @@

 #include "db/filename.h"
 #include "db/dbformat.h"
+#include "port/port.h"
 #include "rocksdb/env.h"
 #include "rocksdb/options.h"
 #include "rocksdb/iterator.h"
 #include "rocksdb/merge_operator.h"
-#include "port/port.h"
+#include "table/internal_iterator.h"
 #include "util/arena.h"
 #include "util/logging.h"
 #include "util/mutexlock.h"
@@ -58,10 +59,11 @@ class DBIter: public Iterator {
    kReverse
  };

-  DBIter(Env* env, const ImmutableCFOptions& ioptions,
-         const Comparator* cmp, Iterator* iter, SequenceNumber s,
-         bool arena_mode, uint64_t max_sequential_skip_in_iterations,
-         const Slice* iterate_upper_bound = nullptr)
+  DBIter(Env* env, const ImmutableCFOptions& ioptions, const Comparator* cmp,
+         InternalIterator* iter, SequenceNumber s, bool arena_mode,
+         uint64_t max_sequential_skip_in_iterations,
+         const Slice* iterate_upper_bound = nullptr,
+         bool prefix_same_as_start = false)
      : arena_mode_(arena_mode),
        env_(env),
        logger_(ioptions.info_log),
@@ -73,7 +75,9 @@ class DBIter: public Iterator {
        valid_(false),
        current_entry_is_merged_(false),
        statistics_(ioptions.statistics),
-        iterate_upper_bound_(iterate_upper_bound) {
+        iterate_upper_bound_(iterate_upper_bound),
+        prefix_same_as_start_(prefix_same_as_start),
+        iter_pinned_(false) {
    RecordTick(statistics_, NO_ITERATORS);
    prefix_extractor_ = ioptions.prefix_extractor;
    max_skip_ = max_sequential_skip_in_iterations;
@@ -83,12 +87,15 @@ class DBIter: public Iterator {
    if (!arena_mode_) {
      delete iter_;
    } else {
-      iter_->~Iterator();
+      iter_->~InternalIterator();
    }
  }
-  virtual void SetIter(Iterator* iter) {
+  virtual void SetIter(InternalIterator* iter) {
    assert(iter_ == nullptr);
    iter_ = iter;
+    if (iter_ && iter_pinned_) {
+      iter_->PinData();
+    }
  }
  virtual bool Valid() const override { return valid_; }
  virtual Slice key() const override {
@@ -107,6 +114,32 @@ class DBIter: public Iterator {
      return status_;
    }
  }
+  virtual Status PinData() {
+    Status s;
+    if (iter_) {
+      s = iter_->PinData();
+    }
+    if (s.ok()) {
+      // Even if iter_ is nullptr, we set iter_pinned_ to true so that when
+      // iter_ is updated using SetIter, we Pin it.
+      iter_pinned_ = true;
+    }
+    return s;
+  }
+  virtual Status ReleasePinnedData() {
+    Status s;
+    if (iter_) {
+      s = iter_->ReleasePinnedData();
+    }
+    if (s.ok()) {
+      iter_pinned_ = false;
+    }
+    return s;
+  }
+  virtual bool IsKeyPinned() const override {
+    assert(valid_);
+    return iter_pinned_ && saved_key_.IsKeyPinned();
+  }

  virtual void Next() override;
  virtual void Prev() override;
@@ -142,7 +175,7 @@ class DBIter: public Iterator {
  Logger* logger_;
  const Comparator* const user_comparator_;
  const MergeOperator* const user_merge_operator_;
-  Iterator* iter_;
+  InternalIterator* iter_;
  SequenceNumber const sequence_;

  Status status_;
@@ -154,6 +187,11 @@ class DBIter: public Iterator {
  Statistics* statistics_;
  uint64_t max_skip_;
  const Slice* iterate_upper_bound_;
+  IterKey prefix_start_;
+  bool prefix_same_as_start_;
+  bool iter_pinned_;
+  // List of operands for merge operator.
+  std::deque<std::string> merge_operands_;

  // No copying allowed
  DBIter(const DBIter&);
@@ -181,9 +219,18 @@ void DBIter::Next() {
    if (!iter_->Valid()) {
      iter_->SeekToFirst();
    }
+  } else if (iter_->Valid() && !current_entry_is_merged_) {
+    // If the current value is not a merge, the iter position is the
+    // current key, which is already returned. We can safely issue a
+    // Next() without checking the current key.
+    // If the current key is a merge, very likely iter already points
+    // to the next internal position.
+    iter_->Next();
+    PERF_COUNTER_ADD(internal_key_skipped_count, 1);
  }

-  // If the current value is merged, we might already hit end of iter_
+  // Now we point to the next internal position, for both of merge and
+  // not merge cases.
  if (!iter_->Valid()) {
    valid_ = false;
    return;
@@ -196,6 +243,11 @@ void DBIter::Next() {
      RecordTick(statistics_, ITER_BYTES_READ, key().size() + value().size());
    }
  }
+  if (valid_ && prefix_extractor_ && prefix_same_as_start_ &&
+      prefix_extractor_->Transform(saved_key_.GetKey())
+              .compare(prefix_start_.GetKey()) != 0) {
+    valid_ = false;
+  }
 }

 // PRE: saved_key_ has the current user key if skipping
@@ -238,18 +290,21 @@ void DBIter::FindNextUserEntryInternal(bool skipping) {
            case kTypeSingleDeletion:
              // Arrange to skip all upcoming entries for this key since
              // they are hidden by this deletion.
-              saved_key_.SetKey(ikey.user_key);
+              saved_key_.SetKey(ikey.user_key,
+                                !iter_->IsKeyPinned() /* copy */);
              skipping = true;
              num_skipped = 0;
              PERF_COUNTER_ADD(internal_delete_skipped_count, 1);
              break;
            case kTypeValue:
              valid_ = true;
-              saved_key_.SetKey(ikey.user_key);
+              saved_key_.SetKey(ikey.user_key,
+                                !iter_->IsKeyPinned() /* copy */);
              return;
            case kTypeMerge:
              // By now, we are sure the current ikey is going to yield a value
-              saved_key_.SetKey(ikey.user_key);
+              saved_key_.SetKey(ikey.user_key,
+                                !iter_->IsKeyPinned() /* copy */);
              current_entry_is_merged_ = true;
              valid_ = true;
              MergeValuesNewToOld();  // Go to a different state machine
@@ -366,6 +421,11 @@ void DBIter::Prev() {
      RecordTick(statistics_, ITER_BYTES_READ, key().size() + value().size());
    }
  }
+  if (valid_ && prefix_extractor_ && prefix_same_as_start_ &&
+      prefix_extractor_->Transform(saved_key_.GetKey())
+              .compare(prefix_start_.GetKey()) != 0) {
+    valid_ = false;
+  }
 }

 void DBIter::ReverseToBackward() {
@@ -404,7 +464,8 @@ void DBIter::PrevInternal() {
  ParsedInternalKey ikey;

  while (iter_->Valid()) {
-    saved_key_.SetKey(ExtractUserKey(iter_->key()));
+    saved_key_.SetKey(ExtractUserKey(iter_->key()),
+                      !iter_->IsKeyPinned() /* copy */);
    if (FindValueForCurrentKey()) {
      valid_ = true;
      if (!iter_->Valid()) {
@@ -434,8 +495,7 @@ void DBIter::PrevInternal() {
 // saved_value_
 bool DBIter::FindValueForCurrentKey() {
  assert(iter_->Valid());
-  // Contains operands for merge operator.
-  std::deque<std::string> operands;
+  merge_operands_.clear();
  // last entry before merge (could be kTypeDeletion, kTypeSingleDeletion or
  // kTypeValue)
  ValueType last_not_merge_type = kTypeDeletion;
@@ -455,19 +515,19 @@ bool DBIter::FindValueForCurrentKey() {
    last_key_entry_type = ikey.type;
    switch (last_key_entry_type) {
      case kTypeValue:
-        operands.clear();
+        merge_operands_.clear();
        saved_value_ = iter_->value().ToString();
        last_not_merge_type = kTypeValue;
        break;
      case kTypeDeletion:
      case kTypeSingleDeletion:
-        operands.clear();
+        merge_operands_.clear();
        last_not_merge_type = last_key_entry_type;
        PERF_COUNTER_ADD(internal_delete_skipped_count, 1);
        break;
      case kTypeMerge:
        assert(user_merge_operator_ != nullptr);
-        operands.push_back(iter_->value().ToString());
+        merge_operands_.push_back(iter_->value().ToString());
        break;
      default:
        assert(false);
@@ -489,8 +549,9 @@ bool DBIter::FindValueForCurrentKey() {
      if (last_not_merge_type == kTypeDeletion) {
        StopWatchNano timer(env_, statistics_ != nullptr);
        PERF_TIMER_GUARD(merge_operator_time_nanos);
-        user_merge_operator_->FullMerge(saved_key_.GetKey(), nullptr, operands,
-                                        &saved_value_, logger_);
+        user_merge_operator_->FullMerge(saved_key_.GetKey(), nullptr,
+                                        merge_operands_, &saved_value_,
+                                        logger_);
        RecordTick(statistics_, MERGE_OPERATION_TOTAL_TIME,
                   timer.ElapsedNanos());
      } else {
@@ -501,7 +562,8 @@ bool DBIter::FindValueForCurrentKey() {
          StopWatchNano timer(env_, statistics_ != nullptr);
          PERF_TIMER_GUARD(merge_operator_time_nanos);
          user_merge_operator_->FullMerge(saved_key_.GetKey(), &temp_slice,
-                                          operands, &saved_value_, logger_);
+                                          merge_operands_, &saved_value_,
+                                          logger_);
          RecordTick(statistics_, MERGE_OPERATION_TOTAL_TIME,
                     timer.ElapsedNanos());
        }
@@ -667,6 +729,9 @@ void DBIter::Seek(const Slice& target) {
  } else {
    valid_ = false;
  }
+  if (valid_ && prefix_extractor_ && prefix_same_as_start_) {
+    prefix_start_.SetKey(prefix_extractor_->Transform(target));
+  }
 }

 void DBIter::SeekToFirst() {
@@ -695,6 +760,9 @@ void DBIter::SeekToFirst() {
  } else {
    valid_ = false;
  }
+  if (valid_ && prefix_extractor_ && prefix_same_as_start_) {
+    prefix_start_.SetKey(prefix_extractor_->Transform(saved_key_.GetKey()));
+  }
 }

 void DBIter::SeekToLast() {
@@ -714,7 +782,7 @@ void DBIter::SeekToLast() {
  // it will seek to the last key before the
  // ReadOptions.iterate_upper_bound
  if (iter_->Valid() && iterate_upper_bound_ != nullptr) {
-    saved_key_.SetKey(*iterate_upper_bound_);
+    saved_key_.SetKey(*iterate_upper_bound_, false /* copy */);
    std::string last_key;
    AppendInternalKey(&last_key,
                      ParsedInternalKey(saved_key_.GetKey(), kMaxSequenceNumber,
@@ -740,24 +808,33 @@ void DBIter::SeekToLast() {
      RecordTick(statistics_, ITER_BYTES_READ, key().size() + value().size());
    }
  }
+  if (valid_ && prefix_extractor_ && prefix_same_as_start_) {
+    prefix_start_.SetKey(prefix_extractor_->Transform(saved_key_.GetKey()));
+  }
 }

 Iterator* NewDBIterator(Env* env, const ImmutableCFOptions& ioptions,
                        const Comparator* user_key_comparator,
-                        Iterator* internal_iter,
+                        InternalIterator* internal_iter,
                        const SequenceNumber& sequence,
                        uint64_t max_sequential_skip_in_iterations,
-                        const Slice* iterate_upper_bound) {
-  return new DBIter(env, ioptions, user_key_comparator, internal_iter, sequence,
-                    false, max_sequential_skip_in_iterations,
-                    iterate_upper_bound);
+                        const Slice* iterate_upper_bound,
+                        bool prefix_same_as_start, bool pin_data) {
+  DBIter* db_iter =
+      new DBIter(env, ioptions, user_key_comparator, internal_iter, sequence,
+                 false, max_sequential_skip_in_iterations, iterate_upper_bound,
+                 prefix_same_as_start);
+  if (pin_data) {
+    db_iter->PinData();
+  }
+  return db_iter;
 }

 ArenaWrappedDBIter::~ArenaWrappedDBIter() { db_iter_->~DBIter(); }

 void ArenaWrappedDBIter::SetDBIter(DBIter* iter) { db_iter_ = iter; }

-void ArenaWrappedDBIter::SetIterUnderDBIter(Iterator* iter) {
+void ArenaWrappedDBIter::SetIterUnderDBIter(InternalIterator* iter) {
  static_cast<DBIter*>(db_iter_)->SetIter(iter);
 }

@@ -772,6 +849,13 @@ inline void ArenaWrappedDBIter::Prev() { db_iter_->Prev(); }
 inline Slice ArenaWrappedDBIter::key() const { return db_iter_->key(); }
 inline Slice ArenaWrappedDBIter::value() const { return db_iter_->value(); }
 inline Status ArenaWrappedDBIter::status() const { return db_iter_->status(); }
+inline Status ArenaWrappedDBIter::PinData() { return db_iter_->PinData(); }
+inline Status ArenaWrappedDBIter::ReleasePinnedData() {
+  return db_iter_->ReleasePinnedData();
+}
+inline bool ArenaWrappedDBIter::IsKeyPinned() const {
+  return db_iter_->IsKeyPinned();
+}
 void ArenaWrappedDBIter::RegisterCleanup(CleanupFunction function, void* arg1,
                                         void* arg2) {
  db_iter_->RegisterCleanup(function, arg1, arg2);
@@ -779,18 +863,22 @@ void ArenaWrappedDBIter::RegisterCleanup(CleanupFunction function, void* arg1,

 ArenaWrappedDBIter* NewArenaWrappedDbIterator(
    Env* env, const ImmutableCFOptions& ioptions,
-    const Comparator* user_key_comparator,
-    const SequenceNumber& sequence,
+    const Comparator* user_key_comparator, const SequenceNumber& sequence,
    uint64_t max_sequential_skip_in_iterations,
-    const Slice* iterate_upper_bound) {
+    const Slice* iterate_upper_bound, bool prefix_same_as_start,
+    bool pin_data) {
  ArenaWrappedDBIter* iter = new ArenaWrappedDBIter();
  Arena* arena = iter->GetArena();
  auto mem = arena->AllocateAligned(sizeof(DBIter));
-  DBIter* db_iter = new (mem) DBIter(env, ioptions, user_key_comparator,
-      nullptr, sequence, true, max_sequential_skip_in_iterations,
-      iterate_upper_bound);
+  DBIter* db_iter =
+      new (mem) DBIter(env, ioptions, user_key_comparator, nullptr, sequence,
+                       true, max_sequential_skip_in_iterations,
+                       iterate_upper_bound, prefix_same_as_start);

  iter->SetDBIter(db_iter);
+  if (pin_data) {
+    iter->PinData();
+  }

  return iter;
 }
@@ -10,6 +10,7 @@
 #pragma once
 #include <stdint.h>
 #include "rocksdb/db.h"
+#include "rocksdb/iterator.h"
 #include "db/dbformat.h"
 #include "util/arena.h"
 #include "util/autovector.h"
@@ -18,18 +19,19 @@ namespace rocksdb {

 class Arena;
 class DBIter;
+class InternalIterator;

 // Return a new iterator that converts internal keys (yielded by
 // "*internal_iter") that were live at the specified "sequence" number
 // into appropriate user keys.
-extern Iterator* NewDBIterator(
-    Env* env,
-    const ImmutableCFOptions& options,
-    const Comparator *user_key_comparator,
-    Iterator* internal_iter,
-    const SequenceNumber& sequence,
-    uint64_t max_sequential_skip_in_iterations,
-    const Slice* iterate_upper_bound = nullptr);
+extern Iterator* NewDBIterator(Env* env, const ImmutableCFOptions& options,
+                               const Comparator* user_key_comparator,
+                               InternalIterator* internal_iter,
+                               const SequenceNumber& sequence,
+                               uint64_t max_sequential_skip_in_iterations,
+                               const Slice* iterate_upper_bound = nullptr,
+                               bool prefix_same_as_start = false,
+                               bool pin_data = false);

 // A wrapper iterator which wraps DB Iterator and the arena, with which the DB
 // iterator is supposed be allocated. This class is used as an entry point of
@@ -50,7 +52,7 @@ class ArenaWrappedDBIter : public Iterator {

  // Set the internal iterator wrapped inside the DB Iterator. Usually it is
  // a merging iterator.
-  virtual void SetIterUnderDBIter(Iterator* iter);
+  virtual void SetIterUnderDBIter(InternalIterator* iter);
  virtual bool Valid() const override;
  virtual void SeekToFirst() override;
  virtual void SeekToLast() override;
@@ -60,7 +62,11 @@ class ArenaWrappedDBIter : public Iterator {
  virtual Slice key() const override;
  virtual Slice value() const override;
  virtual Status status() const override;
+
  void RegisterCleanup(CleanupFunction function, void* arg1, void* arg2);
+  virtual Status PinData();
+  virtual Status ReleasePinnedData();
+  virtual bool IsKeyPinned() const override;

 private:
  DBIter* db_iter_;
@@ -70,8 +76,9 @@ class ArenaWrappedDBIter : public Iterator {
 // Generate the arena wrapped iterator class.
 extern ArenaWrappedDBIter* NewArenaWrappedDbIterator(
    Env* env, const ImmutableCFOptions& options,
-    const Comparator* user_key_comparator,
-    const SequenceNumber& sequence, uint64_t max_sequential_skip_in_iterations,
-    const Slice* iterate_upper_bound = nullptr);
+    const Comparator* user_key_comparator, const SequenceNumber& sequence,
+    uint64_t max_sequential_skip_in_iterations,
+    const Slice* iterate_upper_bound = nullptr,
+    bool prefix_same_as_start = false, bool pin_data = false);

 }  // namespace rocksdb
@@ -29,7 +29,7 @@ static uint64_t TestGetTickerCount(const Options& options,
  return options.statistics->getTickerCount(ticker_type);
 }

-class TestIterator : public Iterator {
+class TestIterator : public InternalIterator {
 public:
  explicit TestIterator(const Comparator* comparator)
      : initialized_(false),
@@ -1864,11 +1864,12 @@ class DBIterWithMergeIterTest : public testing::Test {
    internal_iter2_->Add("d", kTypeValue, "7", 3u);
    internal_iter2_->Finish();

-    std::vector<Iterator*> child_iters;
+    std::vector<InternalIterator*> child_iters;
    child_iters.push_back(internal_iter1_);
    child_iters.push_back(internal_iter2_);
    InternalKeyComparator icomp(BytewiseComparator());
-    Iterator* merge_iter = NewMergingIterator(&icomp_, &child_iters[0], 2u);
+    InternalIterator* merge_iter =
+        NewMergingIterator(&icomp_, &child_iters[0], 2u);

    db_iter_.reset(NewDBIterator(env_, ImmutableCFOptions(options_),
                                 BytewiseComparator(), merge_iter,
@@ -1942,8 +1943,6 @@ TEST_F(DBIterWithMergeIterTest, InnerMergeIterator2) {
  ASSERT_EQ(db_iter_->value().ToString(), "4");
 }

-#if !(defined NDEBUG) || !defined(OS_WIN)
-
 TEST_F(DBIterWithMergeIterTest, InnerMergeIteratorDataRace1) {
  // Test Prev() when one child iterator is at its end but more rows
  // are added.
@@ -2294,7 +2293,6 @@ TEST_F(DBIterWithMergeIterTest, InnerMergeIteratorDataRace8) {

  rocksdb::SyncPoint::GetInstance()->DisableProcessing();
 }
-#endif // #if !(defined NDEBUG) || !defined(OS_WIN)
 }  // namespace rocksdb

 int main(int argc, char** argv) {
@@ -10,10 +10,10 @@
 // Introduction of SyncPoint effectively disabled building and running this test
 // in Release build.
 // which is a pity, it is a good test
-#if !(defined NDEBUG) || !defined(OS_WIN)
+#if !defined(ROCKSDB_LITE)

+#include "db/db_test_util.h"
 #include "port/stack_trace.h"
-#include "util/db_test_util.h"

 namespace rocksdb {

@@ -27,7 +27,7 @@ class DBTestXactLogIterator : public DBTestBase {
    Status status = dbfull()->GetUpdatesSince(seq, &iter);
    EXPECT_OK(status);
    EXPECT_TRUE(iter->Valid());
-    return std::move(iter);
+    return iter;
  }
 };

@@ -277,10 +277,10 @@ TEST_F(DBTestXactLogIterator, TransactionLogIteratorBlobs) {
 }
 }  // namespace rocksdb

-#endif  // !(defined NDEBUG) || !defined(OS_WIN)
+#endif  // !defined(ROCKSDB_LITE)

 int main(int argc, char** argv) {
-#if !(defined NDEBUG) || !defined(OS_WIN)
+#if !defined(ROCKSDB_LITE)
  rocksdb::port::InstallStackTraceHandler();
  ::testing::InitGoogleTest(&argc, argv);
  return RUN_ALL_TESTS();
@@ -0,0 +1,226 @@
+//  Copyright (c) 2013, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under the BSD-style license found in the
+//  LICENSE file in the root directory of this source tree. An additional grant
+//  of patent rights can be found in the PATENTS file in the same directory.
+//
+// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file. See the AUTHORS file for names of contributors.
+
+#include <unordered_set>
+#include <vector>
+
+#include "db/db_test_util.h"
+#include "port/stack_trace.h"
+#include "rocksdb/db.h"
+#include "util/testharness.h"
+#include "util/testutil.h"
+
+#ifndef ROCKSDB_LITE
+
+namespace rocksdb {
+
+// A helper function that ensures the table properties returned in
+// `GetPropertiesOfAllTablesTest` is correct.
+// This test assumes entries size is different for each of the tables.
+namespace {
+
+void VerifyTableProperties(DB* db, uint64_t expected_entries_size) {
+  TablePropertiesCollection props;
+  ASSERT_OK(db->GetPropertiesOfAllTables(&props));
+
+  ASSERT_EQ(4U, props.size());
+  std::unordered_set<uint64_t> unique_entries;
+
+  // Indirect test
+  uint64_t sum = 0;
+  for (const auto& item : props) {
+    unique_entries.insert(item.second->num_entries);
+    sum += item.second->num_entries;
+  }
+
+  ASSERT_EQ(props.size(), unique_entries.size());
+  ASSERT_EQ(expected_entries_size, sum);
+}
+}  // namespace
+
+class DBTablePropertiesTest : public DBTestBase {
+ public:
+  DBTablePropertiesTest() : DBTestBase("/db_table_properties_test") {}
+  TablePropertiesCollection TestGetPropertiesOfTablesInRange(
+      std::vector<Range> ranges, std::size_t* num_properties = nullptr,
+      std::size_t* num_files = nullptr);
+};
+
+TEST_F(DBTablePropertiesTest, GetPropertiesOfAllTablesTest) {
+  Options options = CurrentOptions();
+  options.level0_file_num_compaction_trigger = 8;
+  Reopen(options);
+  // Create 4 tables
+  for (int table = 0; table < 4; ++table) {
+    for (int i = 0; i < 10 + table; ++i) {
+      db_->Put(WriteOptions(), ToString(table * 100 + i), "val");
+    }
+    db_->Flush(FlushOptions());
+  }
+
+  // 1. Read table properties directly from file
+  Reopen(options);
+  VerifyTableProperties(db_, 10 + 11 + 12 + 13);
+
+  // 2. Put two tables to table cache and
+  Reopen(options);
+  // fetch key from 1st and 2nd table, which will internally place that table to
+  // the table cache.
+  for (int i = 0; i < 2; ++i) {
+    Get(ToString(i * 100 + 0));
+  }
+
+  VerifyTableProperties(db_, 10 + 11 + 12 + 13);
+
+  // 3. Put all tables to table cache
+  Reopen(options);
+  // fetch key from 1st and 2nd table, which will internally place that table to
+  // the table cache.
+  for (int i = 0; i < 4; ++i) {
+    Get(ToString(i * 100 + 0));
+  }
+  VerifyTableProperties(db_, 10 + 11 + 12 + 13);
+}
+
+TablePropertiesCollection
+DBTablePropertiesTest::TestGetPropertiesOfTablesInRange(
+    std::vector<Range> ranges, std::size_t* num_properties,
+    std::size_t* num_files) {
+
+  // Since we deref zero element in the vector it can not be empty
+  // otherwise we pass an address to some random memory
+  EXPECT_GT(ranges.size(), 0U);
+  // run the query
+  TablePropertiesCollection props;
+  EXPECT_OK(db_->GetPropertiesOfTablesInRange(
+      db_->DefaultColumnFamily(), &ranges[0], ranges.size(), &props));
+
+  // Make sure that we've received properties for those and for those files
+  // only which fall within requested ranges
+  std::vector<LiveFileMetaData> vmd;
+  db_->GetLiveFilesMetaData(&vmd);
+  for (auto& md : vmd) {
+    std::string fn = md.db_path + md.name;
+    bool in_range = false;
+    for (auto& r : ranges) {
+      // smallestkey < limit && largestkey >= start
+      if (r.limit.compare(md.smallestkey) >= 0 &&
+          r.start.compare(md.largestkey) <= 0) {
+        in_range = true;
+        EXPECT_GT(props.count(fn), 0);
+      }
+    }
+    if (!in_range) {
+      EXPECT_EQ(props.count(fn), 0);
+    }
+  }
+
+  if (num_properties) {
+    *num_properties = props.size();
+  }
+
+  if (num_files) {
+    *num_files = vmd.size();
+  }
+  return props;
+}
+
+TEST_F(DBTablePropertiesTest, GetPropertiesOfTablesInRange) {
+  // Fixed random sead
+  Random rnd(301);
+
+  Options options;
+  options.create_if_missing = true;
+  options.write_buffer_size = 4096;
+  options.max_write_buffer_number = 8;
+  options.level0_file_num_compaction_trigger = 2;
+  options.level0_slowdown_writes_trigger = 2;
+  options.level0_stop_writes_trigger = 4;
+  options.target_file_size_base = 2048;
+  options.max_bytes_for_level_base = 10240;
+  options.max_bytes_for_level_multiplier = 4;
+  options.soft_rate_limit = 1.1;
+  options.num_levels = 8;
+
+  DestroyAndReopen(options);
+
+  // build a decent LSM
+  for (int i = 0; i < 10000; i++) {
+    ASSERT_OK(Put(test::RandomKey(&rnd, 5), RandomString(&rnd, 102)));
+  }
+  Flush();
+  db_->PauseBackgroundWork();
+
+  // Ensure that we have at least L0, L1 and L2
+  ASSERT_GT(NumTableFilesAtLevel(0), 0);
+  ASSERT_GT(NumTableFilesAtLevel(1), 0);
+  ASSERT_GT(NumTableFilesAtLevel(2), 0);
+
+  // Query the largest range
+  std::size_t num_properties, num_files;
+  TestGetPropertiesOfTablesInRange(
+      {Range(test::RandomKey(&rnd, 5, test::RandomKeyType::SMALLEST),
+             test::RandomKey(&rnd, 5, test::RandomKeyType::LARGEST))},
+      &num_properties, &num_files);
+  ASSERT_EQ(num_properties, num_files);
+
+  // Query the empty range
+  TestGetPropertiesOfTablesInRange(
+      {Range(test::RandomKey(&rnd, 5, test::RandomKeyType::LARGEST),
+             test::RandomKey(&rnd, 5, test::RandomKeyType::SMALLEST))},
+      &num_properties, &num_files);
+  ASSERT_GT(num_files, 0);
+  ASSERT_EQ(num_properties, 0);
+
+  // Query the middle rangee
+  TestGetPropertiesOfTablesInRange(
+      {Range(test::RandomKey(&rnd, 5, test::RandomKeyType::MIDDLE),
+             test::RandomKey(&rnd, 5, test::RandomKeyType::LARGEST))},
+      &num_properties, &num_files);
+  ASSERT_GT(num_files, 0);
+  ASSERT_GT(num_files, num_properties);
+  ASSERT_GT(num_properties, 0);
+
+  // Query a bunch of random ranges
+  for (int j = 0; j < 100; j++) {
+    // create a bunch of ranges
+    std::vector<std::string> random_keys;
+    // Random returns numbers with zero included
+    // when we pass empty ranges TestGetPropertiesOfTablesInRange()
+    // derefs random memory in the empty ranges[0]
+    // so want to be greater than zero and even since
+    // the below loop requires that random_keys.size() to be even.
+    auto n = 2 * (rnd.Uniform(50) + 1);
+
+    for (uint32_t i = 0; i < n; ++i) {
+      random_keys.push_back(test::RandomKey(&rnd, 5));
+    }
+
+    ASSERT_GT(random_keys.size(), 0U);
+    ASSERT_EQ((random_keys.size() % 2), 0U);
+
+    std::vector<Range> ranges;
+    auto it = random_keys.begin();
+    while (it != random_keys.end()) {
+      ranges.push_back(Range(*it, *(it + 1)));
+      it += 2;
+    }
+
+    TestGetPropertiesOfTablesInRange(std::move(ranges));
+  }
+}
+}  // namespace rocksdb
+
+#endif  // ROCKSDB_LITE
+
+int main(int argc, char** argv) {
+  rocksdb::port::InstallStackTraceHandler();
+  ::testing::InitGoogleTest(&argc, argv);
+  return RUN_ALL_TESTS();
+}
@@ -10,11 +10,11 @@
 // Introduction of SyncPoint effectively disabled building and running this test
 // in Release build.
 // which is a pity, it is a good test
-#if !(defined NDEBUG) || !defined(OS_WIN)
+#if !defined(ROCKSDB_LITE)

+#include "db/db_test_util.h"
 #include "db/forward_iterator.h"
 #include "port/stack_trace.h"
-#include "util/db_test_util.h"

 namespace rocksdb {

@@ -140,6 +140,8 @@ TEST_F(DBTestTailingIterator, TailingIteratorTrimSeekToNext) {
  std::unique_ptr<Iterator> iterh(db_->NewIterator(read_options, handles_[1]));
  std::string value(1024, 'a');
  bool file_iters_deleted = false;
+  bool file_iters_renewed_null = false;
+  bool file_iters_renewed_copy = false;
  rocksdb::SyncPoint::GetInstance()->SetCallBack(
      "ForwardIterator::SeekInternal:Return", [&](void* arg) {
        ForwardIterator* fiter = reinterpret_cast<ForwardIterator*>(arg);
@@ -152,6 +154,12 @@ TEST_F(DBTestTailingIterator, TailingIteratorTrimSeekToNext) {
        ASSERT_TRUE(!file_iters_deleted ||
                    fiter->TEST_CheckDeletedIters(&deleted_iters, &num_iters));
      });
+  rocksdb::SyncPoint::GetInstance()->SetCallBack(
+      "ForwardIterator::RenewIterators:Null",
+      [&](void* arg) { file_iters_renewed_null = true; });
+  rocksdb::SyncPoint::GetInstance()->SetCallBack(
+      "ForwardIterator::RenewIterators:Copy",
+      [&](void* arg) { file_iters_renewed_copy = true; });
  rocksdb::SyncPoint::GetInstance()->EnableProcessing();
  const int num_records = 1000;
  for (int i = 1; i < num_records; ++i) {
@@ -160,7 +168,7 @@ TEST_F(DBTestTailingIterator, TailingIteratorTrimSeekToNext) {
    char buf3[32];
    char buf4[32];
    snprintf(buf1, sizeof(buf1), "00a0%016d", i * 5);
-    snprintf(buf3, sizeof(buf1), "00b0%016d", i * 5);
+    snprintf(buf3, sizeof(buf3), "00b0%016d", i * 5);

    Slice key(buf1, 20);
    ASSERT_OK(Put(1, key, value));
@@ -173,7 +181,7 @@ TEST_F(DBTestTailingIterator, TailingIteratorTrimSeekToNext) {
      if (i == 299) {
        file_iters_deleted = true;
      }
-      snprintf(buf4, sizeof(buf1), "00a0%016d", i * 5 / 2);
+      snprintf(buf4, sizeof(buf4), "00a0%016d", i * 5 / 2);
      Slice target(buf4, 20);
      iterh->Seek(target);
      ASSERT_TRUE(iter->Valid());
@@ -203,6 +211,8 @@ TEST_F(DBTestTailingIterator, TailingIteratorTrimSeekToNext) {
    ASSERT_LE(num_iters, 1);
    file_iters_deleted = false;
  }
+  ASSERT_TRUE(file_iters_renewed_null);
+  ASSERT_TRUE(file_iters_renewed_copy);
  iter = 0;
  itern = 0;
  iterh = 0;
@@ -646,10 +656,10 @@ TEST_F(DBTestTailingIterator, ManagedTailingIteratorSeekToSame) {

 }  // namespace rocksdb

-#endif  // !(defined NDEBUG) || !defined(OS_WIN)
+#endif  // !defined(ROCKSDB_LITE)

 int main(int argc, char** argv) {
-#if !(defined NDEBUG) || !defined(OS_WIN)
+#if !defined(ROCKSDB_LITE)
  rocksdb::port::InstallStackTraceHandler();
  ::testing::InitGoogleTest(&argc, argv);
  return RUN_ALL_TESTS();
@@ -7,7 +7,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file. See the AUTHORS file for names of contributors.

-#include "util/db_test_util.h"
+#include "db/db_test_util.h"

 namespace rocksdb {

@@ -18,6 +18,7 @@ SpecialEnv::SpecialEnv(Env* base)
      rnd_(301),
      sleep_counter_(this),
      addon_time_(0),
+      time_elapse_only_sleep_(false),
      no_sleep_(false) {
  delay_sstable_sync_.store(false, std::memory_order_release);
  drop_writes_.store(false, std::memory_order_release);
@@ -38,11 +39,10 @@ SpecialEnv::SpecialEnv(Env* base)
  table_write_callback_ = nullptr;
 }

-
-DBTestBase::DBTestBase(const std::string path) : option_config_(kDefault),
-           mem_env_(!getenv("MEM_ENV") ? nullptr :
-                                         new MockEnv(Env::Default())),
-           env_(new SpecialEnv(mem_env_ ? mem_env_ : Env::Default())) {
+DBTestBase::DBTestBase(const std::string path)
+    : option_config_(kDefault),
+      mem_env_(!getenv("MEM_ENV") ? nullptr : new MockEnv(Env::Default())),
+      env_(new SpecialEnv(mem_env_ ? mem_env_ : Env::Default())) {
  env_->SetBackgroundThreads(1, Env::LOW);
  env_->SetBackgroundThreads(1, Env::HIGH);
  dbname_ = test::TmpDir(env_) + path;
@@ -56,15 +56,13 @@ DBTestBase::DBTestBase(const std::string path) : option_config_(kDefault),
  EXPECT_OK(DestroyDB(dbname_, options));
  db_ = nullptr;
  Reopen(options);
+  Random::GetTLSInstance()->Reset(0xdeadbeef);
 }

 DBTestBase::~DBTestBase() {
-// SyncPoint is not supported in Released Windows Mode.
-#if !(defined NDEBUG) || !defined(OS_WIN)
  rocksdb::SyncPoint::GetInstance()->DisableProcessing();
  rocksdb::SyncPoint::GetInstance()->LoadDependency({});
  rocksdb::SyncPoint::GetInstance()->ClearAllCallBacks();
-#endif  // !(defined NDEBUG) || !defined(OS_WIN)
  Close();
  Options options;
  options.db_paths.emplace_back(dbname_, 0);
@@ -79,6 +77,24 @@ DBTestBase::~DBTestBase() {
 // test.  Return false if there are no more configurations to test.
 bool DBTestBase::ChangeOptions(int skip_mask) {
  for (option_config_++; option_config_ < kEnd; option_config_++) {
+#ifdef ROCKSDB_LITE
+    // These options are not supported in ROCKSDB_LITE
+    if (option_config_ == kHashSkipList ||
+        option_config_ == kPlainTableFirstBytePrefix ||
+        option_config_ == kPlainTableCappedPrefix ||
+        option_config_ == kPlainTableCappedPrefixNonMmap ||
+        option_config_ == kPlainTableAllBytesPrefix ||
+        option_config_ == kVectorRep || option_config_ == kHashLinkList ||
+        option_config_ == kHashCuckoo ||
+        option_config_ == kUniversalCompaction ||
+        option_config_ == kUniversalCompactionMultiLevel ||
+        option_config_ == kUniversalSubcompactions ||
+        option_config_ == kFIFOCompaction ||
+        option_config_ == kConcurrentSkipList) {
+      continue;
+    }
+#endif
+
    if ((skip_mask & kSkipDeletesFilterFirst) &&
        option_config_ == kDeletesFilterFirst) {
      continue;
@@ -92,8 +108,7 @@ bool DBTestBase::ChangeOptions(int skip_mask) {
      continue;
    }
    if ((skip_mask & kSkipNoSeekToLast) &&
-        (option_config_ == kHashLinkList ||
-         option_config_ == kHashSkipList)) {;
+        (option_config_ == kHashLinkList || option_config_ == kHashSkipList)) {
      continue;
    }
    if ((skip_mask & kSkipPlainTable) &&
@@ -115,8 +130,7 @@ bool DBTestBase::ChangeOptions(int skip_mask) {
        option_config_ == kFIFOCompaction) {
      continue;
    }
-    if ((skip_mask & kSkipMmapReads) &&
-        option_config_ == kWalDirAndMmapReads) {
+    if ((skip_mask & kSkipMmapReads) && option_config_ == kWalDirAndMmapReads) {
      continue;
    }
    break;
@@ -205,10 +219,10 @@ Options DBTestBase::CurrentOptions(
  BlockBasedTableOptions table_options;
  bool set_block_based_table_factory = true;
  switch (option_config_) {
+#ifndef ROCKSDB_LITE
    case kHashSkipList:
      options.prefix_extractor.reset(NewFixedPrefixTransform(1));
-      options.memtable_factory.reset(
-          NewHashSkipListRepFactory(16));
+      options.memtable_factory.reset(NewHashSkipListRepFactory(16));
      break;
    case kPlainTableFirstBytePrefix:
      options.table_factory.reset(new PlainTableFactory());
@@ -238,6 +252,19 @@ Options DBTestBase::CurrentOptions(
      options.max_sequential_skip_in_iterations = 999999;
      set_block_based_table_factory = false;
      break;
+    case kVectorRep:
+      options.memtable_factory.reset(new VectorRepFactory(100));
+      break;
+    case kHashLinkList:
+      options.prefix_extractor.reset(NewFixedPrefixTransform(1));
+      options.memtable_factory.reset(
+          NewHashLinkListRepFactory(4, 0, 3, true, 4));
+      break;
+    case kHashCuckoo:
+      options.memtable_factory.reset(
+          NewHashCuckooRepFactory(options.write_buffer_size));
+      break;
+#endif  // ROCKSDB_LITE
    case kMergePut:
      options.merge_operator = MergeOperators::CreatePutOperator();
      break;
@@ -274,18 +301,6 @@ Options DBTestBase::CurrentOptions(
    case kDeletesFilterFirst:
      options.filter_deletes = true;
      break;
-    case kVectorRep:
-      options.memtable_factory.reset(new VectorRepFactory(100));
-      break;
-    case kHashLinkList:
-      options.prefix_extractor.reset(NewFixedPrefixTransform(1));
-      options.memtable_factory.reset(
-          NewHashLinkListRepFactory(4, 0, 3, true, 4));
-      break;
-    case kHashCuckoo:
-      options.memtable_factory.reset(
-          NewHashCuckooRepFactory(options.write_buffer_size));
-      break;
    case kUniversalCompaction:
      options.compaction_style = kCompactionStyleUniversal;
      options.num_levels = 1;
@@ -296,7 +311,7 @@ Options DBTestBase::CurrentOptions(
      break;
    case kCompressedBlockCache:
      options.allow_mmap_writes = true;
-      table_options.block_cache_compressed = NewLRUCache(8*1024*1024);
+      table_options.block_cache_compressed = NewLRUCache(8 * 1024 * 1024);
      break;
    case kInfiniteMaxOpenFiles:
      options.max_open_files = -1;
@@ -328,6 +343,10 @@ Options DBTestBase::CurrentOptions(
      options.row_cache = NewLRUCache(1024 * 1024);
      break;
    }
+    case kRecycleLogFiles: {
+      options.recycle_log_file_num = 2;
+      break;
+    }
    case kLevelSubcompactions: {
      options.max_subcompactions = 4;
      break;
@@ -338,6 +357,11 @@ Options DBTestBase::CurrentOptions(
      options.max_subcompactions = 4;
      break;
    }
+    case kConcurrentSkipList: {
+      options.allow_concurrent_memtable_write = true;
+      options.enable_write_thread_adaptive_yield = true;
+      break;
+    }

    default:
      break;
@@ -351,11 +375,12 @@ Options DBTestBase::CurrentOptions(
  }
  options.env = env_;
  options.create_if_missing = true;
+  options.fail_if_options_file_error = true;
  return options;
 }

 void DBTestBase::CreateColumnFamilies(const std::vector<std::string>& cfs,
-                          const Options& options) {
+                                      const Options& options) {
  ColumnFamilyOptions cf_opts(options);
  size_t cfi = handles_.size();
  handles_.resize(cfi + cfs.size());
@@ -365,7 +390,7 @@ void DBTestBase::CreateColumnFamilies(const std::vector<std::string>& cfs,
 }

 void DBTestBase::CreateAndReopenWithCF(const std::vector<std::string>& cfs,
-                           const Options& options) {
+                                       const Options& options) {
  CreateColumnFamilies(cfs, options);
  std::vector<std::string> cfs_plus_default = cfs;
  cfs_plus_default.insert(cfs_plus_default.begin(), kDefaultColumnFamilyName);
@@ -373,18 +398,17 @@ void DBTestBase::CreateAndReopenWithCF(const std::vector<std::string>& cfs,
 }

 void DBTestBase::ReopenWithColumnFamilies(const std::vector<std::string>& cfs,
-                              const std::vector<Options>& options) {
+                                          const std::vector<Options>& options) {
  ASSERT_OK(TryReopenWithColumnFamilies(cfs, options));
 }

 void DBTestBase::ReopenWithColumnFamilies(const std::vector<std::string>& cfs,
-                              const Options& options) {
+                                          const Options& options) {
  ASSERT_OK(TryReopenWithColumnFamilies(cfs, options));
 }

 Status DBTestBase::TryReopenWithColumnFamilies(
-    const std::vector<std::string>& cfs,
-    const std::vector<Options>& options) {
+    const std::vector<std::string>& cfs, const std::vector<Options>& options) {
  Close();
  EXPECT_EQ(cfs.size(), options.size());
  std::vector<ColumnFamilyDescriptor> column_families;
@@ -396,8 +420,7 @@ Status DBTestBase::TryReopenWithColumnFamilies(
 }

 Status DBTestBase::TryReopenWithColumnFamilies(
-    const std::vector<std::string>& cfs,
-    const Options& options) {
+    const std::vector<std::string>& cfs, const Options& options) {
  Close();
  std::vector<Options> v_opts(cfs.size(), options);
  return TryReopenWithColumnFamilies(cfs, v_opts);
@@ -454,7 +477,7 @@ Status DBTestBase::Put(const Slice& k, const Slice& v, WriteOptions wo) {
 }

 Status DBTestBase::Put(int cf, const Slice& k, const Slice& v,
-           WriteOptions wo) {
+                       WriteOptions wo) {
  if (kMergePut == option_config_) {
    return db_->Merge(wo, handles_[cf], k, v);
  } else {
@@ -493,7 +516,7 @@ std::string DBTestBase::Get(const std::string& k, const Snapshot* snapshot) {
 }

 std::string DBTestBase::Get(int cf, const std::string& k,
-                const Snapshot* snapshot) {
+                            const Snapshot* snapshot) {
  ReadOptions options;
  options.verify_checksums = true;
  options.snapshot = snapshot;
@@ -552,9 +575,9 @@ std::string DBTestBase::AllEntriesFor(const Slice& user_key, int cf) {
  Arena arena;
  ScopedArenaIterator iter;
  if (cf == 0) {
-    iter.set(dbfull()->TEST_NewInternalIterator(&arena));
+    iter.set(dbfull()->NewInternalIterator(&arena));
  } else {
-    iter.set(dbfull()->TEST_NewInternalIterator(&arena, handles_[cf]));
+    iter.set(dbfull()->NewInternalIterator(&arena, handles_[cf]));
  }
  InternalKey target(user_key, kMaxSequenceNumber, kTypeValue);
  iter->Seek(target.Encode());
@@ -605,6 +628,7 @@ std::string DBTestBase::AllEntriesFor(const Slice& user_key, int cf) {
  return result;
 }

+#ifndef ROCKSDB_LITE
 int DBTestBase::NumSortedRuns(int cf) {
  ColumnFamilyMetaData cf_meta;
  if (cf == 0) {
@@ -631,20 +655,6 @@ uint64_t DBTestBase::TotalSize(int cf) {
  return cf_meta.size;
 }

-int DBTestBase::NumTableFilesAtLevel(int level, int cf) {
-  std::string property;
-  if (cf == 0) {
-    // default cfd
-    EXPECT_TRUE(db_->GetProperty(
-        "rocksdb.num-files-at-level" + NumberToString(level), &property));
-  } else {
-    EXPECT_TRUE(db_->GetProperty(
-        handles_[cf], "rocksdb.num-files-at-level" + NumberToString(level),
-        &property));
-  }
-  return atoi(property.c_str());
-}
-
 uint64_t DBTestBase::SizeAtLevel(int level) {
  std::vector<LiveFileMetaData> metadata;
  db_->GetLiveFilesMetaData(&metadata);
@@ -657,20 +667,41 @@ uint64_t DBTestBase::SizeAtLevel(int level) {
  return sum;
 }

-int DBTestBase::TotalLiveFiles(int cf) {
+size_t DBTestBase::TotalLiveFiles(int cf) {
  ColumnFamilyMetaData cf_meta;
  if (cf == 0) {
    db_->GetColumnFamilyMetaData(&cf_meta);
  } else {
    db_->GetColumnFamilyMetaData(handles_[cf], &cf_meta);
  }
-  int num_files = 0;
+  size_t num_files = 0;
  for (auto& level : cf_meta.levels) {
    num_files += level.files.size();
  }
  return num_files;
 }

+size_t DBTestBase::CountLiveFiles() {
+  std::vector<LiveFileMetaData> metadata;
+  db_->GetLiveFilesMetaData(&metadata);
+  return metadata.size();
+}
+#endif  // ROCKSDB_LITE
+
+int DBTestBase::NumTableFilesAtLevel(int level, int cf) {
+  std::string property;
+  if (cf == 0) {
+    // default cfd
+    EXPECT_TRUE(db_->GetProperty(
+        "rocksdb.num-files-at-level" + NumberToString(level), &property));
+  } else {
+    EXPECT_TRUE(db_->GetProperty(
+        handles_[cf], "rocksdb.num-files-at-level" + NumberToString(level),
+        &property));
+  }
+  return atoi(property.c_str());
+}
+
 int DBTestBase::TotalTableFiles(int cf, int levels) {
  if (levels == -1) {
    levels = CurrentOptions().num_levels;
@@ -713,12 +744,6 @@ size_t DBTestBase::CountFiles() {
  return files.size() + logfiles.size();
 }

-size_t DBTestBase::CountLiveFiles() {
-  std::vector<LiveFileMetaData> metadata;
-  db_->GetLiveFilesMetaData(&metadata);
-  return metadata.size();
-}
-
 uint64_t DBTestBase::Size(const Slice& start, const Slice& limit, int cf) {
  Range r(start, limit);
  uint64_t size;
@@ -731,7 +756,7 @@ uint64_t DBTestBase::Size(const Slice& start, const Slice& limit, int cf) {
 }

 void DBTestBase::Compact(int cf, const Slice& start, const Slice& limit,
-             uint32_t target_path_id) {
+                         uint32_t target_path_id) {
  CompactRangeOptions compact_options;
  compact_options.target_path_id = target_path_id;
  ASSERT_OK(db_->CompactRange(compact_options, handles_[cf], &start, &limit));
@@ -748,9 +773,8 @@ void DBTestBase::Compact(const Slice& start, const Slice& limit) {

 // Do n memtable compactions, each of which produces an sstable
 // covering the range [small,large].
-void DBTestBase::MakeTables(
-    int n, const std::string& small,
-    const std::string& large, int cf) {
+void DBTestBase::MakeTables(int n, const std::string& small,
+                            const std::string& large, int cf) {
  for (int i = 0; i < n; i++) {
    ASSERT_OK(Put(cf, small, "begin"));
    ASSERT_OK(Put(cf, large, "end"));
@@ -761,8 +785,8 @@ void DBTestBase::MakeTables(

 // Prevent pushing of new sstables into deeper levels by adding
 // tables that cover a specified range to all levels.
-void DBTestBase::FillLevels(
-    const std::string& smallest, const std::string& largest, int cf) {
+void DBTestBase::FillLevels(const std::string& smallest,
+                            const std::string& largest, int cf) {
  MakeTables(db_->NumberLevels(handles_[cf]), smallest, largest, cf);
 }

@@ -779,7 +803,7 @@ void DBTestBase::MoveFilesToLevel(int level, int cf) {
 void DBTestBase::DumpFileCounts(const char* label) {
  fprintf(stderr, "---\n%s:\n", label);
  fprintf(stderr, "maxoverlap: %" PRIu64 "\n",
-      dbfull()->TEST_MaxNextLevelOverlappingBytes());
+          dbfull()->TEST_MaxNextLevelOverlappingBytes());
  for (int level = 0; level < db_->NumberLevels(); level++) {
    int num = NumTableFilesAtLevel(level);
    if (num > 0) {
@@ -815,7 +839,7 @@ int DBTestBase::GetSstFileCount(std::string path) {
 // this will generate non-overlapping files since it keeps increasing key_idx
 void DBTestBase::GenerateNewFile(int cf, Random* rnd, int* key_idx,
                                 bool nowait) {
-  for (int i = 0; i < 100; i++) {
+  for (int i = 0; i < KNumKeysByGenerateNewFile; i++) {
    ASSERT_OK(Put(cf, Key(*key_idx), RandomString(rnd, (i == 99) ? 1 : 990)));
    (*key_idx)++;
  }
@@ -827,7 +851,7 @@ void DBTestBase::GenerateNewFile(int cf, Random* rnd, int* key_idx,

 // this will generate non-overlapping files since it keeps increasing key_idx
 void DBTestBase::GenerateNewFile(Random* rnd, int* key_idx, bool nowait) {
-  for (int i = 0; i < 100; i++) {
+  for (int i = 0; i < KNumKeysByGenerateNewFile; i++) {
    ASSERT_OK(Put(Key(*key_idx), RandomString(rnd, (i == 99) ? 1 : 990)));
    (*key_idx)++;
  }
@@ -837,8 +861,10 @@ void DBTestBase::GenerateNewFile(Random* rnd, int* key_idx, bool nowait) {
  }
 }

+const int DBTestBase::kNumKeysByGenerateNewRandomFile = 51;
+
 void DBTestBase::GenerateNewRandomFile(Random* rnd, bool nowait) {
-  for (int i = 0; i < 51; i++) {
+  for (int i = 0; i < kNumKeysByGenerateNewRandomFile; i++) {
    ASSERT_OK(Put("key" + RandomString(rnd, 7), RandomString(rnd, 2000)));
  }
  ASSERT_OK(Put("key" + RandomString(rnd, 7), RandomString(rnd, 200)));
@@ -888,9 +914,10 @@ void DBTestBase::VerifyIterLast(std::string expected_key, int cf) {
 //   sets newValue with delta
 // If previous value is not empty,
 //   updates previous value with 'b' string of previous value size - 1.
-UpdateStatus DBTestBase::updateInPlaceSmallerSize(
-    char* prevValue, uint32_t* prevSize,
-    Slice delta, std::string* newValue) {
+UpdateStatus DBTestBase::updateInPlaceSmallerSize(char* prevValue,
+                                                  uint32_t* prevSize,
+                                                  Slice delta,
+                                                  std::string* newValue) {
  if (prevValue == nullptr) {
    *newValue = std::string(delta.size(), 'c');
    return UpdateStatus::UPDATED;
@@ -902,9 +929,10 @@ UpdateStatus DBTestBase::updateInPlaceSmallerSize(
  }
 }

-UpdateStatus DBTestBase::updateInPlaceSmallerVarintSize(
-    char* prevValue, uint32_t* prevSize,
-    Slice delta, std::string* newValue) {
+UpdateStatus DBTestBase::updateInPlaceSmallerVarintSize(char* prevValue,
+                                                        uint32_t* prevSize,
+                                                        Slice delta,
+                                                        std::string* newValue) {
  if (prevValue == nullptr) {
    *newValue = std::string(delta.size(), 'c');
    return UpdateStatus::UPDATED;
@@ -916,16 +944,17 @@ UpdateStatus DBTestBase::updateInPlaceSmallerVarintSize(
  }
 }

-UpdateStatus DBTestBase::updateInPlaceLargerSize(
-    char* prevValue, uint32_t* prevSize,
-    Slice delta, std::string* newValue) {
+UpdateStatus DBTestBase::updateInPlaceLargerSize(char* prevValue,
+                                                 uint32_t* prevSize,
+                                                 Slice delta,
+                                                 std::string* newValue) {
  *newValue = std::string(delta.size(), 'c');
  return UpdateStatus::UPDATED;
 }

-UpdateStatus DBTestBase::updateInPlaceNoAction(
-    char* prevValue, uint32_t* prevSize,
-    Slice delta, std::string* newValue) {
+UpdateStatus DBTestBase::updateInPlaceNoAction(char* prevValue,
+                                               uint32_t* prevSize, Slice delta,
+                                               std::string* newValue) {
  return UpdateStatus::UPDATE_FAILED;
 }

@@ -934,9 +963,9 @@ void DBTestBase::validateNumberOfEntries(int numValues, int cf) {
  ScopedArenaIterator iter;
  Arena arena;
  if (cf != 0) {
-    iter.set(dbfull()->TEST_NewInternalIterator(&arena, handles_[cf]));
+    iter.set(dbfull()->NewInternalIterator(&arena, handles_[cf]));
  } else {
-    iter.set(dbfull()->TEST_NewInternalIterator(&arena));
+    iter.set(dbfull()->NewInternalIterator(&arena));
  }
  iter->SeekToFirst();
  ASSERT_EQ(iter->status().ok(), true);
@@ -953,9 +982,8 @@ void DBTestBase::validateNumberOfEntries(int numValues, int cf) {
  ASSERT_EQ(0, seq);
 }

-void DBTestBase::CopyFile(
-    const std::string& source, const std::string& destination,
-    uint64_t size) {
+void DBTestBase::CopyFile(const std::string& source,
+                          const std::string& destination, uint64_t size) {
  const EnvOptions soptions;
  unique_ptr<SequentialFile> srcfile;
  ASSERT_OK(env_->NewSequentialFile(source, &srcfile, soptions));
@@ -27,8 +27,10 @@
 #include <vector>

 #include "db/db_impl.h"
+#include "db/db_test_util.h"
 #include "db/dbformat.h"
 #include "db/filename.h"
+#include "memtable/hash_linklist_rep.h"
 #include "rocksdb/cache.h"
 #include "rocksdb/compaction_filter.h"
 #include "rocksdb/convenience.h"
@@ -42,12 +44,11 @@
 #include "table/block_based_table_factory.h"
 #include "table/mock_table.h"
 #include "table/plain_table_factory.h"
+#include "table/scoped_arena_iterator.h"
 #include "util/compression.h"
-#include "util/db_test_util.h"
-#include "util/hash_linklist_rep.h"
 #include "util/mock_env.h"
 #include "util/mutexlock.h"
-#include "util/scoped_arena_iterator.h"
+
 #include "util/string_util.h"
 // SyncPoint is not supported in Released Windows Mode.
 #if !(defined NDEBUG) || !defined(OS_WIN)
@@ -117,6 +118,84 @@ struct OptionsOverride {

 }  // namespace anon

+// A hacky skip list mem table that triggers flush after number of entries.
+class SpecialMemTableRep : public MemTableRep {
+ public:
+  explicit SpecialMemTableRep(MemTableAllocator* allocator,
+                              MemTableRep* memtable, int num_entries_flush)
+      : MemTableRep(allocator),
+        memtable_(memtable),
+        num_entries_flush_(num_entries_flush),
+        num_entries_(0) {}
+
+  virtual KeyHandle Allocate(const size_t len, char** buf) override {
+    return memtable_->Allocate(len, buf);
+  }
+
+  // Insert key into the list.
+  // REQUIRES: nothing that compares equal to key is currently in the list.
+  virtual void Insert(KeyHandle handle) override {
+    memtable_->Insert(handle);
+    num_entries_++;
+  }
+
+  // Returns true iff an entry that compares equal to key is in the list.
+  virtual bool Contains(const char* key) const override {
+    return memtable_->Contains(key);
+  }
+
+  virtual size_t ApproximateMemoryUsage() override {
+    // Return a high memory usage when number of entries exceeds the threshold
+    // to trigger a flush.
+    return (num_entries_ < num_entries_flush_) ? 0 : 1024 * 1024 * 1024;
+  }
+
+  virtual void Get(const LookupKey& k, void* callback_args,
+                   bool (*callback_func)(void* arg,
+                                         const char* entry)) override {
+    memtable_->Get(k, callback_args, callback_func);
+  }
+
+  uint64_t ApproximateNumEntries(const Slice& start_ikey,
+                                 const Slice& end_ikey) override {
+    return memtable_->ApproximateNumEntries(start_ikey, end_ikey);
+  }
+
+  virtual MemTableRep::Iterator* GetIterator(Arena* arena = nullptr) override {
+    return memtable_->GetIterator(arena);
+  }
+
+  virtual ~SpecialMemTableRep() override {}
+
+ private:
+  unique_ptr<MemTableRep> memtable_;
+  int num_entries_flush_;
+  int num_entries_;
+};
+
+// The factory for the hacky skip list mem table that triggers flush after
+// number of entries exceeds a threshold.
+class SpecialSkipListFactory : public MemTableRepFactory {
+ public:
+  // After number of inserts exceeds `num_entries_flush` in a mem table, trigger
+  // flush.
+  explicit SpecialSkipListFactory(int num_entries_flush)
+      : num_entries_flush_(num_entries_flush) {}
+
+  virtual MemTableRep* CreateMemTableRep(
+      const MemTableRep::KeyComparator& compare, MemTableAllocator* allocator,
+      const SliceTransform* transform, Logger* logger) override {
+    return new SpecialMemTableRep(
+        allocator, factory_.CreateMemTableRep(compare, allocator, transform, 0),
+        num_entries_flush_);
+  }
+  virtual const char* Name() const override { return "SkipListFactory"; }
+
+ private:
+  SkipListFactory factory_;
+  int num_entries_flush_;
+};
+
 // Special Env used to delay background operations
 class SpecialEnv : public EnvWrapper {
 public:
@@ -131,9 +210,7 @@ class SpecialEnv : public EnvWrapper {

     public:
      SSTableFile(SpecialEnv* env, unique_ptr<WritableFile>&& base)
-          : env_(env),
-            base_(std::move(base)) {
-      }
+          : env_(env), base_(std::move(base)) {}
      Status Append(const Slice& data) override {
        if (env_->table_write_callback_) {
          (*env_->table_write_callback_)();
@@ -148,9 +225,7 @@ class SpecialEnv : public EnvWrapper {
          return base_->Append(data);
        }
      }
-      Status Truncate(uint64_t size) override {
-        return base_->Truncate(size);
-      }
+      Status Truncate(uint64_t size) override { return base_->Truncate(size); }
      Status Close() override {
 // SyncPoint is not supported in Released Windows Mode.
 #if !(defined NDEBUG) || !defined(OS_WIN)
@@ -180,7 +255,7 @@ class SpecialEnv : public EnvWrapper {
    class ManifestFile : public WritableFile {
     public:
      ManifestFile(SpecialEnv* env, unique_ptr<WritableFile>&& b)
-          : env_(env), base_(std::move(b)) { }
+          : env_(env), base_(std::move(b)) {}
      Status Append(const Slice& data) override {
        if (env_->manifest_write_error_.load(std::memory_order_acquire)) {
          return Status::IOError("simulated writer error");
@@ -283,8 +358,7 @@ class SpecialEnv : public EnvWrapper {
     public:
      CountingFile(unique_ptr<RandomAccessFile>&& target,
                   anon::AtomicCounter* counter)
-          : target_(std::move(target)), counter_(counter) {
-      }
+          : target_(std::move(target)), counter_(counter) {}
      virtual Status Read(uint64_t offset, size_t n, Slice* result,
                          char* scratch) const override {
        counter_->Increment();
@@ -329,18 +403,21 @@ class SpecialEnv : public EnvWrapper {
    return s;
  }

-
  virtual void SleepForMicroseconds(int micros) override {
    sleep_counter_.Increment();
-    if (no_sleep_) {
+    if (no_sleep_ || time_elapse_only_sleep_) {
      addon_time_.fetch_add(micros);
-    } else {
+    }
+    if (!no_sleep_) {
      target()->SleepForMicroseconds(micros);
    }
  }

  virtual Status GetCurrentTime(int64_t* unix_time) override {
-    Status s = target()->GetCurrentTime(unix_time);
+    Status s;
+    if (!time_elapse_only_sleep_) {
+      s = target()->GetCurrentTime(unix_time);
+    }
    if (s.ok()) {
      *unix_time += addon_time_.load();
    }
@@ -348,11 +425,13 @@ class SpecialEnv : public EnvWrapper {
  }

  virtual uint64_t NowNanos() override {
-    return target()->NowNanos() + addon_time_.load() * 1000;
+    return (time_elapse_only_sleep_ ? 0 : target()->NowNanos()) +
+           addon_time_.load() * 1000;
  }

  virtual uint64_t NowMicros() override {
-    return target()->NowMicros() + addon_time_.load();
+    return (time_elapse_only_sleep_ ? 0 : target()->NowMicros()) +
+           addon_time_.load();
  }

  Random rnd_;
@@ -404,9 +483,12 @@ class SpecialEnv : public EnvWrapper {
  std::function<void()>* table_write_callback_;

  std::atomic<int64_t> addon_time_;
+
+  bool time_elapse_only_sleep_;
+
  bool no_sleep_;

-  std::atomic<bool> is_wal_sync_thread_safe_ {true};
+  std::atomic<bool> is_wal_sync_thread_safe_{true};
 };

 class DBTestBase : public testing::Test {
@@ -442,9 +524,11 @@ class DBTestBase : public testing::Test {
    kFIFOCompaction = 26,
    kOptimizeFiltersForHits = 27,
    kRowCache = 28,
-    kLevelSubcompactions = 29,
-    kUniversalSubcompactions = 30,
-    kEnd = 29
+    kRecycleLogFiles = 29,
+    kConcurrentSkipList = 30,
+    kEnd = 31,
+    kLevelSubcompactions = 31,
+    kUniversalSubcompactions = 32,
  };
  int option_config_;

@@ -509,9 +593,7 @@ class DBTestBase : public testing::Test {
      const Options& defaultOptions,
      const anon::OptionsOverride& options_override = anon::OptionsOverride());

-  DBImpl* dbfull() {
-    return reinterpret_cast<DBImpl*>(db_);
-  }
+  DBImpl* dbfull() { return reinterpret_cast<DBImpl*>(db_); }

  void CreateColumnFamilies(const std::vector<std::string>& cfs,
                            const Options& options);
@@ -525,9 +607,8 @@ class DBTestBase : public testing::Test {
  void ReopenWithColumnFamilies(const std::vector<std::string>& cfs,
                                const Options& options);

-  Status TryReopenWithColumnFamilies(
-      const std::vector<std::string>& cfs,
-      const std::vector<Options>& options);
+  Status TryReopenWithColumnFamilies(const std::vector<std::string>& cfs,
+                                     const std::vector<Options>& options);

  Status TryReopenWithColumnFamilies(const std::vector<std::string>& cfs,
                                     const Options& options);
@@ -574,15 +655,19 @@ class DBTestBase : public testing::Test {

  std::string AllEntriesFor(const Slice& user_key, int cf = 0);

+#ifndef ROCKSDB_LITE
  int NumSortedRuns(int cf = 0);

  uint64_t TotalSize(int cf = 0);

-  int NumTableFilesAtLevel(int level, int cf = 0);
-
  uint64_t SizeAtLevel(int level);

-  int TotalLiveFiles(int cf = 0);
+  size_t TotalLiveFiles(int cf = 0);
+
+  size_t CountLiveFiles();
+#endif  // ROCKSDB_LITE
+
+  int NumTableFilesAtLevel(int level, int cf = 0);

  int TotalTableFiles(int cf = 0, int levels = -1);

@@ -591,8 +676,6 @@ class DBTestBase : public testing::Test {

  size_t CountFiles();

-  size_t CountLiveFiles();
-
  uint64_t Size(const Slice& start, const Slice& limit, int cf = 0);

  void Compact(int cf, const Slice& start, const Slice& limit,
@@ -627,6 +710,9 @@ class DBTestBase : public testing::Test {

  void GenerateNewFile(int fd, Random* rnd, int* key_idx, bool nowait = false);

+  static const int kNumKeysByGenerateNewRandomFile;
+  static const int KNumKeysByGenerateNewFile = 100;
+
  void GenerateNewRandomFile(Random* rnd, bool nowait = false);

  std::string IterStatus(Iterator* iter);
@@ -643,21 +729,21 @@ class DBTestBase : public testing::Test {
  //   sets newValue with delta
  // If previous value is not empty,
  //   updates previous value with 'b' string of previous value size - 1.
-  static UpdateStatus updateInPlaceSmallerSize(
-      char* prevValue, uint32_t* prevSize,
-      Slice delta, std::string* newValue);
+  static UpdateStatus updateInPlaceSmallerSize(char* prevValue,
+                                               uint32_t* prevSize, Slice delta,
+                                               std::string* newValue);

-  static UpdateStatus updateInPlaceSmallerVarintSize(
-      char* prevValue, uint32_t* prevSize,
-      Slice delta, std::string* newValue);
+  static UpdateStatus updateInPlaceSmallerVarintSize(char* prevValue,
+                                                     uint32_t* prevSize,
+                                                     Slice delta,
+                                                     std::string* newValue);

-  static UpdateStatus updateInPlaceLargerSize(
-      char* prevValue, uint32_t* prevSize,
-      Slice delta, std::string* newValue);
+  static UpdateStatus updateInPlaceLargerSize(char* prevValue,
+                                              uint32_t* prevSize, Slice delta,
+                                              std::string* newValue);

-  static UpdateStatus updateInPlaceNoAction(
-      char* prevValue, uint32_t* prevSize,
-      Slice delta, std::string* newValue);
+  static UpdateStatus updateInPlaceNoAction(char* prevValue, uint32_t* prevSize,
+                                            Slice delta, std::string* newValue);

  // Utility method to test InplaceUpdate
  void validateNumberOfEntries(int numValues, int cf = 0);
@@ -7,13 +7,18 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file. See the AUTHORS file for names of contributors.

+#include "db/db_test_util.h"
 #include "port/stack_trace.h"
-#include "util/db_test_util.h"
-#if !(defined NDEBUG) || !defined(OS_WIN)
+#if !defined(ROCKSDB_LITE)
 #include "util/sync_point.h"

 namespace rocksdb {

+static uint64_t TestGetTickerCount(const Options& options,
+                                   Tickers ticker_type) {
+  return options.statistics->getTickerCount(ticker_type);
+}
+
 static std::string CompressibleString(Random* rnd, int len) {
  std::string r;
  test::CompressibleString(rnd, 0.8, len, &r);
@@ -22,12 +27,16 @@ static std::string CompressibleString(Random* rnd, int len) {

 class DBTestUniversalCompactionBase
    : public DBTestBase,
-      public ::testing::WithParamInterface<int> {
+      public ::testing::WithParamInterface<std::tuple<int, bool>> {
 public:
  explicit DBTestUniversalCompactionBase(
      const std::string& path) : DBTestBase(path) {}
-  virtual void SetUp() override { num_levels_ = GetParam(); }
+  virtual void SetUp() override {
+    num_levels_ = std::get<0>(GetParam());
+    exclusive_manual_compaction_ = std::get<1>(GetParam());
+  }
  int num_levels_;
+  bool exclusive_manual_compaction_;
 };

 class DBTestUniversalCompaction : public DBTestUniversalCompactionBase {
@@ -112,6 +121,101 @@ class DelayFilterFactory : public CompactionFilterFactory {
 };
 }  // namespace

+// Make sure we don't trigger a problem if the trigger conditon is given
+// to be 0, which is invalid.
+TEST_P(DBTestUniversalCompaction, UniversalCompactionSingleSortedRun) {
+  Options options;
+  options = CurrentOptions(options);
+
+  options.compaction_style = kCompactionStyleUniversal;
+  options.num_levels = num_levels_;
+  // Config universal compaction to always compact to one single sorted run.
+  options.level0_file_num_compaction_trigger = 0;
+  options.compaction_options_universal.size_ratio = 10;
+  options.compaction_options_universal.min_merge_width = 2;
+  options.compaction_options_universal.max_size_amplification_percent = 1;
+
+  options.write_buffer_size = 105 << 10;  // 105KB
+  options.arena_block_size = 4 << 10;
+  options.target_file_size_base = 32 << 10;  // 32KB
+  // trigger compaction if there are >= 4 files
+  KeepFilterFactory* filter = new KeepFilterFactory(true);
+  filter->expect_manual_compaction_.store(false);
+  options.compaction_filter_factory.reset(filter);
+
+  DestroyAndReopen(options);
+  ASSERT_EQ(1, db_->GetOptions().level0_file_num_compaction_trigger);
+
+  Random rnd(301);
+  int key_idx = 0;
+
+  filter->expect_full_compaction_.store(true);
+
+  for (int num = 0; num < 16; num++) {
+    // Write 100KB file. And immediately it should be compacted to one file.
+    GenerateNewFile(&rnd, &key_idx);
+    dbfull()->TEST_WaitForCompact();
+    ASSERT_EQ(NumSortedRuns(0), 1);
+  }
+}
+
+TEST_P(DBTestUniversalCompaction, OptimizeFiltersForHits) {
+  Options options;
+  options = CurrentOptions(options);
+  options.compaction_style = kCompactionStyleUniversal;
+  options.compaction_options_universal.size_ratio = 5;
+  options.num_levels = num_levels_;
+  options.write_buffer_size = 105 << 10;  // 105KB
+  options.arena_block_size = 4 << 10;
+  options.target_file_size_base = 32 << 10;  // 32KB
+  // trigger compaction if there are >= 4 files
+  options.level0_file_num_compaction_trigger = 4;
+  BlockBasedTableOptions bbto;
+  bbto.cache_index_and_filter_blocks = true;
+  bbto.filter_policy.reset(NewBloomFilterPolicy(10, false));
+  bbto.whole_key_filtering = true;
+  options.table_factory.reset(NewBlockBasedTableFactory(bbto));
+  options.optimize_filters_for_hits = true;
+  options.statistics = rocksdb::CreateDBStatistics();
+  options.memtable_factory.reset(new SpecialSkipListFactory(3));
+
+  DestroyAndReopen(options);
+
+  // block compaction from happening
+  env_->SetBackgroundThreads(1, Env::LOW);
+  test::SleepingBackgroundTask sleeping_task_low;
+  env_->Schedule(&test::SleepingBackgroundTask::DoSleepTask, &sleeping_task_low,
+                 Env::Priority::LOW);
+
+  Put("", "");
+  for (int num = 0; num < options.level0_file_num_compaction_trigger; num++) {
+    Put(Key(num * 10), "val");
+    Put(Key(30 + num * 10), "val");
+    Put(Key(60 + num * 10), "val");
+
+    dbfull()->TEST_WaitForFlushMemTable();
+  }
+
+  // Query set of non existing keys
+  for (int i = 5; i < 90; i += 10) {
+    ASSERT_EQ(Get(Key(i)), "NOT_FOUND");
+  }
+
+  // Make sure bloom filter is used at least once.
+  ASSERT_GT(TestGetTickerCount(options, BLOOM_FILTER_USEFUL), 0);
+  auto prev_counter = TestGetTickerCount(options, BLOOM_FILTER_USEFUL);
+
+  // Unblock compaction and wait it for happening.
+  sleeping_task_low.WakeUp();
+  dbfull()->TEST_WaitForCompact();
+
+  // The same queries will not trigger bloom filter
+  for (int i = 5; i < 90; i += 10) {
+    ASSERT_EQ(Get(Key(i)), "NOT_FOUND");
+  }
+  ASSERT_EQ(prev_counter, TestGetTickerCount(options, BLOOM_FILTER_USEFUL));
+}
+
 // TODO(kailiu) The tests on UniversalCompaction has some issues:
 //  1. A lot of magic numbers ("11" or "12").
 //  2. Made assumption on the memtable flush conditions, which may change from
@@ -119,6 +223,7 @@ class DelayFilterFactory : public CompactionFilterFactory {
 TEST_P(DBTestUniversalCompaction, UniversalCompactionTrigger) {
  Options options;
  options.compaction_style = kCompactionStyleUniversal;
+  options.compaction_options_universal.size_ratio = 5;
  options.num_levels = num_levels_;
  options.write_buffer_size = 105 << 10;  // 105KB
  options.arena_block_size = 4 << 10;
@@ -367,6 +472,7 @@ TEST_P(DBTestUniversalCompaction, UniversalCompactionTargetLevel) {
  CompactRangeOptions compact_options;
  compact_options.change_level = true;
  compact_options.target_level = 4;
+  compact_options.exclusive_manual_compaction = exclusive_manual_compaction_;
  db_->CompactRange(compact_options, nullptr, nullptr);
  ASSERT_EQ("0,0,0,0,1", FilesPerLevel(0));
 }
@@ -459,7 +565,8 @@ TEST_P(DBTestUniversalCompactionMultiLevels, UniversalCompactionTrivialMove) {

 INSTANTIATE_TEST_CASE_P(DBTestUniversalCompactionMultiLevels,
                        DBTestUniversalCompactionMultiLevels,
-                        ::testing::Values(3, 20));
+                        ::testing::Combine(::testing::Values(3, 20),
+                                           ::testing::Bool()));

 class DBTestUniversalCompactionParallel :
    public DBTestUniversalCompactionBase {
@@ -532,7 +639,8 @@ TEST_P(DBTestUniversalCompactionParallel, UniversalCompactionParallel) {

 INSTANTIATE_TEST_CASE_P(DBTestUniversalCompactionParallel,
                        DBTestUniversalCompactionParallel,
-                        ::testing::Values(1, 10));
+                        ::testing::Combine(::testing::Values(1, 10),
+                                           ::testing::Bool()));

 TEST_P(DBTestUniversalCompaction, UniversalCompactionOptions) {
  Options options;
@@ -851,7 +959,10 @@ TEST_P(DBTestUniversalCompaction, UniversalCompactionFourPaths) {
  options.db_paths.emplace_back(dbname_ + "_2", 300 * 1024);
  options.db_paths.emplace_back(dbname_ + "_3", 500 * 1024);
  options.db_paths.emplace_back(dbname_ + "_4", 1024 * 1024 * 1024);
+  options.memtable_factory.reset(
+      new SpecialSkipListFactory(KNumKeysByGenerateNewFile - 1));
  options.compaction_style = kCompactionStyleUniversal;
+  options.compaction_options_universal.size_ratio = 5;
  options.write_buffer_size = 110 << 10;  // 105KB
  options.arena_block_size = 4 << 10;
  options.level0_file_num_compaction_trigger = 2;
@@ -968,13 +1079,15 @@ TEST_P(DBTestUniversalCompaction, IncreaseUniversalCompactionNumLevels) {
  int max_key1 = 200;
  int max_key2 = 600;
  int max_key3 = 800;
+  const int KNumKeysPerFile = 10;

  // Stage 1: open a DB with universal compaction, num_levels=1
  Options options = CurrentOptions();
  options.compaction_style = kCompactionStyleUniversal;
  options.num_levels = 1;
-  options.write_buffer_size = 100 << 10;  // 100KB
+  options.write_buffer_size = 200 << 10;  // 200KB
  options.level0_file_num_compaction_trigger = 3;
+  options.memtable_factory.reset(new SpecialSkipListFactory(KNumKeysPerFile));
  options = CurrentOptions(options);
  CreateAndReopenWithCF({"pikachu"}, options);

@@ -1019,6 +1132,7 @@ TEST_P(DBTestUniversalCompaction, IncreaseUniversalCompactionNumLevels) {
  CompactRangeOptions compact_options;
  compact_options.change_level = true;
  compact_options.target_level = 0;
+  compact_options.exclusive_manual_compaction = exclusive_manual_compaction_;
  dbfull()->CompactRange(compact_options, handles_[1], nullptr, nullptr);
  // Need to restart it once to remove higher level records in manifest.
  ReopenWithColumnFamilies({"default", "pikachu"}, options);
@@ -1047,11 +1161,14 @@ TEST_P(DBTestUniversalCompaction, UniversalCompactionSecondPathRatio) {
  options.db_paths.emplace_back(dbname_, 500 * 1024);
  options.db_paths.emplace_back(dbname_ + "_2", 1024 * 1024 * 1024);
  options.compaction_style = kCompactionStyleUniversal;
+  options.compaction_options_universal.size_ratio = 5;
  options.write_buffer_size = 110 << 10;  // 105KB
  options.arena_block_size = 4 * 1024;
  options.arena_block_size = 4 << 10;
  options.level0_file_num_compaction_trigger = 2;
  options.num_levels = 1;
+  options.memtable_factory.reset(
+      new SpecialSkipListFactory(KNumKeysByGenerateNewFile - 1));
  options = CurrentOptions(options);

  std::vector<std::string> filenames;
@@ -1139,7 +1256,8 @@ TEST_P(DBTestUniversalCompaction, UniversalCompactionSecondPathRatio) {
 }

 INSTANTIATE_TEST_CASE_P(UniversalCompactionNumLevels, DBTestUniversalCompaction,
-                        ::testing::Values(1, 3, 5));
+                        ::testing::Combine(::testing::Values(1, 3, 5),
+                                           ::testing::Bool()));

 class DBTestUniversalManualCompactionOutputPathId
    : public DBTestUniversalCompactionBase {
@@ -1171,6 +1289,7 @@ TEST_P(DBTestUniversalManualCompactionOutputPathId,
  // Full compaction to DB path 0
  CompactRangeOptions compact_options;
  compact_options.target_path_id = 1;
+  compact_options.exclusive_manual_compaction = exclusive_manual_compaction_;
  db_->CompactRange(compact_options, handles_[1], nullptr, nullptr);
  ASSERT_EQ(1, TotalLiveFiles(1));
  ASSERT_EQ(0, GetSstFileCount(options.db_paths[0].path));
@@ -1193,6 +1312,7 @@ TEST_P(DBTestUniversalManualCompactionOutputPathId,

  // Full compaction to DB path 0
  compact_options.target_path_id = 0;
+  compact_options.exclusive_manual_compaction = exclusive_manual_compaction_;
  db_->CompactRange(compact_options, handles_[1], nullptr, nullptr);
  ASSERT_EQ(1, TotalLiveFiles(1));
  ASSERT_EQ(1, GetSstFileCount(options.db_paths[0].path));
@@ -1200,20 +1320,22 @@ TEST_P(DBTestUniversalManualCompactionOutputPathId,

  // Fail when compacting to an invalid path ID
  compact_options.target_path_id = 2;
+  compact_options.exclusive_manual_compaction = exclusive_manual_compaction_;
  ASSERT_TRUE(db_->CompactRange(compact_options, handles_[1], nullptr, nullptr)
                  .IsInvalidArgument());
 }

 INSTANTIATE_TEST_CASE_P(DBTestUniversalManualCompactionOutputPathId,
                        DBTestUniversalManualCompactionOutputPathId,
-                        ::testing::Values(1, 8));
+                        ::testing::Combine(::testing::Values(1, 8),
+                                           ::testing::Bool()));

 }  // namespace rocksdb

-#endif  // !(defined NDEBUG) || !defined(OS_WIN)
+#endif  // !defined(ROCKSDB_LITE)

 int main(int argc, char** argv) {
-#if !(defined NDEBUG) || !defined(OS_WIN)
+#if !defined(ROCKSDB_LITE)
  rocksdb::port::InstallStackTraceHandler();
  ::testing::InitGoogleTest(&argc, argv);
  return RUN_ALL_TESTS();
@@ -7,11 +7,9 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file. See the AUTHORS file for names of contributors.

+#include "db/db_test_util.h"
 #include "port/stack_trace.h"
-#include "util/db_test_util.h"
-#if !(defined NDEBUG) || !defined(OS_WIN)
 #include "util/sync_point.h"
-#endif

 namespace rocksdb {
 class DBWALTest : public DBTestBase {
@@ -70,7 +68,6 @@ TEST_F(DBWALTest, RollLog) {
  } while (ChangeOptions());
 }

-#if !(defined NDEBUG) || !defined(OS_WIN)
 TEST_F(DBWALTest, SyncWALNotBlockWrite) {
  Options options = CurrentOptions();
  options.max_write_buffer_number = 4;
@@ -130,15 +127,10 @@ TEST_F(DBWALTest, SyncWALNotWaitWrite) {
  ASSERT_EQ(Get("foo2"), "bar2");
  rocksdb::SyncPoint::GetInstance()->DisableProcessing();
 }
-#endif
 }  // namespace rocksdb

 int main(int argc, char** argv) {
-#if !(defined NDEBUG) || !defined(OS_WIN)
  rocksdb::port::InstallStackTraceHandler();
  ::testing::InitGoogleTest(&argc, argv);
  return RUN_ALL_TESTS();
-#else
-  return 0;
-#endif
 }
@@ -271,7 +271,8 @@ inline LookupKey::~LookupKey() {

 class IterKey {
 public:
-  IterKey() : key_(space_), buf_size_(sizeof(space_)), key_size_(0) {}
+  IterKey()
+      : buf_(space_), buf_size_(sizeof(space_)), key_(buf_), key_size_(0) {}

  ~IterKey() { ResetBuffer(); }

@@ -293,31 +294,41 @@ class IterKey {
  void TrimAppend(const size_t shared_len, const char* non_shared_data,
                  const size_t non_shared_len) {
    assert(shared_len <= key_size_);
-
    size_t total_size = shared_len + non_shared_len;
-    if (total_size <= buf_size_) {
-      key_size_ = total_size;
-    } else {
+
+    if (IsKeyPinned() /* key is not in buf_ */) {
+      // Copy the key from external memory to buf_ (copy shared_len bytes)
+      EnlargeBufferIfNeeded(total_size);
+      memcpy(buf_, key_, shared_len);
+    } else if (total_size > buf_size_) {
      // Need to allocate space, delete previous space
      char* p = new char[total_size];
      memcpy(p, key_, shared_len);

-      if (key_ != space_) {
-        delete[] key_;
+      if (buf_ != space_) {
+        delete[] buf_;
      }

-      key_ = p;
-      key_size_ = total_size;
+      buf_ = p;
      buf_size_ = total_size;
    }

-    memcpy(key_ + shared_len, non_shared_data, non_shared_len);
+    memcpy(buf_ + shared_len, non_shared_data, non_shared_len);
+    key_ = buf_;
+    key_size_ = total_size;
  }

-  Slice SetKey(const Slice& key) {
+  Slice SetKey(const Slice& key, bool copy = true) {
    size_t size = key.size();
-    EnlargeBufferIfNeeded(size);
-    memcpy(key_, key.data(), size);
+    if (copy) {
+      // Copy key to buf_
+      EnlargeBufferIfNeeded(size);
+      memcpy(buf_, key.data(), size);
+      key_ = buf_;
+    } else {
+      // Update key_ to point to external memory
+      key_ = key.data();
+    }
    key_size_ = size;
    return Slice(key_, key_size_);
  }
@@ -335,11 +346,14 @@ class IterKey {
  // Update the sequence number in the internal key.  Guarantees not to
  // invalidate slices to the key (and the user key).
  void UpdateInternalKey(uint64_t seq, ValueType t) {
+    assert(!IsKeyPinned());
    assert(key_size_ >= 8);
    uint64_t newval = (seq << 8) | t;
-    EncodeFixed64(&key_[key_size_ - 8], newval);
+    EncodeFixed64(&buf_[key_size_ - 8], newval);
  }

+  bool IsKeyPinned() const { return (key_ != buf_); }
+
  void SetInternalKey(const Slice& key_prefix, const Slice& user_key,
                      SequenceNumber s,
                      ValueType value_type = kValueTypeForSeek) {
@@ -347,10 +361,12 @@ class IterKey {
    size_t usize = user_key.size();
    EnlargeBufferIfNeeded(psize + usize + sizeof(uint64_t));
    if (psize > 0) {
-      memcpy(key_, key_prefix.data(), psize);
+      memcpy(buf_, key_prefix.data(), psize);
    }
-    memcpy(key_ + psize, user_key.data(), usize);
-    EncodeFixed64(key_ + usize + psize, PackSequenceAndType(s, value_type));
+    memcpy(buf_ + psize, user_key.data(), usize);
+    EncodeFixed64(buf_ + usize + psize, PackSequenceAndType(s, value_type));
+
+    key_ = buf_;
    key_size_ = psize + usize + sizeof(uint64_t);
  }

@@ -377,20 +393,22 @@ class IterKey {
  void EncodeLengthPrefixedKey(const Slice& key) {
    auto size = key.size();
    EnlargeBufferIfNeeded(size + static_cast<size_t>(VarintLength(size)));
-    char* ptr = EncodeVarint32(key_, static_cast<uint32_t>(size));
+    char* ptr = EncodeVarint32(buf_, static_cast<uint32_t>(size));
    memcpy(ptr, key.data(), size);
+    key_ = buf_;
  }

 private:
-  char* key_;
+  char* buf_;
  size_t buf_size_;
+  const char* key_;
  size_t key_size_;
  char space_[32];  // Avoid allocation for short keys

  void ResetBuffer() {
-    if (key_ != space_) {
-      delete[] key_;
-      key_ = space_;
+    if (buf_ != space_) {
+      delete[] buf_;
+      buf_ = space_;
    }
    buf_size_ = sizeof(space_);
    key_size_ = 0;
@@ -407,7 +425,7 @@ class IterKey {
    if (key_size > buf_size_) {
      // Need to enlarge the buffer.
      ResetBuffer();
-      key_ = new char[key_size];
+      buf_ = new char[key_size];
      buf_size_ = key_size;
    }
  }
@@ -74,6 +74,7 @@ class DeleteFileTest : public testing::Test {

  void CloseDB() {
    delete db_;
+    db_ = nullptr;
  }

  void AddKeys(int numkeys, int startkey = 0) {
@@ -8,7 +8,10 @@
 namespace rocksdb {

 namespace {
-inline double SafeDivide(double a, double b) { return b == 0.0 ? 0 : a / b; }
+template<class T>
+inline T SafeDivide(T a, T b) {
+  return b == 0 ? 0 : a / b;
+}
 }  // namespace

 void EventHelpers::AppendCurrentTime(JSONWriter* jwriter) {
@@ -53,7 +56,7 @@ void EventHelpers::LogAndNotifyTableFileCreation(
                info.table_properties.filter_policy_name;

    // user collected properties
-    for (const auto& prop : info.table_properties.user_collected_properties) {
+    for (const auto& prop : info.table_properties.readable_properties) {
      jwriter << prop.first << prop.second;
    }
    jwriter.EndObject();
@@ -11,8 +11,6 @@
 // the last "sync". It then checks for data loss errors by purposely dropping
 // file data (or entire files) not protected by a "sync".

-#if !(defined NDEBUG) || !defined(OS_WIN)
-
 #include <map>
 #include <set>
 #include "db/db_impl.h"
@@ -647,18 +645,17 @@ class FaultInjectionTest : public testing::Test,
    return test::RandomString(&r, kValueSize, storage);
  }

-  Status OpenDB() {
-    delete db_;
-    db_ = NULL;
-    env_->ResetState();
-    return DB::Open(options_, dbname_, &db_);
-  }
-
  void CloseDB() {
    delete db_;
    db_ = NULL;
  }

+  Status OpenDB() {
+    CloseDB();
+    env_->ResetState();
+    return DB::Open(options_, dbname_, &db_);
+  }
+
  void DeleteAllData() {
    Iterator* iter = db_->NewIterator(ReadOptions());
    WriteOptions options;
@@ -786,6 +783,7 @@ TEST_P(FaultInjectionTest, WriteOptionSyncTest) {
  // Block the job queue to prevent flush job from running.
  env_->Schedule(&test::SleepingBackgroundTask::DoSleepTask, &sleeping_task_low,
                 Env::Priority::HIGH);
+  sleeping_task_low.WaitUntilSleeping();

  WriteOptions write_options;
  write_options.sync = false;
@@ -869,6 +867,7 @@ TEST_P(FaultInjectionTest, ManualLogSyncTest) {
  // Block the job queue to prevent flush job from running.
  env_->Schedule(&test::SleepingBackgroundTask::DoSleepTask, &sleeping_task_low,
                 Env::Priority::HIGH);
+  sleeping_task_low.WaitUntilSleeping();

  WriteOptions write_options;
  write_options.sync = false;
@@ -902,13 +901,7 @@ INSTANTIATE_TEST_CASE_P(FaultTest, FaultInjectionTest, ::testing::Bool());

 }  // namespace rocksdb

-#endif // #if !(defined NDEBUG) || !defined(OS_WIN)
-
 int main(int argc, char** argv) {
-#if !(defined NDEBUG) || !defined(OS_WIN)
  ::testing::InitGoogleTest(&argc, argv);
  return RUN_ALL_TESTS();
-#else
-  return 0;
-#endif
 }
@@ -26,9 +26,9 @@ struct FileLevel;
 // The file tree structure in Version is prebuilt and the range of each file
 // is known. On Version::Get(), it uses binary search to find a potential file
 // and then check if a target key can be found in the file by comparing the key
-// to each file's smallest and largest key. The results of these comparisions
+// to each file's smallest and largest key. The results of these comparisons
 // can be reused beyond checking if a key falls into a file's range.
-// With some pre-calculated knowledge, each key comparision that has been done
+// With some pre-calculated knowledge, each key comparison that has been done
 // can serve as a hint to narrow down further searches: if a key compared to
 // be smaller than a file's smallest or largest, that comparison can be used
 // to find out the right bound of next binary search. Similarly, if a key
@@ -48,7 +48,7 @@ class FileIndexer {
  size_t LevelIndexSize(size_t level) const;

  // Return a file index range in the next level to search for a key based on
-  // smallest and largest key comparision for the current file specified by
+  // smallest and largest key comparison for the current file specified by
  // level and file_index. When *left_index < *right_index, both index should
  // be valid and fit in the vector size.
  void GetNextLevelIndex(const size_t level, const size_t file_index,
@@ -21,6 +21,8 @@
 #include "util/file_reader_writer.h"
 #include "util/logging.h"
 #include "util/stop_watch.h"
+#include "util/string_util.h"
+#include "util/sync_point.h"

 namespace rocksdb {

@@ -46,8 +48,9 @@ static size_t GetInfoLogPrefix(const std::string& path, char* dest, int len) {
        path[i] == '_'){
      dest[write_idx++] = path[i];
    } else {
-      if (i > 0)
+      if (i > 0) {
        dest[write_idx++] = '_';
+      }
    }
    i++;
  }
@@ -145,7 +148,7 @@ std::string LockFileName(const std::string& dbname) {
 }

 std::string TempFileName(const std::string& dbname, uint64_t number) {
-  return MakeFileName(dbname, number, "dbtmp");
+  return MakeFileName(dbname, number, kTempFileNameSuffix.c_str());
 }

 InfoLogPrefix::InfoLogPrefix(bool has_log_dir,
@@ -185,6 +188,21 @@ std::string OldInfoLogFileName(const std::string& dbname, uint64_t ts,
  return log_dir + "/" + info_log_prefix.buf + ".old." + buf;
 }

+std::string OptionsFileName(const std::string& dbname, uint64_t file_num) {
+  char buffer[256];
+  snprintf(buffer, sizeof(buffer), "%s%06" PRIu64,
+           kOptionsFileNamePrefix.c_str(), file_num);
+  return dbname + "/" + buffer;
+}
+
+std::string TempOptionsFileName(const std::string& dbname, uint64_t file_num) {
+  char buffer[256];
+  snprintf(buffer, sizeof(buffer), "%s%06" PRIu64 ".%s",
+           kOptionsFileNamePrefix.c_str(), file_num,
+           kTempFileNameSuffix.c_str());
+  return dbname + "/" + buffer;
+}
+
 std::string MetaDatabaseName(const std::string& dbname, uint64_t number) {
  char buf[100];
  snprintf(buf, sizeof(buf), "/METADB-%llu",
@@ -205,6 +223,8 @@ std::string IdentityFileName(const std::string& dbname) {
 //    dbname/MANIFEST-[0-9]+
 //    dbname/[0-9]+.(log|sst)
 //    dbname/METADB-[0-9]+
+//    dbname/OPTIONS-[0-9]+
+//    dbname/OPTIONS-[0-9]+.dbtmp
 //    Disregards / at the beginning
 bool ParseFileName(const std::string& fname,
                   uint64_t* number,
@@ -267,6 +287,21 @@ bool ParseFileName(const std::string& fname, uint64_t* number,
    }
    *type = kMetaDatabase;
    *number = num;
+  } else if (rest.starts_with(kOptionsFileNamePrefix)) {
+    uint64_t ts_suffix;
+    bool is_temp_file = false;
+    rest.remove_prefix(kOptionsFileNamePrefix.size());
+    const std::string kTempFileNameSuffixWithDot =
+        std::string(".") + kTempFileNameSuffix;
+    if (rest.ends_with(kTempFileNameSuffixWithDot)) {
+      rest.remove_suffix(kTempFileNameSuffixWithDot.size());
+      is_temp_file = true;
+    }
+    if (!ConsumeDecimalNumber(&rest, &ts_suffix)) {
+      return false;
+    }
+    *number = ts_suffix;
+    *type = is_temp_file ? kTempFile : kOptionsFile;
  } else {
    // Avoid strtoull() to keep filename format independent of the
    // current locale
@@ -301,7 +336,7 @@ bool ParseFileName(const std::string& fname, uint64_t* number,
    } else if (suffix == Slice(kRocksDbTFileExt) ||
               suffix == Slice(kLevelDbTFileExt)) {
      *type = kTableFile;
-    } else if (suffix == Slice("dbtmp")) {
+    } else if (suffix == Slice(kTempFileNameSuffix)) {
      *type = kTempFile;
    } else {
      return false;
@@ -322,7 +357,9 @@ Status SetCurrentFile(Env* env, const std::string& dbname,
  std::string tmp = TempFileName(dbname, descriptor_number);
  Status s = WriteStringToFile(env, contents.ToString() + "\n", tmp, true);
  if (s.ok()) {
+    TEST_KILL_RANDOM("SetCurrentFile:0", rocksdb_kill_odds * REDUCE_ODDS2);
    s = env->RenameFile(tmp, CurrentFileName(dbname));
+    TEST_KILL_RANDOM("SetCurrentFile:1", rocksdb_kill_odds * REDUCE_ODDS2);
  }
  if (s.ok()) {
    if (directory_to_fsync != nullptr) {
@@ -351,6 +388,7 @@ Status SetIdentityFile(Env* env, const std::string& dbname) {

 Status SyncManifest(Env* env, const DBOptions* db_options,
                    WritableFileWriter* file) {
+  TEST_KILL_RANDOM("SyncManifest:0", rocksdb_kill_odds * REDUCE_ODDS2);
  if (db_options->disableDataSync) {
    return Status::OK();
  } else {
@@ -36,7 +36,8 @@ enum FileType {
  kTempFile,
  kInfoLogFile,  // Either the current one, or an old one
  kMetaDatabase,
-  kIdentityFile
+  kIdentityFile,
+  kOptionsFile
 };

 // Return the name of the log file with the specified number
@@ -114,6 +115,19 @@ extern std::string OldInfoLogFileName(const std::string& dbname, uint64_t ts,
                                      const std::string& db_path = "",
                                      const std::string& log_dir = "");

+static const std::string kOptionsFileNamePrefix = "OPTIONS-";
+static const std::string kTempFileNameSuffix = "dbtmp";
+
+// Return a options file name given the "dbname" and file number.
+// Format:  OPTIONS-[number].dbtmp
+extern std::string OptionsFileName(const std::string& dbname,
+                                   uint64_t file_num);
+
+// Return a temp options file name given the "dbname" and file number.
+// Format:  OPTIONS-[number]
+extern std::string TempOptionsFileName(const std::string& dbname,
+                                       uint64_t file_num);
+
 // Return the name to use for a metadatabase. The result will be prefixed with
 // "dbname".
 extern std::string MetaDatabaseName(const std::string& dbname,
@@ -62,6 +62,7 @@ FlushJob::FlushJob(const std::string& dbname, ColumnFamilyData* cfd,
                   InstrumentedMutex* db_mutex,
                   std::atomic<bool>* shutting_down,
                   std::vector<SequenceNumber> existing_snapshots,
+                   SequenceNumber earliest_write_conflict_snapshot,
                   JobContext* job_context, LogBuffer* log_buffer,
                   Directory* db_directory, Directory* output_file_directory,
                   CompressionType output_compression, Statistics* stats,
@@ -75,6 +76,7 @@ FlushJob::FlushJob(const std::string& dbname, ColumnFamilyData* cfd,
      db_mutex_(db_mutex),
      shutting_down_(shutting_down),
      existing_snapshots_(std::move(existing_snapshots)),
+      earliest_write_conflict_snapshot_(earliest_write_conflict_snapshot),
      job_context_(job_context),
      log_buffer_(log_buffer),
      db_directory_(db_directory),
@@ -197,7 +199,7 @@ Status FlushJob::WriteLevel0Table(const autovector<MemTable*>& mems,
    if (log_buffer_) {
      log_buffer_->FlushBufferToLog();
    }
-    std::vector<Iterator*> memtables;
+    std::vector<InternalIterator*> memtables;
    ReadOptions ro;
    ro.total_order_seek = true;
    Arena arena;
@@ -231,13 +233,15 @@ Status FlushJob::WriteLevel0Table(const autovector<MemTable*>& mems,

      TEST_SYNC_POINT_CALLBACK("FlushJob::WriteLevel0Table:output_compression",
                               &output_compression_);
-      s = BuildTable(
-          dbname_, db_options_.env, *cfd_->ioptions(), env_options_,
-          cfd_->table_cache(), iter.get(), meta, cfd_->internal_comparator(),
-          cfd_->int_tbl_prop_collector_factories(), existing_snapshots_,
-          output_compression_, cfd_->ioptions()->compression_opts,
-          mutable_cf_options_.paranoid_file_checks, cfd_->internal_stats(),
-          Env::IO_HIGH, &info.table_properties);
+      s = BuildTable(dbname_, db_options_.env, *cfd_->ioptions(), env_options_,
+                     cfd_->table_cache(), iter.get(), meta,
+                     cfd_->internal_comparator(),
+                     cfd_->int_tbl_prop_collector_factories(), cfd_->GetID(),
+                     existing_snapshots_, earliest_write_conflict_snapshot_,
+                     output_compression_, cfd_->ioptions()->compression_opts,
+                     mutable_cf_options_.paranoid_file_checks,
+                     cfd_->internal_stats(), Env::IO_HIGH, &table_properties_);
+      info.table_properties = table_properties_;
      LogFlush(db_options_.info_log);
    }
    Log(InfoLogLevel::INFO_LEVEL, db_options_.info_log,
@@ -27,12 +27,12 @@
 #include "rocksdb/env.h"
 #include "rocksdb/memtablerep.h"
 #include "rocksdb/transaction_log.h"
+#include "table/scoped_arena_iterator.h"
 #include "util/autovector.h"
 #include "util/event_logger.h"
 #include "util/instrumented_mutex.h"
 #include "util/stop_watch.h"
 #include "util/thread_local.h"
-#include "util/scoped_arena_iterator.h"
 #include "db/internal_stats.h"
 #include "db/write_controller.h"
 #include "db/flush_scheduler.h"
@@ -58,6 +58,7 @@ class FlushJob {
           const EnvOptions& env_options, VersionSet* versions,
           InstrumentedMutex* db_mutex, std::atomic<bool>* shutting_down,
           std::vector<SequenceNumber> existing_snapshots,
+           SequenceNumber earliest_write_conflict_snapshot,
           JobContext* job_context, LogBuffer* log_buffer,
           Directory* db_directory, Directory* output_file_directory,
           CompressionType output_compression, Statistics* stats,
@@ -66,6 +67,7 @@ class FlushJob {
  ~FlushJob();

  Status Run(FileMetaData* file_meta = nullptr);
+  TableProperties GetTableProperties() const { return table_properties_; }

 private:
  void ReportStartedFlush();
@@ -82,6 +84,7 @@ class FlushJob {
  InstrumentedMutex* db_mutex_;
  std::atomic<bool>* shutting_down_;
  std::vector<SequenceNumber> existing_snapshots_;
+  SequenceNumber earliest_write_conflict_snapshot_;
  JobContext* job_context_;
  LogBuffer* log_buffer_;
  Directory* db_directory_;
@@ -89,6 +92,7 @@ class FlushJob {
  CompressionType output_compression_;
  Statistics* stats_;
  EventLogger* event_logger_;
+  TableProperties table_properties_;
 };

 }  // namespace rocksdb
@@ -61,7 +61,7 @@ class FlushJobTest : public testing::Test {
    unique_ptr<WritableFileWriter> file_writer(
        new WritableFileWriter(std::move(file), EnvOptions()));
    {
-      log::Writer log(std::move(file_writer));
+      log::Writer log(std::move(file_writer), 0, false);
      std::string record;
      new_db.EncodeTo(&record);
      s = log.AddRecord(record);
@@ -92,8 +92,8 @@ TEST_F(FlushJobTest, Empty) {
  FlushJob flush_job(dbname_, versions_->GetColumnFamilySet()->GetDefault(),
                     db_options_, *cfd->GetLatestMutableCFOptions(),
                     env_options_, versions_.get(), &mutex_, &shutting_down_,
-                     {}, &job_context, nullptr, nullptr, nullptr,
-                     kNoCompression, nullptr, &event_logger);
+                     {}, kMaxSequenceNumber, &job_context, nullptr, nullptr,
+                     nullptr, kNoCompression, nullptr, &event_logger);
  ASSERT_OK(flush_job.Run());
  job_context.Clean();
 }
@@ -131,8 +131,8 @@ TEST_F(FlushJobTest, NonEmpty) {
  FlushJob flush_job(dbname_, versions_->GetColumnFamilySet()->GetDefault(),
                     db_options_, *cfd->GetLatestMutableCFOptions(),
                     env_options_, versions_.get(), &mutex_, &shutting_down_,
-                     {}, &job_context, nullptr, nullptr, nullptr,
-                     kNoCompression, nullptr, &event_logger);
+                     {}, kMaxSequenceNumber, &job_context, nullptr, nullptr,
+                     nullptr, kNoCompression, nullptr, &event_logger);
  FileMetaData fd;
  mutex_.Lock();
  ASSERT_OK(flush_job.Run(&fd));
@@ -195,8 +195,8 @@ TEST_F(FlushJobTest, Snapshots) {
  FlushJob flush_job(dbname_, versions_->GetColumnFamilySet()->GetDefault(),
                     db_options_, *cfd->GetLatestMutableCFOptions(),
                     env_options_, versions_.get(), &mutex_, &shutting_down_,
-                     snapshots, &job_context, nullptr, nullptr, nullptr,
-                     kNoCompression, nullptr, &event_logger);
+                     snapshots, kMaxSequenceNumber, &job_context, nullptr,
+                     nullptr, nullptr, kNoCompression, nullptr, &event_logger);
  mutex_.Lock();
  ASSERT_OK(flush_job.Run());
  mutex_.Unlock();
@@ -13,51 +13,69 @@ namespace rocksdb {

 void FlushScheduler::ScheduleFlush(ColumnFamilyData* cfd) {
 #ifndef NDEBUG
-  assert(column_families_set_.find(cfd) == column_families_set_.end());
-  column_families_set_.insert(cfd);
+  {
+    std::lock_guard<std::mutex> lock(checking_mutex_);
+    assert(checking_set_.count(cfd) == 0);
+    checking_set_.insert(cfd);
+  }
 #endif  // NDEBUG
  cfd->Ref();
-  column_families_.push_back(cfd);
+  Node* node = new Node{cfd, head_.load(std::memory_order_relaxed)};
+  while (!head_.compare_exchange_strong(
+      node->next, node, std::memory_order_relaxed, std::memory_order_relaxed)) {
+    // failing CAS updates the first param, so we are already set for
+    // retry.  TakeNextColumnFamily won't happen until after another
+    // inter-thread synchronization, so we don't even need release
+    // semantics for this CAS
+  }
 }

-ColumnFamilyData* FlushScheduler::GetNextColumnFamily() {
-  ColumnFamilyData* cfd = nullptr;
-  while (column_families_.size() > 0) {
-    cfd = column_families_.front();
-    column_families_.pop_front();
-    if (cfd->IsDropped()) {
-      if (cfd->Unref()) {
-        delete cfd;
-        cfd = nullptr;
-      }
-    } else {
-      break;
+ColumnFamilyData* FlushScheduler::TakeNextColumnFamily() {
+  while (true) {
+    if (Empty()) {
+      return nullptr;
    }
-  }
-#ifndef NDEBUG
-  if (cfd != nullptr) {
-    auto itr = column_families_set_.find(cfd);
-    assert(itr != column_families_set_.end());
-    column_families_set_.erase(itr);
-  }
-#endif  // NDEBUG
-  return cfd;
-}

-bool FlushScheduler::Empty() { return column_families_.empty(); }
+    // dequeue the head
+    Node* node = head_.load(std::memory_order_relaxed);
+    head_.store(node->next, std::memory_order_relaxed);
+    ColumnFamilyData* cfd = node->column_family;
+    delete node;

-void FlushScheduler::Clear() {
-  for (auto cfd : column_families_) {
 #ifndef NDEBUG
-    auto itr = column_families_set_.find(cfd);
-    assert(itr != column_families_set_.end());
-    column_families_set_.erase(itr);
+    {
+      auto iter = checking_set_.find(cfd);
+      assert(iter != checking_set_.end());
+      checking_set_.erase(iter);
+    }
 #endif  // NDEBUG
+
+    if (!cfd->IsDropped()) {
+      // success
+      return cfd;
+    }
+
+    // no longer relevant, retry
    if (cfd->Unref()) {
      delete cfd;
    }
  }
-  column_families_.clear();
+}
+
+bool FlushScheduler::Empty() {
+  auto rv = head_.load(std::memory_order_relaxed) == nullptr;
+  assert(rv == checking_set_.empty());
+  return rv;
+}
+
+void FlushScheduler::Clear() {
+  ColumnFamilyData* cfd;
+  while ((cfd = TakeNextColumnFamily()) != nullptr) {
+    if (cfd->Unref()) {
+      delete cfd;
+    }
+  }
+  assert(Empty());
 }

 }  // namespace rocksdb
@@ -6,34 +6,42 @@
 #pragma once

 #include <stdint.h>
-#include <deque>
+#include <atomic>
+#include <mutex>
 #include <set>
-#include <vector>

 namespace rocksdb {

 class ColumnFamilyData;

-// This class is thread-compatible. It's should only be accessed from single
-// write thread (between BeginWrite() and EndWrite())
+// Unless otherwise noted, all methods on FlushScheduler should be called
+// only with the DB mutex held or from a single-threaded recovery context.
 class FlushScheduler {
 public:
-  FlushScheduler() = default;
-  ~FlushScheduler() = default;
+  FlushScheduler() : head_(nullptr) {}

+  // May be called from multiple threads at once, but not concurrent with
+  // any other method calls on this instance
  void ScheduleFlush(ColumnFamilyData* cfd);
-  // Returns Ref()-ed column family. Client needs to Unref()
-  // REQUIRES: db mutex is held (exception is single-threaded recovery)
-  ColumnFamilyData* GetNextColumnFamily();
+
+  // Removes and returns Ref()-ed column family. Client needs to Unref().
+  // Filters column families that have been dropped.
+  ColumnFamilyData* TakeNextColumnFamily();

  bool Empty();

  void Clear();

 private:
-  std::deque<ColumnFamilyData*> column_families_;
+  struct Node {
+    ColumnFamilyData* column_family;
+    Node* next;
+  };
+
+  std::atomic<Node*> head_;
 #ifndef NDEBUG
-  std::set<ColumnFamilyData*> column_families_set_;
+  std::mutex checking_mutex_;
+  std::set<ColumnFamilyData*> checking_set_;
 #endif  // NDEBUG
 };

@@ -28,7 +28,7 @@ namespace rocksdb {
 //     iter.SetFileIndex(file_index);
 //     iter.Seek(target);
 //     iter.Next()
-class LevelIterator : public Iterator {
+class LevelIterator : public InternalIterator {
 public:
  LevelIterator(const ColumnFamilyData* const cfd,
      const ReadOptions& read_options,
@@ -113,7 +113,7 @@ class LevelIterator : public Iterator {
  bool valid_;
  uint32_t file_index_;
  Status status_;
-  std::unique_ptr<Iterator> file_iter_;
+  std::unique_ptr<InternalIterator> file_iter_;
 };

 ForwardIterator::ForwardIterator(DBImpl* db, const ReadOptions& read_options,
@@ -144,12 +144,29 @@ ForwardIterator::~ForwardIterator() {
  Cleanup(true);
 }

+void ForwardIterator::SVCleanup() {
+  if (sv_ != nullptr && sv_->Unref()) {
+    // Job id == 0 means that this is not our background process, but rather
+    // user thread
+    JobContext job_context(0);
+    db_->mutex_.Lock();
+    sv_->Cleanup();
+    db_->FindObsoleteFiles(&job_context, false, true);
+    db_->mutex_.Unlock();
+    delete sv_;
+    if (job_context.HaveSomethingToDelete()) {
+      db_->PurgeObsoleteFiles(job_context);
+    }
+    job_context.Clean();
+  }
+}
+
 void ForwardIterator::Cleanup(bool release_sv) {
  if (mutable_iter_ != nullptr) {
-    mutable_iter_->~Iterator();
+    mutable_iter_->~InternalIterator();
  }
  for (auto* m : imm_iters_) {
-    m->~Iterator();
+    m->~InternalIterator();
  }
  imm_iters_.clear();
  for (auto* f : l0_iters_) {
@@ -162,20 +179,7 @@ void ForwardIterator::Cleanup(bool release_sv) {
  level_iters_.clear();

  if (release_sv) {
-    if (sv_ != nullptr && sv_->Unref()) {
-      // Job id == 0 means that this is not our background process, but rather
-      // user thread
-      JobContext job_context(0);
-      db_->mutex_.Lock();
-      sv_->Cleanup();
-      db_->FindObsoleteFiles(&job_context, false, true);
-      db_->mutex_.Unlock();
-      delete sv_;
-      if (job_context.HaveSomethingToDelete()) {
-        db_->PurgeObsoleteFiles(job_context);
-      }
-      job_context.Clean();
-    }
+    SVCleanup();
  }
 }

@@ -185,9 +189,10 @@ bool ForwardIterator::Valid() const {
 }

 void ForwardIterator::SeekToFirst() {
-  if (sv_ == nullptr ||
-      sv_ ->version_number != cfd_->GetSuperVersionNumber()) {
+  if (sv_ == nullptr) {
    RebuildIterators(true);
+  } else if (sv_->version_number != cfd_->GetSuperVersionNumber()) {
+    RenewIterators();
  } else if (immutable_status_.IsIncomplete()) {
    ResetIncompleteIterators();
  }
@@ -205,9 +210,10 @@ void ForwardIterator::Seek(const Slice& internal_key) {
  if (IsOverUpperBound(internal_key)) {
    valid_ = false;
  }
-  if (sv_ == nullptr ||
-      sv_ ->version_number != cfd_->GetSuperVersionNumber()) {
+  if (sv_ == nullptr) {
    RebuildIterators(true);
+  } else if (sv_->version_number != cfd_->GetSuperVersionNumber()) {
+    RenewIterators();
  } else if (immutable_status_.IsIncomplete()) {
    ResetIncompleteIterators();
  }
@@ -227,7 +233,9 @@ void ForwardIterator::SeekInternal(const Slice& internal_key,
  // an option to turn it off.
  if (seek_to_first || NeedToSeekImmutable(internal_key)) {
    immutable_status_ = Status::OK();
-    if (has_iter_trimmed_for_upper_bound_) {
+    if ((has_iter_trimmed_for_upper_bound_) &&
+        (cfd_->internal_comparator().InternalKeyComparator::Compare(
+             prev_key_.GetKey(), internal_key) > 0)) {
      // Some iterators are trimmed. Need to rebuild.
      RebuildIterators(true);
      // Already seeked mutable iter, so seek again
@@ -254,7 +262,7 @@ void ForwardIterator::SeekInternal(const Slice& internal_key,
    }
    const VersionStorageInfo* vstorage = sv_->current->storage_info();
    const std::vector<FileMetaData*>& l0 = vstorage->LevelFiles(0);
-    for (uint32_t i = 0; i < l0.size(); ++i) {
+    for (size_t i = 0; i < l0.size(); ++i) {
      if (!l0_iters_[i]) {
        continue;
      }
@@ -393,7 +401,11 @@ void ForwardIterator::Next() {
    std::string current_key = key().ToString();
    Slice old_key(current_key.data(), current_key.size());

-    RebuildIterators(true);
+    if (sv_ == nullptr) {
+      RebuildIterators(true);
+    } else {
+      RenewIterators();
+    }
    SeekInternal(old_key, false);
    if (!valid_ || key().compare(old_key) != 0) {
      return;
@@ -484,10 +496,81 @@ void ForwardIterator::RebuildIterators(bool refresh_sv) {
    l0_iters_.push_back(cfd_->table_cache()->NewIterator(
        read_options_, *cfd_->soptions(), cfd_->internal_comparator(), l0->fd));
  }
+  BuildLevelIterators(vstorage);
+  current_ = nullptr;
+  is_prev_set_ = false;
+}
+
+void ForwardIterator::RenewIterators() {
+  SuperVersion* svnew;
+  assert(sv_);
+  svnew = cfd_->GetReferencedSuperVersion(&(db_->mutex_));
+
+  if (mutable_iter_ != nullptr) {
+    mutable_iter_->~InternalIterator();
+  }
+  for (auto* m : imm_iters_) {
+    m->~InternalIterator();
+  }
+  imm_iters_.clear();
+
+  mutable_iter_ = svnew->mem->NewIterator(read_options_, &arena_);
+  svnew->imm->AddIterators(read_options_, &imm_iters_, &arena_);
+
+  const auto* vstorage = sv_->current->storage_info();
+  const auto& l0_files = vstorage->LevelFiles(0);
+  const auto* vstorage_new = svnew->current->storage_info();
+  const auto& l0_files_new = vstorage_new->LevelFiles(0);
+  size_t iold, inew;
+  bool found;
+  std::vector<InternalIterator*> l0_iters_new;
+  l0_iters_new.reserve(l0_files_new.size());
+
+  for (inew = 0; inew < l0_files_new.size(); inew++) {
+    found = false;
+    for (iold = 0; iold < l0_files.size(); iold++) {
+      if (l0_files[iold] == l0_files_new[inew]) {
+        found = true;
+        break;
+      }
+    }
+    if (found) {
+      if (l0_iters_[iold] == nullptr) {
+        l0_iters_new.push_back(nullptr);
+        TEST_SYNC_POINT_CALLBACK("ForwardIterator::RenewIterators:Null", this);
+      } else {
+        l0_iters_new.push_back(l0_iters_[iold]);
+        l0_iters_[iold] = nullptr;
+        TEST_SYNC_POINT_CALLBACK("ForwardIterator::RenewIterators:Copy", this);
+      }
+      continue;
+    }
+    l0_iters_new.push_back(cfd_->table_cache()->NewIterator(
+        read_options_, *cfd_->soptions(), cfd_->internal_comparator(),
+        l0_files_new[inew]->fd));
+  }
+
+  for (auto* f : l0_iters_) {
+    delete f;
+  }
+  l0_iters_.clear();
+  l0_iters_ = l0_iters_new;
+
+  for (auto* l : level_iters_) {
+    delete l;
+  }
+  level_iters_.clear();
+  BuildLevelIterators(vstorage_new);
+  current_ = nullptr;
+  is_prev_set_ = false;
+  SVCleanup();
+  sv_ = svnew;
+}
+
+void ForwardIterator::BuildLevelIterators(const VersionStorageInfo* vstorage) {
  level_iters_.reserve(vstorage->num_levels() - 1);
  for (int32_t level = 1; level < vstorage->num_levels(); ++level) {
    const auto& level_files = vstorage->LevelFiles(level);
-
    if ((level_files.empty()) ||
        ((read_options_.iterate_upper_bound != nullptr) &&
         (user_comparator_->Compare(*read_options_.iterate_upper_bound,
@@ -502,14 +585,11 @@ void ForwardIterator::RebuildIterators(bool refresh_sv) {
          new LevelIterator(cfd_, read_options_, level_files));
    }
  }
-
-  current_ = nullptr;
-  is_prev_set_ = false;
 }

 void ForwardIterator::ResetIncompleteIterators() {
  const auto& l0_files = sv_->current->storage_info()->LevelFiles(0);
-  for (uint32_t i = 0; i < l0_iters_.size(); ++i) {
+  for (size_t i = 0; i < l0_iters_.size(); ++i) {
    assert(i < l0_files.size());
    if (!l0_iters_[i] || !l0_iters_[i]->status().IsIncomplete()) {
      continue;
@@ -600,7 +680,7 @@ bool ForwardIterator::NeedToSeekImmutable(const Slice& target) {
 void ForwardIterator::DeleteCurrentIter() {
  const VersionStorageInfo* vstorage = sv_->current->storage_info();
  const std::vector<FileMetaData*>& l0 = vstorage->LevelFiles(0);
-  for (uint32_t i = 0; i < l0.size(); ++i) {
+  for (size_t i = 0; i < l0.size(); ++i) {
    if (!l0_iters_[i]) {
      continue;
    }
@@ -632,7 +712,7 @@ bool ForwardIterator::TEST_CheckDeletedIters(int* pdeleted_iters,

  const VersionStorageInfo* vstorage = sv_->current->storage_info();
  const std::vector<FileMetaData*>& l0 = vstorage->LevelFiles(0);
-  for (uint32_t i = 0; i < l0.size(); ++i) {
+  for (size_t i = 0; i < l0.size(); ++i) {
    if (!l0_iters_[i]) {
      retval = true;
      deleted_iters++;
@@ -14,6 +14,7 @@
 #include "rocksdb/iterator.h"
 #include "rocksdb/options.h"
 #include "db/dbformat.h"
+#include "table/internal_iterator.h"
 #include "util/arena.h"

 namespace rocksdb {
@@ -23,6 +24,7 @@ class Env;
 struct SuperVersion;
 class ColumnFamilyData;
 class LevelIterator;
+class VersionStorageInfo;
 struct FileMetaData;

 class MinIterComparator {
@@ -30,16 +32,15 @@ class MinIterComparator {
  explicit MinIterComparator(const Comparator* comparator) :
    comparator_(comparator) {}

-  bool operator()(Iterator* a, Iterator* b) {
+  bool operator()(InternalIterator* a, InternalIterator* b) {
    return comparator_->Compare(a->key(), b->key()) > 0;
  }
 private:
  const Comparator* comparator_;
 };

-typedef std::priority_queue<Iterator*,
-          std::vector<Iterator*>,
-          MinIterComparator> MinIterHeap;
+typedef std::priority_queue<InternalIterator*, std::vector<InternalIterator*>,
+                            MinIterComparator> MinIterHeap;

 /**
 * ForwardIterator is a special type of iterator that only supports Seek()
@@ -48,7 +49,7 @@ typedef std::priority_queue<Iterator*,
 * the iterator. At the current implementation, snapshot is taken at the
 * time Seek() is called. The Next() followed do not see new values after.
 */
-class ForwardIterator : public Iterator {
+class ForwardIterator : public InternalIterator {
 public:
  ForwardIterator(DBImpl* db, const ReadOptions& read_options,
                  ColumnFamilyData* cfd, SuperVersion* current_sv = nullptr);
@@ -74,7 +75,10 @@ class ForwardIterator : public Iterator {

 private:
  void Cleanup(bool release_sv);
+  void SVCleanup();
  void RebuildIterators(bool refresh_sv);
+  void RenewIterators();
+  void BuildLevelIterators(const VersionStorageInfo* vstorage);
  void ResetIncompleteIterators();
  void SeekInternal(const Slice& internal_key, bool seek_to_first);
  void UpdateCurrent();
@@ -94,11 +98,11 @@ class ForwardIterator : public Iterator {
  MinIterHeap immutable_min_heap_;

  SuperVersion* sv_;
-  Iterator* mutable_iter_;
-  std::vector<Iterator*> imm_iters_;
-  std::vector<Iterator*> l0_iters_;
+  InternalIterator* mutable_iter_;
+  std::vector<InternalIterator*> imm_iters_;
+  std::vector<InternalIterator*> l0_iters_;
  std::vector<LevelIterator*> level_iters_;
-  Iterator* current_;
+  InternalIterator* current_;
  bool valid_;

  // Internal iterator status; set only by one of the unsupported methods.
@@ -0,0 +1,374 @@
+//  Copyright (c) 2013, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under the BSD-style license found in the
+//  LICENSE file in the root directory of this source tree. An additional grant
+//  of patent rights can be found in the PATENTS file in the same directory.
+
+#ifndef __STDC_FORMAT_MACROS
+#define __STDC_FORMAT_MACROS
+#endif
+
+#if !defined(GFLAGS) || defined(ROCKSDB_LITE)
+#include <cstdio>
+int main() {
+  fprintf(stderr, "Please install gflags to run rocksdb tools\n");
+  return 1;
+}
+#elif defined(OS_MACOSX) || defined(OS_WIN)
+// Block forward_iterator_bench under MAC and Windows
+int main() { return 0; }
+#else
+#include <gflags/gflags.h>
+#include <semaphore.h>
+#include <atomic>
+#include <bitset>
+#include <chrono>
+#include <climits>
+#include <condition_variable>
+#include <limits>
+#include <mutex>
+#include <queue>
+#include <random>
+#include <thread>
+
+#include "rocksdb/cache.h"
+#include "rocksdb/db.h"
+#include "rocksdb/status.h"
+#include "rocksdb/table.h"
+#include "util/testharness.h"
+
+const int MAX_SHARDS = 100000;
+
+DEFINE_int32(writers, 8, "");
+DEFINE_int32(readers, 8, "");
+DEFINE_int64(rate, 100000, "");
+DEFINE_int64(value_size, 300, "");
+DEFINE_int64(shards, 1000, "");
+DEFINE_int64(memtable_size, 500000000, "");
+DEFINE_int64(block_cache_size, 300000000, "");
+DEFINE_int64(block_size, 65536, "");
+DEFINE_double(runtime, 300.0, "");
+DEFINE_bool(cache_only_first, true, "");
+DEFINE_bool(iterate_upper_bound, true, "");
+
+struct Stats {
+  char pad1[128] __attribute__((__unused__));
+  std::atomic<uint64_t> written{0};
+  char pad2[128] __attribute__((__unused__));
+  std::atomic<uint64_t> read{0};
+  std::atomic<uint64_t> cache_misses{0};
+  char pad3[128] __attribute__((__unused__));
+} stats;
+
+struct Key {
+  Key() {}
+  Key(uint64_t shard_in, uint64_t seqno_in)
+      : shard_be(htobe64(shard_in)), seqno_be(htobe64(seqno_in)) {}
+
+  uint64_t shard() const { return be64toh(shard_be); }
+  uint64_t seqno() const { return be64toh(seqno_be); }
+
+ private:
+  uint64_t shard_be;
+  uint64_t seqno_be;
+} __attribute__((__packed__));
+
+struct Reader;
+struct Writer;
+
+struct ShardState {
+  char pad1[128] __attribute__((__unused__));
+  std::atomic<uint64_t> last_written{0};
+  Writer* writer;
+  Reader* reader;
+  char pad2[128] __attribute__((__unused__));
+  std::atomic<uint64_t> last_read{0};
+  std::unique_ptr<rocksdb::Iterator> it;
+  std::unique_ptr<rocksdb::Iterator> it_cacheonly;
+  Key upper_bound;
+  rocksdb::Slice upper_bound_slice;
+  char pad3[128] __attribute__((__unused__));
+};
+
+struct Reader {
+ public:
+  explicit Reader(std::vector<ShardState>* shard_states, rocksdb::DB* db)
+      : shard_states_(shard_states), db_(db) {
+    sem_init(&sem_, 0, 0);
+    thread_ = std::thread(&Reader::run, this);
+  }
+
+  void run() {
+    while (1) {
+      sem_wait(&sem_);
+      if (done_.load()) {
+        break;
+      }
+
+      uint64_t shard;
+      {
+        std::lock_guard<std::mutex> guard(queue_mutex_);
+        assert(!shards_pending_queue_.empty());
+        shard = shards_pending_queue_.front();
+        shards_pending_queue_.pop();
+        shards_pending_set_.reset(shard);
+      }
+      readOnceFromShard(shard);
+    }
+  }
+
+  void readOnceFromShard(uint64_t shard) {
+    ShardState& state = (*shard_states_)[shard];
+    if (!state.it) {
+      // Initialize iterators
+      rocksdb::ReadOptions options;
+      options.tailing = true;
+      if (FLAGS_iterate_upper_bound) {
+        state.upper_bound = Key(shard, std::numeric_limits<uint64_t>::max());
+        state.upper_bound_slice = rocksdb::Slice(
+            (const char*)&state.upper_bound, sizeof(state.upper_bound));
+        options.iterate_upper_bound = &state.upper_bound_slice;
+      }
+
+      state.it.reset(db_->NewIterator(options));
+
+      if (FLAGS_cache_only_first) {
+        options.read_tier = rocksdb::ReadTier::kBlockCacheTier;
+        state.it_cacheonly.reset(db_->NewIterator(options));
+      }
+    }
+
+    const uint64_t upto = state.last_written.load();
+    for (rocksdb::Iterator* it : {state.it_cacheonly.get(), state.it.get()}) {
+      if (it == nullptr) {
+        continue;
+      }
+      if (state.last_read.load() >= upto) {
+        break;
+      }
+      bool need_seek = true;
+      for (uint64_t seq = state.last_read.load() + 1; seq <= upto; ++seq) {
+        if (need_seek) {
+          Key from(shard, state.last_read.load() + 1);
+          it->Seek(rocksdb::Slice((const char*)&from, sizeof(from)));
+          need_seek = false;
+        } else {
+          it->Next();
+        }
+        if (it->status().IsIncomplete()) {
+          ++::stats.cache_misses;
+          break;
+        }
+        assert(it->Valid());
+        assert(it->key().size() == sizeof(Key));
+        Key key;
+        memcpy(&key, it->key().data(), it->key().size());
+        // fprintf(stderr, "Expecting (%ld, %ld) read (%ld, %ld)\n",
+        //         shard, seq, key.shard(), key.seqno());
+        assert(key.shard() == shard);
+        assert(key.seqno() == seq);
+        state.last_read.store(seq);
+        ++::stats.read;
+      }
+    }
+  }
+
+  void onWrite(uint64_t shard) {
+    {
+      std::lock_guard<std::mutex> guard(queue_mutex_);
+      if (!shards_pending_set_.test(shard)) {
+        shards_pending_queue_.push(shard);
+        shards_pending_set_.set(shard);
+        sem_post(&sem_);
+      }
+    }
+  }
+
+  ~Reader() {
+    done_.store(true);
+    sem_post(&sem_);
+    thread_.join();
+  }
+
+ private:
+  char pad1[128] __attribute__((__unused__));
+  std::vector<ShardState>* shard_states_;
+  rocksdb::DB* db_;
+  std::thread thread_;
+  sem_t sem_;
+  std::mutex queue_mutex_;
+  std::bitset<MAX_SHARDS + 1> shards_pending_set_;
+  std::queue<uint64_t> shards_pending_queue_;
+  std::atomic<bool> done_{false};
+  char pad2[128] __attribute__((__unused__));
+};
+
+struct Writer {
+  explicit Writer(std::vector<ShardState>* shard_states, rocksdb::DB* db)
+      : shard_states_(shard_states), db_(db) {}
+
+  void start() { thread_ = std::thread(&Writer::run, this); }
+
+  void run() {
+    std::queue<std::chrono::steady_clock::time_point> workq;
+    std::chrono::steady_clock::time_point deadline(
+        std::chrono::steady_clock::now() +
+        std::chrono::nanoseconds((uint64_t)(1000000000 * FLAGS_runtime)));
+    std::vector<uint64_t> my_shards;
+    for (int i = 1; i <= FLAGS_shards; ++i) {
+      if ((*shard_states_)[i].writer == this) {
+        my_shards.push_back(i);
+      }
+    }
+
+    std::mt19937 rng{std::random_device()()};
+    std::uniform_int_distribution<int> shard_dist(
+        0, static_cast<int>(my_shards.size()) - 1);
+    std::string value(FLAGS_value_size, '*');
+
+    while (1) {
+      auto now = std::chrono::steady_clock::now();
+      if (FLAGS_runtime >= 0 && now >= deadline) {
+        break;
+      }
+      if (workq.empty()) {
+        for (int i = 0; i < FLAGS_rate; i += FLAGS_writers) {
+          std::chrono::nanoseconds offset(1000000000LL * i / FLAGS_rate);
+          workq.push(now + offset);
+        }
+      }
+      while (!workq.empty() && workq.front() < now) {
+        workq.pop();
+        uint64_t shard = my_shards[shard_dist(rng)];
+        ShardState& state = (*shard_states_)[shard];
+        uint64_t seqno = state.last_written.load() + 1;
+        Key key(shard, seqno);
+        // fprintf(stderr, "Writing (%ld, %ld)\n", shard, seqno);
+        rocksdb::Status status =
+            db_->Put(rocksdb::WriteOptions(),
+                     rocksdb::Slice((const char*)&key, sizeof(key)),
+                     rocksdb::Slice(value));
+        assert(status.ok());
+        state.last_written.store(seqno);
+        state.reader->onWrite(shard);
+        ++::stats.written;
+      }
+      std::this_thread::sleep_for(std::chrono::milliseconds(1));
+    }
+    // fprintf(stderr, "Writer done\n");
+  }
+
+  ~Writer() { thread_.join(); }
+
+ private:
+  char pad1[128] __attribute__((__unused__));
+  std::vector<ShardState>* shard_states_;
+  rocksdb::DB* db_;
+  std::thread thread_;
+  char pad2[128] __attribute__((__unused__));
+};
+
+struct StatsThread {
+  explicit StatsThread(rocksdb::DB* db)
+      : db_(db), thread_(&StatsThread::run, this) {}
+
+  void run() {
+    //    using namespace std::chrono;
+    auto tstart = std::chrono::steady_clock::now(), tlast = tstart;
+    uint64_t wlast = 0, rlast = 0;
+    while (!done_.load()) {
+      {
+        std::unique_lock<std::mutex> lock(cvm_);
+        cv_.wait_for(lock, std::chrono::seconds(1));
+      }
+      auto now = std::chrono::steady_clock::now();
+      double elapsed =
+          std::chrono::duration_cast<std::chrono::duration<double> >(
+              now - tlast).count();
+      uint64_t w = ::stats.written.load();
+      uint64_t r = ::stats.read.load();
+      fprintf(stderr,
+              "%s elapsed %4lds | written %10ld | w/s %10.0f | read %10ld | "
+              "r/s %10.0f | cache misses %10ld\n",
+              db_->GetEnv()->TimeToString(time(nullptr)).c_str(),
+              std::chrono::duration_cast<std::chrono::seconds>(now - tstart)
+                  .count(),
+              w, (w - wlast) / elapsed, r, (r - rlast) / elapsed,
+              ::stats.cache_misses.load());
+      wlast = w;
+      rlast = r;
+      tlast = now;
+    }
+  }
+
+  ~StatsThread() {
+    {
+      std::lock_guard<std::mutex> guard(cvm_);
+      done_.store(true);
+    }
+    cv_.notify_all();
+    thread_.join();
+  }
+
+ private:
+  rocksdb::DB* db_;
+  std::mutex cvm_;
+  std::condition_variable cv_;
+  std::thread thread_;
+  std::atomic<bool> done_{false};
+};
+
+int main(int argc, char** argv) {
+  GFLAGS::ParseCommandLineFlags(&argc, &argv, true);
+
+  std::mt19937 rng{std::random_device()()};
+  rocksdb::Status status;
+  std::string path = rocksdb::test::TmpDir() + "/forward_iterator_test";
+  fprintf(stderr, "db path is %s\n", path.c_str());
+  rocksdb::Options options;
+  options.create_if_missing = true;
+  options.compression = rocksdb::CompressionType::kNoCompression;
+  options.compaction_style = rocksdb::CompactionStyle::kCompactionStyleNone;
+  options.level0_slowdown_writes_trigger = 99999;
+  options.level0_stop_writes_trigger = 99999;
+  options.allow_os_buffer = false;
+  options.write_buffer_size = FLAGS_memtable_size;
+  rocksdb::BlockBasedTableOptions table_options;
+  table_options.block_cache = rocksdb::NewLRUCache(FLAGS_block_cache_size);
+  table_options.block_size = FLAGS_block_size;
+  options.table_factory.reset(
+      rocksdb::NewBlockBasedTableFactory(table_options));
+
+  status = rocksdb::DestroyDB(path, options);
+  assert(status.ok());
+  rocksdb::DB* db_raw;
+  status = rocksdb::DB::Open(options, path, &db_raw);
+  assert(status.ok());
+  std::unique_ptr<rocksdb::DB> db(db_raw);
+
+  std::vector<ShardState> shard_states(FLAGS_shards + 1);
+  std::deque<Reader> readers;
+  while (static_cast<int>(readers.size()) < FLAGS_readers) {
+    readers.emplace_back(&shard_states, db_raw);
+  }
+  std::deque<Writer> writers;
+  while (static_cast<int>(writers.size()) < FLAGS_writers) {
+    writers.emplace_back(&shard_states, db_raw);
+  }
+
+  // Each shard gets a random reader and random writer assigned to it
+  for (int i = 1; i <= FLAGS_shards; ++i) {
+    std::uniform_int_distribution<int> reader_dist(0, FLAGS_readers - 1);
+    std::uniform_int_distribution<int> writer_dist(0, FLAGS_writers - 1);
+    shard_states[i].reader = &readers[reader_dist(rng)];
+    shard_states[i].writer = &writers[writer_dist(rng)];
+  }
+
+  StatsThread stats_thread(db_raw);
+  for (Writer& w : writers) {
+    w.start();
+  }
+
+  writers.clear();
+  readers.clear();
+}
+#endif  // !defined(GFLAGS) || defined(ROCKSDB_LITE)
@@ -0,0 +1,657 @@
+//  Copyright (c) 2013, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under the BSD-style license found in the
+//  LICENSE file in the root directory of this source tree. An additional
+//  grant of patent rights can be found in the PATENTS file in the same
+//  directory.
+//
+// Copyright (c) 2011 The LevelDB Authors. All rights reserved.  Use of
+// this source code is governed by a BSD-style license that can be found
+// in the LICENSE file. See the AUTHORS file for names of contributors.
+//
+// InlineSkipList is derived from SkipList (skiplist.h), but it optimizes
+// the memory layout by requiring that the key storage be allocated through
+// the skip list instance.  For the common case of SkipList<const char*,
+// Cmp> this saves 1 pointer per skip list node and gives better cache
+// locality, at the expense of wasted padding from using AllocateAligned
+// instead of Allocate for the keys.  The unused padding will be from
+// 0 to sizeof(void*)-1 bytes, and the space savings are sizeof(void*)
+// bytes, so despite the padding the space used is always less than
+// SkipList<const char*, ..>.
+//
+// Thread safety -------------
+//
+// Writes via Insert require external synchronization, most likely a mutex.
+// InsertConcurrently can be safely called concurrently with reads and
+// with other concurrent inserts.  Reads require a guarantee that the
+// InlineSkipList will not be destroyed while the read is in progress.
+// Apart from that, reads progress without any internal locking or
+// synchronization.
+//
+// Invariants:
+//
+// (1) Allocated nodes are never deleted until the InlineSkipList is
+// destroyed.  This is trivially guaranteed by the code since we never
+// delete any skip list nodes.
+//
+// (2) The contents of a Node except for the next/prev pointers are
+// immutable after the Node has been linked into the InlineSkipList.
+// Only Insert() modifies the list, and it is careful to initialize a
+// node and use release-stores to publish the nodes in one or more lists.
+//
+// ... prev vs. next pointer ordering ...
+//
+
+#pragma once
+#include <assert.h>
+#include <stdlib.h>
+#include <atomic>
+#include "port/port.h"
+#include "util/allocator.h"
+#include "util/random.h"
+
+namespace rocksdb {
+
+template <class Comparator>
+class InlineSkipList {
+ private:
+  struct Node;
+
+ public:
+  // Create a new InlineSkipList object that will use "cmp" for comparing
+  // keys, and will allocate memory using "*allocator".  Objects allocated
+  // in the allocator must remain allocated for the lifetime of the
+  // skiplist object.
+  explicit InlineSkipList(Comparator cmp, Allocator* allocator,
+                          int32_t max_height = 12,
+                          int32_t branching_factor = 4);
+
+  // Allocates a key and a skip-list node, returning a pointer to the key
+  // portion of the node.  This method is thread-safe if the allocator
+  // is thread-safe.
+  char* AllocateKey(size_t key_size);
+
+  // Inserts a key allocated by AllocateKey, after the actual key value
+  // has been filled in.
+  //
+  // REQUIRES: nothing that compares equal to key is currently in the list.
+  // REQUIRES: no concurrent calls to INSERT
+  void Insert(const char* key);
+
+  // Like Insert, but external synchronization is not required.
+  void InsertConcurrently(const char* key);
+
+  // Returns true iff an entry that compares equal to key is in the list.
+  bool Contains(const char* key) const;
+
+  // Return estimated number of entries smaller than `key`.
+  uint64_t EstimateCount(const char* key) const;
+
+  // Iteration over the contents of a skip list
+  class Iterator {
+   public:
+    // Initialize an iterator over the specified list.
+    // The returned iterator is not valid.
+    explicit Iterator(const InlineSkipList* list);
+
+    // Change the underlying skiplist used for this iterator
+    // This enables us not changing the iterator without deallocating
+    // an old one and then allocating a new one
+    void SetList(const InlineSkipList* list);
+
+    // Returns true iff the iterator is positioned at a valid node.
+    bool Valid() const;
+
+    // Returns the key at the current position.
+    // REQUIRES: Valid()
+    const char* key() const;
+
+    // Advances to the next position.
+    // REQUIRES: Valid()
+    void Next();
+
+    // Advances to the previous position.
+    // REQUIRES: Valid()
+    void Prev();
+
+    // Advance to the first entry with a key >= target
+    void Seek(const char* target);
+
+    // Position at the first entry in list.
+    // Final state of iterator is Valid() iff list is not empty.
+    void SeekToFirst();
+
+    // Position at the last entry in list.
+    // Final state of iterator is Valid() iff list is not empty.
+    void SeekToLast();
+
+   private:
+    const InlineSkipList* list_;
+    Node* node_;
+    // Intentionally copyable
+  };
+
+ private:
+  enum MaxPossibleHeightEnum : uint16_t { kMaxPossibleHeight = 32 };
+
+  const uint16_t kMaxHeight_;
+  const uint16_t kBranching_;
+  const uint32_t kScaledInverseBranching_;
+
+  // Immutable after construction
+  Comparator const compare_;
+  Allocator* const allocator_;  // Allocator used for allocations of nodes
+
+  Node* const head_;
+
+  // Modified only by Insert().  Read racily by readers, but stale
+  // values are ok.
+  std::atomic<int> max_height_;  // Height of the entire list
+
+  // Used for optimizing sequential insert patterns.  Tricky.  prev_height_
+  // of zero means prev_ is undefined.  Otherwise: prev_[i] for i up
+  // to max_height_ - 1 (inclusive) is the predecessor of prev_[0], and
+  // prev_height_ is the height of prev_[0].  prev_[0] can only be equal
+  // to head when max_height_ and prev_height_ are both 1.
+  Node** prev_;
+  std::atomic<int32_t> prev_height_;
+
+  inline int GetMaxHeight() const {
+    return max_height_.load(std::memory_order_relaxed);
+  }
+
+  int RandomHeight();
+
+  Node* AllocateNode(size_t key_size, int height);
+
+  bool Equal(const char* a, const char* b) const {
+    return (compare_(a, b) == 0);
+  }
+
+  // Return true if key is greater than the data stored in "n".  Null n
+  // is considered infinite.
+  bool KeyIsAfterNode(const char* key, Node* n) const;
+
+  // Returns the earliest node with a key >= key.
+  // Return nullptr if there is no such node.
+  Node* FindGreaterOrEqual(const char* key) const;
+
+  // Return the latest node with a key < key.
+  // Return head_ if there is no such node.
+  // Fills prev[level] with pointer to previous node at "level" for every
+  // level in [0..max_height_-1], if prev is non-null.
+  Node* FindLessThan(const char* key, Node** prev = nullptr) const;
+
+  // Return the last node in the list.
+  // Return head_ if list is empty.
+  Node* FindLast() const;
+
+  // Traverses a single level of the list, setting *out_prev to the last
+  // node before the key and *out_next to the first node after. Assumes
+  // that the key is not present in the skip list. On entry, before should
+  // point to a node that is before the key, and after should point to
+  // a node that is after the key.  after should be nullptr if a good after
+  // node isn't conveniently available.
+  void FindLevelSplice(const char* key, Node* before, Node* after, int level,
+                       Node** out_prev, Node** out_next);
+
+  // No copying allowed
+  InlineSkipList(const InlineSkipList&);
+  InlineSkipList& operator=(const InlineSkipList&);
+};
+
+// Implementation details follow
+
+// The Node data type is more of a pointer into custom-managed memory than
+// a traditional C++ struct.  The key is stored in the bytes immediately
+// after the struct, and the next_ pointers for nodes with height > 1 are
+// stored immediately _before_ the struct.  This avoids the need to include
+// any pointer or sizing data, which reduces per-node memory overheads.
+template <class Comparator>
+struct InlineSkipList<Comparator>::Node {
+  // Stores the height of the node in the memory location normally used for
+  // next_[0].  This is used for passing data from AllocateKey to Insert.
+  void StashHeight(const int height) {
+    assert(sizeof(int) <= sizeof(next_[0]));
+    memcpy(&next_[0], &height, sizeof(int));
+  }
+
+  // Retrieves the value passed to StashHeight.  Undefined after a call
+  // to SetNext or NoBarrier_SetNext.
+  int UnstashHeight() const {
+    int rv;
+    memcpy(&rv, &next_[0], sizeof(int));
+    return rv;
+  }
+
+  const char* Key() const { return reinterpret_cast<const char*>(&next_[1]); }
+
+  // Accessors/mutators for links.  Wrapped in methods so we can add
+  // the appropriate barriers as necessary, and perform the necessary
+  // addressing trickery for storing links below the Node in memory.
+  Node* Next(int n) {
+    assert(n >= 0);
+    // Use an 'acquire load' so that we observe a fully initialized
+    // version of the returned Node.
+    return (next_[-n].load(std::memory_order_acquire));
+  }
+
+  void SetNext(int n, Node* x) {
+    assert(n >= 0);
+    // Use a 'release store' so that anybody who reads through this
+    // pointer observes a fully initialized version of the inserted node.
+    next_[-n].store(x, std::memory_order_release);
+  }
+
+  bool CASNext(int n, Node* expected, Node* x) {
+    assert(n >= 0);
+    return next_[-n].compare_exchange_strong(expected, x);
+  }
+
+  // No-barrier variants that can be safely used in a few locations.
+  Node* NoBarrier_Next(int n) {
+    assert(n >= 0);
+    return next_[-n].load(std::memory_order_relaxed);
+  }
+
+  void NoBarrier_SetNext(int n, Node* x) {
+    assert(n >= 0);
+    next_[-n].store(x, std::memory_order_relaxed);
+  }
+
+ private:
+  // next_[0] is the lowest level link (level 0).  Higher levels are
+  // stored _earlier_, so level 1 is at next_[-1].
+  std::atomic<Node*> next_[1];
+};
+
+template <class Comparator>
+inline InlineSkipList<Comparator>::Iterator::Iterator(
+    const InlineSkipList* list) {
+  SetList(list);
+}
+
+template <class Comparator>
+inline void InlineSkipList<Comparator>::Iterator::SetList(
+    const InlineSkipList* list) {
+  list_ = list;
+  node_ = nullptr;
+}
+
+template <class Comparator>
+inline bool InlineSkipList<Comparator>::Iterator::Valid() const {
+  return node_ != nullptr;
+}
+
+template <class Comparator>
+inline const char* InlineSkipList<Comparator>::Iterator::key() const {
+  assert(Valid());
+  return node_->Key();
+}
+
+template <class Comparator>
+inline void InlineSkipList<Comparator>::Iterator::Next() {
+  assert(Valid());
+  node_ = node_->Next(0);
+}
+
+template <class Comparator>
+inline void InlineSkipList<Comparator>::Iterator::Prev() {
+  // Instead of using explicit "prev" links, we just search for the
+  // last node that falls before key.
+  assert(Valid());
+  node_ = list_->FindLessThan(node_->Key());
+  if (node_ == list_->head_) {
+    node_ = nullptr;
+  }
+}
+
+template <class Comparator>
+inline void InlineSkipList<Comparator>::Iterator::Seek(const char* target) {
+  node_ = list_->FindGreaterOrEqual(target);
+}
+
+template <class Comparator>
+inline void InlineSkipList<Comparator>::Iterator::SeekToFirst() {
+  node_ = list_->head_->Next(0);
+}
+
+template <class Comparator>
+inline void InlineSkipList<Comparator>::Iterator::SeekToLast() {
+  node_ = list_->FindLast();
+  if (node_ == list_->head_) {
+    node_ = nullptr;
+  }
+}
+
+template <class Comparator>
+int InlineSkipList<Comparator>::RandomHeight() {
+  auto rnd = Random::GetTLSInstance();
+
+  // Increase height with probability 1 in kBranching
+  int height = 1;
+  while (height < kMaxHeight_ && height < kMaxPossibleHeight &&
+         rnd->Next() < kScaledInverseBranching_) {
+    height++;
+  }
+  assert(height > 0);
+  assert(height <= kMaxHeight_);
+  assert(height <= kMaxPossibleHeight);
+  return height;
+}
+
+template <class Comparator>
+bool InlineSkipList<Comparator>::KeyIsAfterNode(const char* key,
+                                                Node* n) const {
+  // nullptr n is considered infinite
+  return (n != nullptr) && (compare_(n->Key(), key) < 0);
+}
+
+template <class Comparator>
+typename InlineSkipList<Comparator>::Node*
+InlineSkipList<Comparator>::FindGreaterOrEqual(const char* key) const {
+  // Note: It looks like we could reduce duplication by implementing
+  // this function as FindLessThan(key)->Next(0), but we wouldn't be able
+  // to exit early on equality and the result wouldn't even be correct.
+  // A concurrent insert might occur after FindLessThan(key) but before
+  // we get a chance to call Next(0).
+  Node* x = head_;
+  int level = GetMaxHeight() - 1;
+  Node* last_bigger = nullptr;
+  while (true) {
+    Node* next = x->Next(level);
+    // Make sure the lists are sorted
+    assert(x == head_ || next == nullptr || KeyIsAfterNode(next->Key(), x));
+    // Make sure we haven't overshot during our search
+    assert(x == head_ || KeyIsAfterNode(key, x));
+    int cmp = (next == nullptr || next == last_bigger)
+                  ? 1
+                  : compare_(next->Key(), key);
+    if (cmp == 0 || (cmp > 0 && level == 0)) {
+      return next;
+    } else if (cmp < 0) {
+      // Keep searching in this list
+      x = next;
+    } else {
+      // Switch to next list, reuse compare_() result
+      last_bigger = next;
+      level--;
+    }
+  }
+}
+
+template <class Comparator>
+typename InlineSkipList<Comparator>::Node*
+InlineSkipList<Comparator>::FindLessThan(const char* key, Node** prev) const {
+  Node* x = head_;
+  int level = GetMaxHeight() - 1;
+  // KeyIsAfter(key, last_not_after) is definitely false
+  Node* last_not_after = nullptr;
+  while (true) {
+    Node* next = x->Next(level);
+    assert(x == head_ || next == nullptr || KeyIsAfterNode(next->Key(), x));
+    assert(x == head_ || KeyIsAfterNode(key, x));
+    if (next != last_not_after && KeyIsAfterNode(key, next)) {
+      // Keep searching in this list
+      x = next;
+    } else {
+      if (prev != nullptr) {
+        prev[level] = x;
+      }
+      if (level == 0) {
+        return x;
+      } else {
+        // Switch to next list, reuse KeyIUsAfterNode() result
+        last_not_after = next;
+        level--;
+      }
+    }
+  }
+}
+
+template <class Comparator>
+typename InlineSkipList<Comparator>::Node*
+InlineSkipList<Comparator>::FindLast() const {
+  Node* x = head_;
+  int level = GetMaxHeight() - 1;
+  while (true) {
+    Node* next = x->Next(level);
+    if (next == nullptr) {
+      if (level == 0) {
+        return x;
+      } else {
+        // Switch to next list
+        level--;
+      }
+    } else {
+      x = next;
+    }
+  }
+}
+
+template <class Comparator>
+uint64_t InlineSkipList<Comparator>::EstimateCount(const char* key) const {
+  uint64_t count = 0;
+
+  Node* x = head_;
+  int level = GetMaxHeight() - 1;
+  while (true) {
+    assert(x == head_ || compare_(x->Key(), key) < 0);
+    Node* next = x->Next(level);
+    if (next == nullptr || compare_(next->Key(), key) >= 0) {
+      if (level == 0) {
+        return count;
+      } else {
+        // Switch to next list
+        count *= kBranching_;
+        level--;
+      }
+    } else {
+      x = next;
+      count++;
+    }
+  }
+}
+
+template <class Comparator>
+InlineSkipList<Comparator>::InlineSkipList(const Comparator cmp,
+                                           Allocator* allocator,
+                                           int32_t max_height,
+                                           int32_t branching_factor)
+    : kMaxHeight_(max_height),
+      kBranching_(branching_factor),
+      kScaledInverseBranching_((Random::kMaxNext + 1) / kBranching_),
+      compare_(cmp),
+      allocator_(allocator),
+      head_(AllocateNode(0, max_height)),
+      max_height_(1),
+      prev_height_(1) {
+  assert(max_height > 0 && kMaxHeight_ == static_cast<uint32_t>(max_height));
+  assert(branching_factor > 1 &&
+         kBranching_ == static_cast<uint32_t>(branching_factor));
+  assert(kScaledInverseBranching_ > 0);
+  // Allocate the prev_ Node* array, directly from the passed-in allocator.
+  // prev_ does not need to be freed, as its life cycle is tied up with
+  // the allocator as a whole.
+  prev_ = reinterpret_cast<Node**>(
+      allocator_->AllocateAligned(sizeof(Node*) * kMaxHeight_));
+  for (int i = 0; i < kMaxHeight_; i++) {
+    head_->SetNext(i, nullptr);
+    prev_[i] = head_;
+  }
+}
+
+template <class Comparator>
+char* InlineSkipList<Comparator>::AllocateKey(size_t key_size) {
+  return const_cast<char*>(AllocateNode(key_size, RandomHeight())->Key());
+}
+
+template <class Comparator>
+typename InlineSkipList<Comparator>::Node*
+InlineSkipList<Comparator>::AllocateNode(size_t key_size, int height) {
+  auto prefix = sizeof(std::atomic<Node*>) * (height - 1);
+
+  // prefix is space for the height - 1 pointers that we store before
+  // the Node instance (next_[-(height - 1) .. -1]).  Node starts at
+  // raw + prefix, and holds the bottom-mode (level 0) skip list pointer
+  // next_[0].  key_size is the bytes for the key, which comes just after
+  // the Node.
+  char* raw = allocator_->AllocateAligned(prefix + sizeof(Node) + key_size);
+  Node* x = reinterpret_cast<Node*>(raw + prefix);
+
+  // Once we've linked the node into the skip list we don't actually need
+  // to know its height, because we can implicitly use the fact that we
+  // traversed into a node at level h to known that h is a valid level
+  // for that node.  We need to convey the height to the Insert step,
+  // however, so that it can perform the proper links.  Since we're not
+  // using the pointers at the moment, StashHeight temporarily borrow
+  // storage from next_[0] for that purpose.
+  x->StashHeight(height);
+  return x;
+}
+
+template <class Comparator>
+void InlineSkipList<Comparator>::Insert(const char* key) {
+  // InsertConcurrently often can't maintain the prev_ invariants, so
+  // it just sets prev_height_ to zero, letting us know that we should
+  // ignore it.  A relaxed load suffices here because write thread
+  // synchronization separates Insert calls from InsertConcurrently calls.
+  auto prev_height = prev_height_.load(std::memory_order_relaxed);
+
+  // fast path for sequential insertion
+  if (prev_height > 0 && !KeyIsAfterNode(key, prev_[0]->NoBarrier_Next(0)) &&
+      (prev_[0] == head_ || KeyIsAfterNode(key, prev_[0]))) {
+    assert(prev_[0] != head_ || (prev_height == 1 && GetMaxHeight() == 1));
+
+    // Outside of this method prev_[1..max_height_] is the predecessor
+    // of prev_[0], and prev_height_ refers to prev_[0].  Inside Insert
+    // prev_[0..max_height - 1] is the predecessor of key.  Switch from
+    // the external state to the internal
+    for (int i = 1; i < prev_height; i++) {
+      prev_[i] = prev_[0];
+    }
+  } else {
+    // TODO(opt): we could use a NoBarrier predecessor search as an
+    // optimization for architectures where memory_order_acquire needs
+    // a synchronization instruction.  Doesn't matter on x86
+    FindLessThan(key, prev_);
+  }
+
+  // Our data structure does not allow duplicate insertion
+  assert(prev_[0]->Next(0) == nullptr || !Equal(key, prev_[0]->Next(0)->Key()));
+
+  // Find the Node that we placed before the key in AllocateKey
+  Node* x = reinterpret_cast<Node*>(const_cast<char*>(key)) - 1;
+  int height = x->UnstashHeight();
+  assert(height >= 1 && height <= kMaxHeight_);
+
+  if (height > GetMaxHeight()) {
+    for (int i = GetMaxHeight(); i < height; i++) {
+      prev_[i] = head_;
+    }
+
+    // It is ok to mutate max_height_ without any synchronization
+    // with concurrent readers.  A concurrent reader that observes
+    // the new value of max_height_ will see either the old value of
+    // new level pointers from head_ (nullptr), or a new value set in
+    // the loop below.  In the former case the reader will
+    // immediately drop to the next level since nullptr sorts after all
+    // keys.  In the latter case the reader will use the new node.
+    max_height_.store(height, std::memory_order_relaxed);
+  }
+
+  for (int i = 0; i < height; i++) {
+    // NoBarrier_SetNext() suffices since we will add a barrier when
+    // we publish a pointer to "x" in prev[i].
+    x->NoBarrier_SetNext(i, prev_[i]->NoBarrier_Next(i));
+    prev_[i]->SetNext(i, x);
+  }
+  prev_[0] = x;
+  prev_height_.store(height, std::memory_order_relaxed);
+}
+
+template <class Comparator>
+void InlineSkipList<Comparator>::FindLevelSplice(const char* key, Node* before,
+                                                 Node* after, int level,
+                                                 Node** out_prev,
+                                                 Node** out_next) {
+  while (true) {
+    Node* next = before->Next(level);
+    assert(before == head_ || next == nullptr ||
+           KeyIsAfterNode(next->Key(), before));
+    assert(before == head_ || KeyIsAfterNode(key, before));
+    if (next == after || !KeyIsAfterNode(key, next)) {
+      // found it
+      *out_prev = before;
+      *out_next = next;
+      return;
+    }
+    before = next;
+  }
+}
+
+template <class Comparator>
+void InlineSkipList<Comparator>::InsertConcurrently(const char* key) {
+  Node* x = reinterpret_cast<Node*>(const_cast<char*>(key)) - 1;
+  int height = x->UnstashHeight();
+  assert(height >= 1 && height <= kMaxHeight_);
+
+  // We don't have a lock-free algorithm for updating prev_, but we do have
+  // the option of invalidating the entire sequential-insertion cache.
+  // prev_'s invariant is that prev_[i] (i > 0) is the predecessor of
+  // prev_[0] at that level.  We're only going to violate that if height
+  // > 1 and key lands after prev_[height - 1] but before prev_[0].
+  // Comparisons are pretty expensive, so an easier version is to just
+  // clear the cache if height > 1.  We only write to prev_height_ if the
+  // nobody else has, to avoid invalidating the root of the skip list in
+  // all of the other CPU caches.
+  if (height > 1 && prev_height_.load(std::memory_order_relaxed) != 0) {
+    prev_height_.store(0, std::memory_order_relaxed);
+  }
+
+  int max_height = max_height_.load(std::memory_order_relaxed);
+  while (height > max_height) {
+    if (max_height_.compare_exchange_strong(max_height, height)) {
+      // successfully updated it
+      max_height = height;
+      break;
+    }
+    // else retry, possibly exiting the loop because somebody else
+    // increased it
+  }
+  assert(max_height <= kMaxPossibleHeight);
+
+  Node* prev[kMaxPossibleHeight + 1];
+  Node* next[kMaxPossibleHeight + 1];
+  prev[max_height] = head_;
+  next[max_height] = nullptr;
+  for (int i = max_height - 1; i >= 0; --i) {
+    FindLevelSplice(key, prev[i + 1], next[i + 1], i, &prev[i], &next[i]);
+  }
+  for (int i = 0; i < height; ++i) {
+    while (true) {
+      x->NoBarrier_SetNext(i, next[i]);
+      if (prev[i]->CASNext(i, next[i], x)) {
+        // success
+        break;
+      }
+      // CAS failed, we need to recompute prev and next. It is unlikely
+      // to be helpful to try to use a different level as we redo the
+      // search, because it should be unlikely that lots of nodes have
+      // been inserted between prev[i] and next[i]. No point in using
+      // next[i] as the after hint, because we know it is stale.
+      FindLevelSplice(key, prev[i], nullptr, i, &prev[i], &next[i]);
+    }
+  }
+}
+
+template <class Comparator>
+bool InlineSkipList<Comparator>::Contains(const char* key) const {
+  Node* x = FindGreaterOrEqual(key);
+  if (x != nullptr && Equal(key, x->Key())) {
+    return true;
+  } else {
+    return false;
+  }
+}
+
+}  // namespace rocksdb
@@ -0,0 +1,475 @@
+//  Copyright (c) 2013, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under the BSD-style license found in the
+//  LICENSE file in the root directory of this source tree. An additional grant
+//  of patent rights can be found in the PATENTS file in the same directory.
+//
+// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file. See the AUTHORS file for names of contributors.
+
+#include "db/inlineskiplist.h"
+#include <set>
+#include "rocksdb/env.h"
+#include "util/concurrent_arena.h"
+#include "util/hash.h"
+#include "util/random.h"
+#include "util/testharness.h"
+
+namespace rocksdb {
+
+// Our test skip list stores 8-byte unsigned integers
+typedef uint64_t Key;
+
+static const char* Encode(const uint64_t* key) {
+  return reinterpret_cast<const char*>(key);
+}
+
+static Key Decode(const char* key) {
+  Key rv;
+  memcpy(&rv, key, sizeof(Key));
+  return rv;
+}
+
+struct TestComparator {
+  int operator()(const char* a, const char* b) const {
+    if (Decode(a) < Decode(b)) {
+      return -1;
+    } else if (Decode(a) > Decode(b)) {
+      return +1;
+    } else {
+      return 0;
+    }
+  }
+};
+
+class InlineSkipTest : public testing::Test {};
+
+TEST_F(InlineSkipTest, Empty) {
+  Arena arena;
+  TestComparator cmp;
+  InlineSkipList<TestComparator> list(cmp, &arena);
+  Key key = 10;
+  ASSERT_TRUE(!list.Contains(Encode(&key)));
+
+  InlineSkipList<TestComparator>::Iterator iter(&list);
+  ASSERT_TRUE(!iter.Valid());
+  iter.SeekToFirst();
+  ASSERT_TRUE(!iter.Valid());
+  key = 100;
+  iter.Seek(Encode(&key));
+  ASSERT_TRUE(!iter.Valid());
+  iter.SeekToLast();
+  ASSERT_TRUE(!iter.Valid());
+}
+
+TEST_F(InlineSkipTest, InsertAndLookup) {
+  const int N = 2000;
+  const int R = 5000;
+  Random rnd(1000);
+  std::set<Key> keys;
+  ConcurrentArena arena;
+  TestComparator cmp;
+  InlineSkipList<TestComparator> list(cmp, &arena);
+  for (int i = 0; i < N; i++) {
+    Key key = rnd.Next() % R;
+    if (keys.insert(key).second) {
+      char* buf = list.AllocateKey(sizeof(Key));
+      memcpy(buf, &key, sizeof(Key));
+      list.Insert(buf);
+    }
+  }
+
+  for (Key i = 0; i < R; i++) {
+    if (list.Contains(Encode(&i))) {
+      ASSERT_EQ(keys.count(i), 1U);
+    } else {
+      ASSERT_EQ(keys.count(i), 0U);
+    }
+  }
+
+  // Simple iterator tests
+  {
+    InlineSkipList<TestComparator>::Iterator iter(&list);
+    ASSERT_TRUE(!iter.Valid());
+
+    uint64_t zero = 0;
+    iter.Seek(Encode(&zero));
+    ASSERT_TRUE(iter.Valid());
+    ASSERT_EQ(*(keys.begin()), Decode(iter.key()));
+
+    iter.SeekToFirst();
+    ASSERT_TRUE(iter.Valid());
+    ASSERT_EQ(*(keys.begin()), Decode(iter.key()));
+
+    iter.SeekToLast();
+    ASSERT_TRUE(iter.Valid());
+    ASSERT_EQ(*(keys.rbegin()), Decode(iter.key()));
+  }
+
+  // Forward iteration test
+  for (Key i = 0; i < R; i++) {
+    InlineSkipList<TestComparator>::Iterator iter(&list);
+    iter.Seek(Encode(&i));
+
+    // Compare against model iterator
+    std::set<Key>::iterator model_iter = keys.lower_bound(i);
+    for (int j = 0; j < 3; j++) {
+      if (model_iter == keys.end()) {
+        ASSERT_TRUE(!iter.Valid());
+        break;
+      } else {
+        ASSERT_TRUE(iter.Valid());
+        ASSERT_EQ(*model_iter, Decode(iter.key()));
+        ++model_iter;
+        iter.Next();
+      }
+    }
+  }
+
+  // Backward iteration test
+  {
+    InlineSkipList<TestComparator>::Iterator iter(&list);
+    iter.SeekToLast();
+
+    // Compare against model iterator
+    for (std::set<Key>::reverse_iterator model_iter = keys.rbegin();
+         model_iter != keys.rend(); ++model_iter) {
+      ASSERT_TRUE(iter.Valid());
+      ASSERT_EQ(*model_iter, Decode(iter.key()));
+      iter.Prev();
+    }
+    ASSERT_TRUE(!iter.Valid());
+  }
+}
+
+// We want to make sure that with a single writer and multiple
+// concurrent readers (with no synchronization other than when a
+// reader's iterator is created), the reader always observes all the
+// data that was present in the skip list when the iterator was
+// constructor.  Because insertions are happening concurrently, we may
+// also observe new values that were inserted since the iterator was
+// constructed, but we should never miss any values that were present
+// at iterator construction time.
+//
+// We generate multi-part keys:
+//     <key,gen,hash>
+// where:
+//     key is in range [0..K-1]
+//     gen is a generation number for key
+//     hash is hash(key,gen)
+//
+// The insertion code picks a random key, sets gen to be 1 + the last
+// generation number inserted for that key, and sets hash to Hash(key,gen).
+//
+// At the beginning of a read, we snapshot the last inserted
+// generation number for each key.  We then iterate, including random
+// calls to Next() and Seek().  For every key we encounter, we
+// check that it is either expected given the initial snapshot or has
+// been concurrently added since the iterator started.
+class ConcurrentTest {
+ public:
+  static const uint32_t K = 8;
+
+ private:
+  static uint64_t key(Key key) { return (key >> 40); }
+  static uint64_t gen(Key key) { return (key >> 8) & 0xffffffffu; }
+  static uint64_t hash(Key key) { return key & 0xff; }
+
+  static uint64_t HashNumbers(uint64_t k, uint64_t g) {
+    uint64_t data[2] = {k, g};
+    return Hash(reinterpret_cast<char*>(data), sizeof(data), 0);
+  }
+
+  static Key MakeKey(uint64_t k, uint64_t g) {
+    assert(sizeof(Key) == sizeof(uint64_t));
+    assert(k <= K);  // We sometimes pass K to seek to the end of the skiplist
+    assert(g <= 0xffffffffu);
+    return ((k << 40) | (g << 8) | (HashNumbers(k, g) & 0xff));
+  }
+
+  static bool IsValidKey(Key k) {
+    return hash(k) == (HashNumbers(key(k), gen(k)) & 0xff);
+  }
+
+  static Key RandomTarget(Random* rnd) {
+    switch (rnd->Next() % 10) {
+      case 0:
+        // Seek to beginning
+        return MakeKey(0, 0);
+      case 1:
+        // Seek to end
+        return MakeKey(K, 0);
+      default:
+        // Seek to middle
+        return MakeKey(rnd->Next() % K, 0);
+    }
+  }
+
+  // Per-key generation
+  struct State {
+    std::atomic<int> generation[K];
+    void Set(int k, int v) {
+      generation[k].store(v, std::memory_order_release);
+    }
+    int Get(int k) { return generation[k].load(std::memory_order_acquire); }
+
+    State() {
+      for (unsigned int k = 0; k < K; k++) {
+        Set(k, 0);
+      }
+    }
+  };
+
+  // Current state of the test
+  State current_;
+
+  ConcurrentArena arena_;
+
+  // InlineSkipList is not protected by mu_.  We just use a single writer
+  // thread to modify it.
+  InlineSkipList<TestComparator> list_;
+
+ public:
+  ConcurrentTest() : list_(TestComparator(), &arena_) {}
+
+  // REQUIRES: No concurrent calls to WriteStep or ConcurrentWriteStep
+  void WriteStep(Random* rnd) {
+    const uint32_t k = rnd->Next() % K;
+    const int g = current_.Get(k) + 1;
+    const Key new_key = MakeKey(k, g);
+    char* buf = list_.AllocateKey(sizeof(Key));
+    memcpy(buf, &new_key, sizeof(Key));
+    list_.Insert(buf);
+    current_.Set(k, g);
+  }
+
+  // REQUIRES: No concurrent calls for the same k
+  void ConcurrentWriteStep(uint32_t k) {
+    const int g = current_.Get(k) + 1;
+    const Key new_key = MakeKey(k, g);
+    char* buf = list_.AllocateKey(sizeof(Key));
+    memcpy(buf, &new_key, sizeof(Key));
+    list_.InsertConcurrently(buf);
+    ASSERT_EQ(g, current_.Get(k) + 1);
+    current_.Set(k, g);
+  }
+
+  void ReadStep(Random* rnd) {
+    // Remember the initial committed state of the skiplist.
+    State initial_state;
+    for (unsigned int k = 0; k < K; k++) {
+      initial_state.Set(k, current_.Get(k));
+    }
+
+    Key pos = RandomTarget(rnd);
+    InlineSkipList<TestComparator>::Iterator iter(&list_);
+    iter.Seek(Encode(&pos));
+    while (true) {
+      Key current;
+      if (!iter.Valid()) {
+        current = MakeKey(K, 0);
+      } else {
+        current = Decode(iter.key());
+        ASSERT_TRUE(IsValidKey(current)) << current;
+      }
+      ASSERT_LE(pos, current) << "should not go backwards";
+
+      // Verify that everything in [pos,current) was not present in
+      // initial_state.
+      while (pos < current) {
+        ASSERT_LT(key(pos), K) << pos;
+
+        // Note that generation 0 is never inserted, so it is ok if
+        // <*,0,*> is missing.
+        ASSERT_TRUE((gen(pos) == 0U) ||
+                    (gen(pos) > static_cast<uint64_t>(initial_state.Get(
+                                    static_cast<int>(key(pos))))))
+            << "key: " << key(pos) << "; gen: " << gen(pos)
+            << "; initgen: " << initial_state.Get(static_cast<int>(key(pos)));
+
+        // Advance to next key in the valid key space
+        if (key(pos) < key(current)) {
+          pos = MakeKey(key(pos) + 1, 0);
+        } else {
+          pos = MakeKey(key(pos), gen(pos) + 1);
+        }
+      }
+
+      if (!iter.Valid()) {
+        break;
+      }
+
+      if (rnd->Next() % 2) {
+        iter.Next();
+        pos = MakeKey(key(pos), gen(pos) + 1);
+      } else {
+        Key new_target = RandomTarget(rnd);
+        if (new_target > pos) {
+          pos = new_target;
+          iter.Seek(Encode(&new_target));
+        }
+      }
+    }
+  }
+};
+const uint32_t ConcurrentTest::K;
+
+// Simple test that does single-threaded testing of the ConcurrentTest
+// scaffolding.
+TEST_F(InlineSkipTest, ConcurrentReadWithoutThreads) {
+  ConcurrentTest test;
+  Random rnd(test::RandomSeed());
+  for (int i = 0; i < 10000; i++) {
+    test.ReadStep(&rnd);
+    test.WriteStep(&rnd);
+  }
+}
+
+TEST_F(InlineSkipTest, ConcurrentInsertWithoutThreads) {
+  ConcurrentTest test;
+  Random rnd(test::RandomSeed());
+  for (int i = 0; i < 10000; i++) {
+    test.ReadStep(&rnd);
+    uint32_t base = rnd.Next();
+    for (int j = 0; j < 4; ++j) {
+      test.ConcurrentWriteStep((base + j) % ConcurrentTest::K);
+    }
+  }
+}
+
+class TestState {
+ public:
+  ConcurrentTest t_;
+  int seed_;
+  std::atomic<bool> quit_flag_;
+  std::atomic<uint32_t> next_writer_;
+
+  enum ReaderState { STARTING, RUNNING, DONE };
+
+  explicit TestState(int s)
+      : seed_(s),
+        quit_flag_(false),
+        state_(STARTING),
+        pending_writers_(0),
+        state_cv_(&mu_) {}
+
+  void Wait(ReaderState s) {
+    mu_.Lock();
+    while (state_ != s) {
+      state_cv_.Wait();
+    }
+    mu_.Unlock();
+  }
+
+  void Change(ReaderState s) {
+    mu_.Lock();
+    state_ = s;
+    state_cv_.Signal();
+    mu_.Unlock();
+  }
+
+  void AdjustPendingWriters(int delta) {
+    mu_.Lock();
+    pending_writers_ += delta;
+    if (pending_writers_ == 0) {
+      state_cv_.Signal();
+    }
+    mu_.Unlock();
+  }
+
+  void WaitForPendingWriters() {
+    mu_.Lock();
+    while (pending_writers_ != 0) {
+      state_cv_.Wait();
+    }
+    mu_.Unlock();
+  }
+
+ private:
+  port::Mutex mu_;
+  ReaderState state_;
+  int pending_writers_;
+  port::CondVar state_cv_;
+};
+
+static void ConcurrentReader(void* arg) {
+  TestState* state = reinterpret_cast<TestState*>(arg);
+  Random rnd(state->seed_);
+  int64_t reads = 0;
+  state->Change(TestState::RUNNING);
+  while (!state->quit_flag_.load(std::memory_order_acquire)) {
+    state->t_.ReadStep(&rnd);
+    ++reads;
+  }
+  state->Change(TestState::DONE);
+}
+
+static void ConcurrentWriter(void* arg) {
+  TestState* state = reinterpret_cast<TestState*>(arg);
+  uint32_t k = state->next_writer_++ % ConcurrentTest::K;
+  state->t_.ConcurrentWriteStep(k);
+  state->AdjustPendingWriters(-1);
+}
+
+static void RunConcurrentRead(int run) {
+  const int seed = test::RandomSeed() + (run * 100);
+  Random rnd(seed);
+  const int N = 1000;
+  const int kSize = 1000;
+  for (int i = 0; i < N; i++) {
+    if ((i % 100) == 0) {
+      fprintf(stderr, "Run %d of %d\n", i, N);
+    }
+    TestState state(seed + 1);
+    Env::Default()->Schedule(ConcurrentReader, &state);
+    state.Wait(TestState::RUNNING);
+    for (int k = 0; k < kSize; ++k) {
+      state.t_.WriteStep(&rnd);
+    }
+    state.quit_flag_.store(true, std::memory_order_release);
+    state.Wait(TestState::DONE);
+  }
+}
+
+static void RunConcurrentInsert(int run, int write_parallelism = 4) {
+  Env::Default()->SetBackgroundThreads(1 + write_parallelism,
+                                       Env::Priority::LOW);
+  const int seed = test::RandomSeed() + (run * 100);
+  Random rnd(seed);
+  const int N = 1000;
+  const int kSize = 1000;
+  for (int i = 0; i < N; i++) {
+    if ((i % 100) == 0) {
+      fprintf(stderr, "Run %d of %d\n", i, N);
+    }
+    TestState state(seed + 1);
+    Env::Default()->Schedule(ConcurrentReader, &state);
+    state.Wait(TestState::RUNNING);
+    for (int k = 0; k < kSize; k += write_parallelism) {
+      state.next_writer_ = rnd.Next();
+      state.AdjustPendingWriters(write_parallelism);
+      for (int p = 0; p < write_parallelism; ++p) {
+        Env::Default()->Schedule(ConcurrentWriter, &state);
+      }
+      state.WaitForPendingWriters();
+    }
+    state.quit_flag_.store(true, std::memory_order_release);
+    state.Wait(TestState::DONE);
+  }
+}
+
+TEST_F(InlineSkipTest, ConcurrentRead1) { RunConcurrentRead(1); }
+TEST_F(InlineSkipTest, ConcurrentRead2) { RunConcurrentRead(2); }
+TEST_F(InlineSkipTest, ConcurrentRead3) { RunConcurrentRead(3); }
+TEST_F(InlineSkipTest, ConcurrentRead4) { RunConcurrentRead(4); }
+TEST_F(InlineSkipTest, ConcurrentRead5) { RunConcurrentRead(5); }
+TEST_F(InlineSkipTest, ConcurrentInsert1) { RunConcurrentInsert(1); }
+TEST_F(InlineSkipTest, ConcurrentInsert2) { RunConcurrentInsert(2); }
+TEST_F(InlineSkipTest, ConcurrentInsert3) { RunConcurrentInsert(3); }
+
+}  // namespace rocksdb
+
+int main(int argc, char** argv) {
+  ::testing::InitGoogleTest(&argc, argv);
+  return RUN_ALL_TESTS();
+}
@@ -35,8 +35,7 @@ void PrintLevelStatsHeader(char* buf, size_t len, const std::string& cf_name) {
      "\n** Compaction Stats [%s] **\n"
      "Level    Files   Size(MB) Score Read(GB)  Rn(GB) Rnp1(GB) "
      "Write(GB) Wnew(GB) Moved(GB) W-Amp Rd(MB/s) Wr(MB/s) "
-      "Comp(sec) Comp(cnt) Avg(sec) "
-      "Stall(cnt)  KeyIn KeyDrop\n"
+      "Comp(sec) Comp(cnt) Avg(sec) KeyIn KeyDrop\n"
      "--------------------------------------------------------------------"
      "-----------------------------------------------------------"
      "--------------------------------------\n",
@@ -44,9 +43,9 @@ void PrintLevelStatsHeader(char* buf, size_t len, const std::string& cf_name) {
 }

 void PrintLevelStats(char* buf, size_t len, const std::string& name,
-    int num_files, int being_compacted, double total_file_size, double score,
-    double w_amp, uint64_t stalls,
-    const InternalStats::CompactionStats& stats) {
+  int num_files, int being_compacted, double total_file_size,
+  double score, double w_amp,
+  const InternalStats::CompactionStats& stats) {
  uint64_t bytes_read =
      stats.bytes_read_non_output_levels + stats.bytes_read_output_level;
  int64_t bytes_new =
@@ -70,8 +69,6 @@ void PrintLevelStats(char* buf, size_t len, const std::string& name,
           "%9.0f "                    /* Comp(sec) */
           "%9d "                      /* Comp(cnt) */
           "%8.3f "                    /* Avg(sec) */
-           "%10" PRIu64
-           " "      /* Stall(cnt) */
           "%7s "   /* KeyIn */
           "%6s\n", /* KeyDrop */
           name.c_str(),
@@ -82,7 +79,7 @@ void PrintLevelStats(char* buf, size_t len, const std::string& name,
           bytes_read / kMB / elapsed, stats.bytes_written / kMB / elapsed,
           stats.micros / kMicrosInSec, stats.count,
           stats.count == 0 ? 0 : stats.micros / kMicrosInSec / stats.count,
-           stalls, num_input_records.c_str(), num_dropped_records.c_str());
+           num_input_records.c_str(), num_dropped_records.c_str());
 }
 }

@@ -130,6 +127,8 @@ static const std::string aggregated_table_properties =
    "aggregated-table-properties";
 static const std::string aggregated_table_properties_at_level =
    aggregated_table_properties + "-at-level";
+static const std::string num_running_compactions = "num-running-compactions";
+static const std::string num_running_flushes = "num-running-flushes";

 const std::string DB::Properties::kNumFilesAtLevelPrefix =
                      rocksdb_prefix + num_files_at_level_prefix;
@@ -143,6 +142,10 @@ const std::string DB::Properties::kMemTableFlushPending =
                      rocksdb_prefix + mem_table_flush_pending;
 const std::string DB::Properties::kCompactionPending =
                      rocksdb_prefix + compaction_pending;
+const std::string DB::Properties::kNumRunningCompactions =
+    rocksdb_prefix + num_running_compactions;
+const std::string DB::Properties::kNumRunningFlushes =
+    rocksdb_prefix + num_running_flushes;
 const std::string DB::Properties::kBackgroundErrors =
                      rocksdb_prefix + background_errors;
 const std::string DB::Properties::kCurSizeActiveMemTable =
@@ -260,6 +263,10 @@ DBPropertyType GetPropertyType(const Slice& property, bool* is_int_property,
    return kTotalSstFilesSize;
  } else if (in == estimate_pending_comp_bytes) {
    return kEstimatePendingCompactionBytes;
+  } else if (in == num_running_flushes) {
+    return kNumRunningFlushes;
+  } else if (in == num_running_compactions) {
+    return kNumRunningCompactions;
  }
  return kUnknown;
 }
@@ -388,11 +395,17 @@ bool InternalStats::GetIntProperty(DBPropertyType property_type,
      // Return number of mem tables that are ready to flush (made immutable)
      *value = (cfd_->imm()->IsFlushPending() ? 1 : 0);
      return true;
+    case kNumRunningFlushes:
+      *value = db->num_running_flushes();
+      return true;
    case kCompactionPending:
      // 1 if the system already determines at least one compaction is needed.
      // 0 otherwise,
      *value = (cfd_->compaction_picker()->NeedsCompaction(vstorage) ? 1 : 0);
      return true;
+    case kNumRunningCompactions:
+      *value = db->num_running_compactions_;
+      return true;
    case kBackgroundErrors:
      // Accumulated number of  errors in background flushes or compactions.
      *value = GetBackgroundErrorCount();
@@ -472,14 +485,14 @@ void InternalStats::DumpDBStats(std::string* value) {
           seconds_up, interval_seconds_up);
  value->append(buf);
  // Cumulative
-  uint64_t user_bytes_written = db_stats_[InternalStats::BYTES_WRITTEN];
-  uint64_t num_keys_written = db_stats_[InternalStats::NUMBER_KEYS_WRITTEN];
-  uint64_t write_other = db_stats_[InternalStats::WRITE_DONE_BY_OTHER];
-  uint64_t write_self = db_stats_[InternalStats::WRITE_DONE_BY_SELF];
-  uint64_t wal_bytes = db_stats_[InternalStats::WAL_FILE_BYTES];
-  uint64_t wal_synced = db_stats_[InternalStats::WAL_FILE_SYNCED];
-  uint64_t write_with_wal = db_stats_[InternalStats::WRITE_WITH_WAL];
-  uint64_t write_stall_micros = db_stats_[InternalStats::WRITE_STALL_MICROS];
+  uint64_t user_bytes_written = GetDBStats(InternalStats::BYTES_WRITTEN);
+  uint64_t num_keys_written = GetDBStats(InternalStats::NUMBER_KEYS_WRITTEN);
+  uint64_t write_other = GetDBStats(InternalStats::WRITE_DONE_BY_OTHER);
+  uint64_t write_self = GetDBStats(InternalStats::WRITE_DONE_BY_SELF);
+  uint64_t wal_bytes = GetDBStats(InternalStats::WAL_FILE_BYTES);
+  uint64_t wal_synced = GetDBStats(InternalStats::WAL_FILE_SYNCED);
+  uint64_t write_with_wal = GetDBStats(InternalStats::WRITE_WITH_WAL);
+  uint64_t write_stall_micros = GetDBStats(InternalStats::WRITE_STALL_MICROS);
  uint64_t compact_bytes_read = 0;
  uint64_t compact_bytes_write = 0;
  uint64_t compact_micros = 0;
@@ -661,45 +674,38 @@ void InternalStats::DumpCFStats(std::string* value) {
  int total_files = 0;
  int total_files_being_compacted = 0;
  double total_file_size = 0;
-  uint64_t total_slowdown_count_soft = 0;
-  uint64_t total_slowdown_count_hard = 0;
-  uint64_t total_stall_count = 0;
  for (int level = 0; level < number_levels_; level++) {
    int files = vstorage->NumLevelFiles(level);
    total_files += files;
    total_files_being_compacted += files_being_compacted[level];
    if (comp_stats_[level].micros > 0 || files > 0) {
-      uint64_t stalls =
-          level == 0 ? (cf_stats_count_[LEVEL0_SLOWDOWN_TOTAL] +
-                        cf_stats_count_[LEVEL0_NUM_FILES_TOTAL] +
-                        cf_stats_count_[HARD_PENDING_COMPACTION_BYTES_LIMIT] +
-                        cf_stats_count_[MEMTABLE_COMPACTION])
-                     : (stall_leveln_slowdown_count_soft_[level] +
-                        stall_leveln_slowdown_count_hard_[level]);
-
      stats_sum.Add(comp_stats_[level]);
      total_file_size += vstorage->NumLevelBytes(level);
-      total_stall_count += stalls;
-      total_slowdown_count_soft += stall_leveln_slowdown_count_soft_[level];
-      total_slowdown_count_hard += stall_leveln_slowdown_count_hard_[level];
      double w_amp =
          (comp_stats_[level].bytes_read_non_output_levels == 0) ? 0.0
          : static_cast<double>(comp_stats_[level].bytes_written) /
            comp_stats_[level].bytes_read_non_output_levels;
      PrintLevelStats(buf, sizeof(buf), "L" + ToString(level), files,
                      files_being_compacted[level],
-                      vstorage->NumLevelBytes(level), compaction_score[level],
-                      w_amp, stalls, comp_stats_[level]);
+                      static_cast<double>(vstorage->NumLevelBytes(level)),
+                      compaction_score[level],
+                      w_amp, comp_stats_[level]);
      value->append(buf);
    }
  }
  uint64_t curr_ingest = cf_stats_value_[BYTES_FLUSHED];
  // Cumulative summary
  double w_amp = stats_sum.bytes_written / static_cast<double>(curr_ingest + 1);
+  uint64_t total_stall_count =
+      cf_stats_count_[LEVEL0_SLOWDOWN_TOTAL] +
+      cf_stats_count_[LEVEL0_NUM_FILES_TOTAL] +
+      cf_stats_count_[SOFT_PENDING_COMPACTION_BYTES_LIMIT] +
+      cf_stats_count_[HARD_PENDING_COMPACTION_BYTES_LIMIT] +
+      cf_stats_count_[MEMTABLE_COMPACTION] + cf_stats_count_[MEMTABLE_SLOWDOWN];
  // Stats summary across levels
  PrintLevelStats(buf, sizeof(buf), "Sum", total_files,
-      total_files_being_compacted, total_file_size, 0, w_amp,
-      total_stall_count, stats_sum);
+                  total_files_being_compacted, total_file_size, 0, w_amp,
+                  stats_sum);
  value->append(buf);
  // Interval summary
  uint64_t interval_ingest =
@@ -707,9 +713,7 @@ void InternalStats::DumpCFStats(std::string* value) {
  CompactionStats interval_stats(stats_sum);
  interval_stats.Subtract(cf_stats_snapshot_.comp_stats);
  w_amp = interval_stats.bytes_written / static_cast<double>(interval_ingest);
-  PrintLevelStats(buf, sizeof(buf), "Int", 0, 0, 0, 0,
-      w_amp, total_stall_count - cf_stats_snapshot_.stall_count,
-      interval_stats);
+  PrintLevelStats(buf, sizeof(buf), "Int", 0, 0, 0, 0, w_amp, interval_stats);
  value->append(buf);

  snprintf(buf, sizeof(buf),
@@ -726,19 +730,23 @@ void InternalStats::DumpCFStats(std::string* value) {
                             "%" PRIu64
                             " level0_numfiles_with_compaction, "
                             "%" PRIu64
-                             " pending_compaction_bytes, "
+                             " stop for pending_compaction_bytes, "
+                             "%" PRIu64
+                             " slowdown for pending_compaction_bytes, "
                             "%" PRIu64
                             " memtable_compaction, "
                             "%" PRIu64
-                             " leveln_slowdown_soft, "
-                             "%" PRIu64 " leveln_slowdown_hard\n",
+                             " memtable_slowdown, "
+                             "interval %" PRIu64 " total count\n",
           cf_stats_count_[LEVEL0_SLOWDOWN_TOTAL],
           cf_stats_count_[LEVEL0_SLOWDOWN_WITH_COMPACTION],
           cf_stats_count_[LEVEL0_NUM_FILES_TOTAL],
           cf_stats_count_[LEVEL0_NUM_FILES_WITH_COMPACTION],
           cf_stats_count_[HARD_PENDING_COMPACTION_BYTES_LIMIT],
-           cf_stats_count_[MEMTABLE_COMPACTION], total_slowdown_count_soft,
-           total_slowdown_count_hard);
+           cf_stats_count_[SOFT_PENDING_COMPACTION_BYTES_LIMIT],
+           cf_stats_count_[MEMTABLE_COMPACTION],
+           cf_stats_count_[MEMTABLE_SLOWDOWN],
+           total_stall_count - cf_stats_snapshot_.stall_count);
  value->append(buf);

  cf_stats_snapshot_.ingest_bytes = curr_ingest;
@@ -38,7 +38,10 @@ enum DBPropertyType : uint32_t {
                                 // in memory that have already been flushed
  kMemtableFlushPending,         // Return 1 if mem table flushing is pending,
                                 // otherwise 0.
+  kNumRunningFlushes,      // Return the number of currently running flushes.
  kCompactionPending,      // Return 1 if a compaction is pending. Otherwise 0.
+  kNumRunningCompactions,  // Return the number of currently running
+                           // compactions.
  kBackgroundErrors,       // Return accumulated background errors encountered.
  kCurSizeActiveMemTable,  // Return current size of the active memtable
  kCurSizeAllMemTables,    // Return current size of unflushed
@@ -49,10 +52,10 @@ enum DBPropertyType : uint32_t {
                                   // memtable.
  kNumEntriesInImmutableMemtable,  // Return sum of number of entries in all
                                   // the immutable mem tables.
-  kNumDeletesInMutableMemtable,    // Return number of entries in the mutable
-                                   // memtable.
-  kNumDeletesInImmutableMemtable,  // Return sum of number of deletes in all
-                                   // the immutable mem tables.
+  kNumDeletesInMutableMemtable,    // Return number of deletion entries in the
+                                   // mutable memtable.
+  kNumDeletesInImmutableMemtable,  // Return the total number of deletion
+                                   // entries in all the immutable mem tables.
  kEstimatedNumKeys,  // Estimated total number of keys in the database.
  kEstimatedUsageByTableReaders,  // Estimated memory by table readers.
  kIsFileDeletionEnabled,         // Equals disable_delete_obsolete_files_,
@@ -83,8 +86,10 @@ class InternalStats {
    LEVEL0_SLOWDOWN_TOTAL,
    LEVEL0_SLOWDOWN_WITH_COMPACTION,
    MEMTABLE_COMPACTION,
+    MEMTABLE_SLOWDOWN,
    LEVEL0_NUM_FILES_TOTAL,
    LEVEL0_NUM_FILES_WITH_COMPACTION,
+    SOFT_PENDING_COMPACTION_BYTES_LIMIT,
    HARD_PENDING_COMPACTION_BYTES_LIMIT,
    WRITE_STALLS_ENUM_MAX,
    BYTES_FLUSHED,
@@ -104,30 +109,16 @@ class InternalStats {
  };

  InternalStats(int num_levels, Env* env, ColumnFamilyData* cfd)
-      : db_stats_(INTERNAL_DB_STATS_ENUM_MAX),
-        cf_stats_value_(INTERNAL_CF_STATS_ENUM_MAX),
-        cf_stats_count_(INTERNAL_CF_STATS_ENUM_MAX),
+      : db_stats_{},
+        cf_stats_value_{},
+        cf_stats_count_{},
        comp_stats_(num_levels),
-        stall_leveln_slowdown_count_hard_(num_levels),
-        stall_leveln_slowdown_count_soft_(num_levels),
        file_read_latency_(num_levels),
        bg_error_count_(0),
        number_levels_(num_levels),
        env_(env),
        cfd_(cfd),
-        started_at_(env->NowMicros()) {
-    for (int i = 0; i< INTERNAL_DB_STATS_ENUM_MAX; ++i) {
-      db_stats_[i] = 0;
-    }
-    for (int i = 0; i< INTERNAL_CF_STATS_ENUM_MAX; ++i) {
-      cf_stats_value_[i] = 0;
-      cf_stats_count_[i] = 0;
-    }
-    for (int i = 0; i < num_levels; ++i) {
-      stall_leveln_slowdown_count_hard_[i] = 0;
-      stall_leveln_slowdown_count_soft_[i] = 0;
-    }
-  }
+        started_at_(env->NowMicros()) {}

  // Per level compaction stats.  comp_stats_[level] stores the stats for
  // compactions that produced data for the specified "level".
@@ -234,21 +225,19 @@ class InternalStats {
    comp_stats_[level].bytes_moved += amount;
  }

-  void RecordLevelNSlowdown(int level, bool soft) {
-    if (soft) {
-      ++stall_leveln_slowdown_count_soft_[level];
-    } else {
-      ++stall_leveln_slowdown_count_hard_[level];
-    }
-  }
-
  void AddCFStats(InternalCFStatsType type, uint64_t value) {
    cf_stats_value_[type] += value;
    ++cf_stats_count_[type];
  }

  void AddDBStats(InternalDBStatsType type, uint64_t value) {
-    db_stats_[type] += value;
+    auto& v = db_stats_[type];
+    v.store(v.load(std::memory_order_relaxed) + value,
+            std::memory_order_relaxed);
+  }
+
+  uint64_t GetDBStats(InternalDBStatsType type) {
+    return db_stats_[type].load(std::memory_order_relaxed);
  }

  HistogramImpl* GetFileReadHist(int level) {
@@ -273,15 +262,12 @@ class InternalStats {
  void DumpCFStats(std::string* value);

  // Per-DB stats
-  std::vector<uint64_t> db_stats_;
+  std::atomic<uint64_t> db_stats_[INTERNAL_DB_STATS_ENUM_MAX];
  // Per-ColumnFamily stats
-  std::vector<uint64_t> cf_stats_value_;
-  std::vector<uint64_t> cf_stats_count_;
+  uint64_t cf_stats_value_[INTERNAL_CF_STATS_ENUM_MAX];
+  uint64_t cf_stats_count_[INTERNAL_CF_STATS_ENUM_MAX];
  // Per-ColumnFamily/level compaction stats
  std::vector<CompactionStats> comp_stats_;
-  // These count the number of microseconds for which MakeRoomForWrite stalls.
-  std::vector<uint64_t> stall_leveln_slowdown_count_hard_;
-  std::vector<uint64_t> stall_leveln_slowdown_count_soft_;
  std::vector<HistogramImpl> file_read_latency_;

  // Used to compute per-interval statistics
@@ -356,8 +342,10 @@ class InternalStats {
    LEVEL0_SLOWDOWN_TOTAL,
    LEVEL0_SLOWDOWN_WITH_COMPACTION,
    MEMTABLE_COMPACTION,
+    MEMTABLE_SLOWDOWN,
    LEVEL0_NUM_FILES_TOTAL,
    LEVEL0_NUM_FILES_WITH_COMPACTION,
+    SOFT_PENDING_COMPACTION_BYTES_LIMIT,
    HARD_PENDING_COMPACTION_BYTES_LIMIT,
    WRITE_STALLS_ENUM_MAX,
    BYTES_FLUSHED,
@@ -404,8 +392,6 @@ class InternalStats {

  void IncBytesMoved(int level, uint64_t amount) {}

-  void RecordLevelNSlowdown(int level, bool soft) {}
-
  void AddCFStats(InternalCFStatsType type, uint64_t value) {}

  void AddDBStats(InternalDBStatsType type, uint64_t value) {}
@@ -4,10 +4,12 @@
 //  of patent rights can be found in the PATENTS file in the same directory.

 #include "db/db_impl.h"
+#include "db/db_test_util.h"
 #include "db/dbformat.h"
 #include "db/filename.h"
 #include "db/version_set.h"
 #include "db/write_batch_internal.h"
+#include "memtable/hash_linklist_rep.h"
 #include "rocksdb/cache.h"
 #include "rocksdb/compaction_filter.h"
 #include "rocksdb/db.h"
@@ -22,7 +24,6 @@
 #include "table/block_based_table_factory.h"
 #include "table/plain_table_factory.h"
 #include "util/hash.h"
-#include "util/hash_linklist_rep.h"
 #include "util/logging.h"
 #include "util/mutexlock.h"
 #include "util/rate_limiter.h"
@@ -37,119 +38,45 @@

 namespace rocksdb {

-class EventListenerTest : public testing::Test {
+class EventListenerTest : public DBTestBase {
 public:
-  EventListenerTest() {
-    dbname_ = test::TmpDir() + "/listener_test";
-    EXPECT_OK(DestroyDB(dbname_, Options()));
-    db_ = nullptr;
-    Reopen();
-  }
-
-  ~EventListenerTest() {
-    Close();
-    Options options;
-    options.db_paths.emplace_back(dbname_, 0);
-    options.db_paths.emplace_back(dbname_ + "_2", 0);
-    options.db_paths.emplace_back(dbname_ + "_3", 0);
-    options.db_paths.emplace_back(dbname_ + "_4", 0);
-    EXPECT_OK(DestroyDB(dbname_, options));
-  }
-
-  void CreateColumnFamilies(const std::vector<std::string>& cfs,
-                            const ColumnFamilyOptions* options = nullptr) {
-    ColumnFamilyOptions cf_opts;
-    cf_opts = ColumnFamilyOptions(Options());
-    size_t cfi = handles_.size();
-    handles_.resize(cfi + cfs.size());
-    for (auto cf : cfs) {
-      ASSERT_OK(db_->CreateColumnFamily(cf_opts, cf, &handles_[cfi++]));
-    }
-  }
-
-  void Close() {
-    for (auto h : handles_) {
-      delete h;
-    }
-    handles_.clear();
-    delete db_;
-    db_ = nullptr;
-  }
-
-  void ReopenWithColumnFamilies(const std::vector<std::string>& cfs,
-                                const Options* options = nullptr) {
-    ASSERT_OK(TryReopenWithColumnFamilies(cfs, options));
-  }
-
-  Status TryReopenWithColumnFamilies(const std::vector<std::string>& cfs,
-                                     const Options* options = nullptr) {
-    Close();
-    Options opts = (options == nullptr) ? Options() : *options;
-    std::vector<const Options*> v_opts(cfs.size(), &opts);
-    return TryReopenWithColumnFamilies(cfs, v_opts);
-  }
-
-  Status TryReopenWithColumnFamilies(
-      const std::vector<std::string>& cfs,
-      const std::vector<const Options*>& options) {
-    Close();
-    EXPECT_EQ(cfs.size(), options.size());
-    std::vector<ColumnFamilyDescriptor> column_families;
-    for (size_t i = 0; i < cfs.size(); ++i) {
-      column_families.push_back(ColumnFamilyDescriptor(cfs[i], *options[i]));
-    }
-    DBOptions db_opts = DBOptions(*options[0]);
-    return DB::Open(db_opts, dbname_, column_families, &handles_, &db_);
-  }
-
-  Status TryReopen(Options* options = nullptr) {
-    Close();
-    Options opts;
-    if (options != nullptr) {
-      opts = *options;
-    } else {
-      opts.create_if_missing = true;
-    }
-
-    return DB::Open(opts, dbname_, &db_);
-  }
-
-  void Reopen(Options* options = nullptr) {
-    ASSERT_OK(TryReopen(options));
-  }
-
-  void CreateAndReopenWithCF(const std::vector<std::string>& cfs,
-                             const Options* options = nullptr) {
-    CreateColumnFamilies(cfs, options);
-    std::vector<std::string> cfs_plus_default = cfs;
-    cfs_plus_default.insert(cfs_plus_default.begin(), kDefaultColumnFamilyName);
-    ReopenWithColumnFamilies(cfs_plus_default, options);
-  }
-
-  DBImpl* dbfull() {
-    return reinterpret_cast<DBImpl*>(db_);
-  }
-
-  Status Put(int cf, const Slice& k, const Slice& v,
-             WriteOptions wo = WriteOptions()) {
-    return db_->Put(wo, handles_[cf], k, v);
-  }
-
-  Status Flush(size_t cf = 0) {
-    FlushOptions opt = FlushOptions();
-    opt.wait = true;
-    if (cf == 0) {
-      return db_->Flush(opt);
-    } else {
-      return db_->Flush(opt, handles_[cf]);
-    }
-  }
+  EventListenerTest() : DBTestBase("/listener_test") {}

  const size_t k110KB = 110 << 10;
+};

-  DB* db_;
-  std::string dbname_;
-  std::vector<ColumnFamilyHandle*> handles_;
+struct TestPropertiesCollector : public rocksdb::TablePropertiesCollector {
+  virtual rocksdb::Status AddUserKey(const rocksdb::Slice& key,
+                                     const rocksdb::Slice& value,
+                                     rocksdb::EntryType type,
+                                     rocksdb::SequenceNumber seq,
+                                     uint64_t file_size) override {
+    return Status::OK();
+  }
+  virtual rocksdb::Status Finish(
+      rocksdb::UserCollectedProperties* properties) override {
+    properties->insert({"0", "1"});
+    return Status::OK();
+  }
+
+  virtual const char* Name() const override {
+    return "TestTablePropertiesCollector";
+  }
+
+  rocksdb::UserCollectedProperties GetReadableProperties() const override {
+    rocksdb::UserCollectedProperties ret;
+    ret["2"] = "3";
+    return ret;
+  }
+};
+
+class TestPropertiesCollectorFactory : public TablePropertiesCollectorFactory {
+ public:
+  virtual TablePropertiesCollector* CreateTablePropertiesCollector(
+      TablePropertiesCollectorFactory::Context context) override {
+    return new TestPropertiesCollector;
+  }
+  const char* Name() const override { return "TestTablePropertiesCollector"; }
 };

 class TestCompactionListener : public EventListener {
@@ -161,6 +88,16 @@ class TestCompactionListener : public EventListener {
    ASSERT_GT(ci.output_files.size(), 0U);
    ASSERT_EQ(db->GetEnv()->GetThreadID(), ci.thread_id);
    ASSERT_GT(ci.thread_id, 0U);
+
+    for (auto fl : {ci.input_files, ci.output_files}) {
+      for (auto fn : fl) {
+        auto it = ci.table_properties.find(fn);
+        ASSERT_NE(it, ci.table_properties.end());
+        auto tp = it->second;
+        ASSERT_TRUE(tp != nullptr);
+        ASSERT_EQ(tp->user_collected_properties.find("0")->second, "1");
+      }
+    }
  }

  std::vector<DB*> compacted_dbs_;
@@ -186,13 +123,15 @@ TEST_F(EventListenerTest, OnSingleDBCompactionTest) {
  options.enable_thread_tracking = true;
 #endif  // ROCKSDB_USING_THREAD_STATUS
  options.level0_file_num_compaction_trigger = kNumL0Files;
+  options.table_properties_collector_factories.push_back(
+      std::make_shared<TestPropertiesCollectorFactory>());

  TestCompactionListener* listener = new TestCompactionListener();
  options.listeners.emplace_back(listener);
  std::vector<std::string> cf_names = {
      "pikachu", "ilya", "muromec", "dobrynia",
      "nikitich", "alyosha", "popovich"};
-  CreateAndReopenWithCF(cf_names, &options);
+  CreateAndReopenWithCF(cf_names, options);
  ASSERT_OK(Put(1, "pikachu", std::string(90000, 'p')));
  ASSERT_OK(Put(2, "ilya", std::string(90000, 'i')));
  ASSERT_OK(Put(3, "muromec", std::string(90000, 'm')));
@@ -200,12 +139,12 @@ TEST_F(EventListenerTest, OnSingleDBCompactionTest) {
  ASSERT_OK(Put(5, "nikitich", std::string(90000, 'n')));
  ASSERT_OK(Put(6, "alyosha", std::string(90000, 'a')));
  ASSERT_OK(Put(7, "popovich", std::string(90000, 'p')));
-  for (size_t i = 1; i < 8; ++i) {
+  for (int i = 1; i < 8; ++i) {
    ASSERT_OK(Flush(i));
-    const Slice kStart = "a";
-    const Slice kEnd = "z";
+    const Slice kRangeStart = "a";
+    const Slice kRangeEnd = "z";
    ASSERT_OK(dbfull()->CompactRange(CompactRangeOptions(), handles_[i],
-                                     &kStart, &kEnd));
+                                     &kRangeStart, &kRangeEnd));
    dbfull()->TEST_WaitForFlushMemTable();
    dbfull()->TEST_WaitForCompact();
  }
@@ -274,6 +213,8 @@ class TestFlushListener : public EventListener {
    ASSERT_EQ(prev_fc_info_.file_path, info.file_path);
    ASSERT_EQ(db->GetEnv()->GetThreadID(), info.thread_id);
    ASSERT_GT(info.thread_id, 0U);
+    ASSERT_EQ(info.table_properties.user_collected_properties.find("0")->second,
+              "1");
  }

  std::vector<std::string> flushed_column_family_names_;
@@ -299,7 +240,9 @@ TEST_F(EventListenerTest, OnSingleDBFlushTest) {
  std::vector<std::string> cf_names = {
      "pikachu", "ilya", "muromec", "dobrynia",
      "nikitich", "alyosha", "popovich"};
-  CreateAndReopenWithCF(cf_names, &options);
+  options.table_properties_collector_factories.push_back(
+      std::make_shared<TestPropertiesCollectorFactory>());
+  CreateAndReopenWithCF(cf_names, options);

  ASSERT_OK(Put(1, "pikachu", std::string(90000, 'p')));
  ASSERT_OK(Put(2, "ilya", std::string(90000, 'i')));
@@ -308,7 +251,7 @@ TEST_F(EventListenerTest, OnSingleDBFlushTest) {
  ASSERT_OK(Put(5, "nikitich", std::string(90000, 'n')));
  ASSERT_OK(Put(6, "alyosha", std::string(90000, 'a')));
  ASSERT_OK(Put(7, "popovich", std::string(90000, 'p')));
-  for (size_t i = 1; i < 8; ++i) {
+  for (int i = 1; i < 8; ++i) {
    ASSERT_OK(Flush(i));
    dbfull()->TEST_WaitForFlushMemTable();
    ASSERT_EQ(listener->flushed_dbs_.size(), i);
@@ -330,10 +273,12 @@ TEST_F(EventListenerTest, MultiCF) {
 #endif  // ROCKSDB_USING_THREAD_STATUS
  TestFlushListener* listener = new TestFlushListener(options.env);
  options.listeners.emplace_back(listener);
+  options.table_properties_collector_factories.push_back(
+      std::make_shared<TestPropertiesCollectorFactory>());
  std::vector<std::string> cf_names = {
      "pikachu", "ilya", "muromec", "dobrynia",
      "nikitich", "alyosha", "popovich"};
-  CreateAndReopenWithCF(cf_names, &options);
+  CreateAndReopenWithCF(cf_names, options);

  ASSERT_OK(Put(1, "pikachu", std::string(90000, 'p')));
  ASSERT_OK(Put(2, "ilya", std::string(90000, 'i')));
@@ -342,7 +287,7 @@ TEST_F(EventListenerTest, MultiCF) {
  ASSERT_OK(Put(5, "nikitich", std::string(90000, 'n')));
  ASSERT_OK(Put(6, "alyosha", std::string(90000, 'a')));
  ASSERT_OK(Put(7, "popovich", std::string(90000, 'p')));
-  for (size_t i = 1; i < 8; ++i) {
+  for (int i = 1; i < 8; ++i) {
    ASSERT_OK(Flush(i));
    ASSERT_EQ(listener->flushed_dbs_.size(), i);
    ASSERT_EQ(listener->flushed_column_family_names_.size(), i);
@@ -360,6 +305,8 @@ TEST_F(EventListenerTest, MultiDBMultiListeners) {
 #if ROCKSDB_USING_THREAD_STATUS
  options.enable_thread_tracking = true;
 #endif  // ROCKSDB_USING_THREAD_STATUS
+  options.table_properties_collector_factories.push_back(
+      std::make_shared<TestPropertiesCollectorFactory>());
  std::vector<TestFlushListener*> listeners;
  const int kNumDBs = 5;
  const int kNumListeners = 10;
@@ -454,8 +401,10 @@ TEST_F(EventListenerTest, DisableBGCompaction) {
  options.compaction_style = kCompactionStyleNone;
  options.compression = kNoCompression;
  options.write_buffer_size = 100000;  // Small write buffer
+  options.table_properties_collector_factories.push_back(
+      std::make_shared<TestPropertiesCollectorFactory>());

-  CreateAndReopenWithCF({"pikachu"}, &options);
+  CreateAndReopenWithCF({"pikachu"}, options);
  ColumnFamilyMetaData cf_meta;
  db_->GetColumnFamilyMetaData(handles_[1], &cf_meta);

@@ -469,6 +418,167 @@ TEST_F(EventListenerTest, DisableBGCompaction) {
  ASSERT_GE(listener->slowdown_count, kSlowdownTrigger * 9);
 }

+class TestCompactionReasonListener : public EventListener {
+ public:
+  void OnCompactionCompleted(DB* db, const CompactionJobInfo& ci) override {
+    std::lock_guard<std::mutex> lock(mutex_);
+    compaction_reasons_.push_back(ci.compaction_reason);
+  }
+
+  std::vector<CompactionReason> compaction_reasons_;
+  std::mutex mutex_;
+};
+
+TEST_F(EventListenerTest, CompactionReasonLevel) {
+  Options options;
+  options.create_if_missing = true;
+  options.memtable_factory.reset(
+      new SpecialSkipListFactory(DBTestBase::kNumKeysByGenerateNewRandomFile));
+
+  TestCompactionReasonListener* listener = new TestCompactionReasonListener();
+  options.listeners.emplace_back(listener);
+
+  options.level0_file_num_compaction_trigger = 4;
+  options.compaction_style = kCompactionStyleLevel;
+
+  DestroyAndReopen(options);
+  Random rnd(301);
+
+  // Write 4 files in L0
+  for (int i = 0; i < 4; i++) {
+    GenerateNewRandomFile(&rnd);
+  }
+  dbfull()->TEST_WaitForCompact();
+
+  ASSERT_EQ(listener->compaction_reasons_.size(), 1);
+  ASSERT_EQ(listener->compaction_reasons_[0],
+            CompactionReason::kLevelL0FilesNum);
+
+  DestroyAndReopen(options);
+
+  // Write 3 non-overlapping files in L0
+  for (int k = 1; k <= 30; k++) {
+    ASSERT_OK(Put(Key(k), Key(k)));
+    if (k % 10 == 0) {
+      Flush();
+    }
+  }
+
+  // Do a trivial move from L0 -> L1
+  db_->CompactRange(CompactRangeOptions(), nullptr, nullptr);
+
+  options.max_bytes_for_level_base = 1;
+  Close();
+  listener->compaction_reasons_.clear();
+  Reopen(options);
+
+  dbfull()->TEST_WaitForCompact();
+  ASSERT_GT(listener->compaction_reasons_.size(), 1);
+
+  for (auto compaction_reason : listener->compaction_reasons_) {
+    ASSERT_EQ(compaction_reason, CompactionReason::kLevelMaxLevelSize);
+  }
+
+  options.disable_auto_compactions = true;
+  Close();
+  listener->compaction_reasons_.clear();
+  Reopen(options);
+
+  db_->CompactRange(CompactRangeOptions(), nullptr, nullptr);
+  ASSERT_GT(listener->compaction_reasons_.size(), 0);
+  for (auto compaction_reason : listener->compaction_reasons_) {
+    ASSERT_EQ(compaction_reason, CompactionReason::kManualCompaction);
+  }
+}
+
+TEST_F(EventListenerTest, CompactionReasonUniversal) {
+  Options options;
+  options.create_if_missing = true;
+  options.memtable_factory.reset(
+      new SpecialSkipListFactory(DBTestBase::kNumKeysByGenerateNewRandomFile));
+
+  TestCompactionReasonListener* listener = new TestCompactionReasonListener();
+  options.listeners.emplace_back(listener);
+
+  options.compaction_style = kCompactionStyleUniversal;
+
+  Random rnd(301);
+
+  options.level0_file_num_compaction_trigger = 8;
+  options.compaction_options_universal.max_size_amplification_percent = 100000;
+  options.compaction_options_universal.size_ratio = 100000;
+  DestroyAndReopen(options);
+  listener->compaction_reasons_.clear();
+
+  // Write 8 files in L0
+  for (int i = 0; i < 8; i++) {
+    GenerateNewRandomFile(&rnd);
+  }
+  dbfull()->TEST_WaitForCompact();
+
+  ASSERT_GT(listener->compaction_reasons_.size(), 0);
+  for (auto compaction_reason : listener->compaction_reasons_) {
+    ASSERT_EQ(compaction_reason, CompactionReason::kUniversalSortedRunNum);
+  }
+
+  options.level0_file_num_compaction_trigger = 8;
+  options.compaction_options_universal.max_size_amplification_percent = 1;
+  options.compaction_options_universal.size_ratio = 100000;
+
+  DestroyAndReopen(options);
+  listener->compaction_reasons_.clear();
+
+  // Write 8 files in L0
+  for (int i = 0; i < 8; i++) {
+    GenerateNewRandomFile(&rnd);
+  }
+  dbfull()->TEST_WaitForCompact();
+
+  ASSERT_GT(listener->compaction_reasons_.size(), 0);
+  for (auto compaction_reason : listener->compaction_reasons_) {
+    ASSERT_EQ(compaction_reason, CompactionReason::kUniversalSizeAmplification);
+  }
+
+  options.disable_auto_compactions = true;
+  Close();
+  listener->compaction_reasons_.clear();
+  Reopen(options);
+
+  db_->CompactRange(CompactRangeOptions(), nullptr, nullptr);
+
+  ASSERT_GT(listener->compaction_reasons_.size(), 0);
+  for (auto compaction_reason : listener->compaction_reasons_) {
+    ASSERT_EQ(compaction_reason, CompactionReason::kManualCompaction);
+  }
+}
+
+TEST_F(EventListenerTest, CompactionReasonFIFO) {
+  Options options;
+  options.create_if_missing = true;
+  options.memtable_factory.reset(
+      new SpecialSkipListFactory(DBTestBase::kNumKeysByGenerateNewRandomFile));
+
+  TestCompactionReasonListener* listener = new TestCompactionReasonListener();
+  options.listeners.emplace_back(listener);
+
+  options.level0_file_num_compaction_trigger = 4;
+  options.compaction_style = kCompactionStyleFIFO;
+  options.compaction_options_fifo.max_table_files_size = 1;
+
+  DestroyAndReopen(options);
+  Random rnd(301);
+
+  // Write 4 files in L0
+  for (int i = 0; i < 4; i++) {
+    GenerateNewRandomFile(&rnd);
+  }
+  dbfull()->TEST_WaitForCompact();
+
+  ASSERT_GT(listener->compaction_reasons_.size(), 0);
+  for (auto compaction_reason : listener->compaction_reasons_) {
+    ASSERT_EQ(compaction_reason, CompactionReason::kFIFOMaxSize);
+  }
+}
 }  // namespace rocksdb

 #endif  // ROCKSDB_LITE
@@ -477,4 +587,3 @@ int main(int argc, char** argv) {
  ::testing::InitGoogleTest(&argc, argv);
  return RUN_ALL_TESTS();
 }
-
@@ -22,14 +22,24 @@ enum RecordType {
  // For fragments
  kFirstType = 2,
  kMiddleType = 3,
-  kLastType = 4
+  kLastType = 4,
+
+  // For recycled log files
+  kRecyclableFullType = 5,
+  kRecyclableFirstType = 6,
+  kRecyclableMiddleType = 7,
+  kRecyclableLastType = 8,
 };
-static const int kMaxRecordType = kLastType;
+static const int kMaxRecordType = kRecyclableLastType;

 static const unsigned int kBlockSize = 32768;

 // Header is checksum (4 bytes), type (1 byte), length (2 bytes).
 static const int kHeaderSize = 4 + 1 + 2;

+// Recyclable header is checksum (4 bytes), type (1 byte), log number
+// (4 bytes), length (2 bytes).
+static const int kRecyclableHeaderSize = 4 + 1 + 4 + 2;
+
 }  // namespace log
 }  // namespace rocksdb
@@ -21,9 +21,12 @@ namespace log {
 Reader::Reporter::~Reporter() {
 }

-Reader::Reader(unique_ptr<SequentialFileReader>&& _file, Reporter* reporter,
-               bool checksum, uint64_t initial_offset)
-    : file_(std::move(_file)),
+Reader::Reader(std::shared_ptr<Logger> info_log,
+	       unique_ptr<SequentialFileReader>&& _file,
+               Reporter* reporter, bool checksum, uint64_t initial_offset,
+               uint64_t log_num)
+    : info_log_(info_log),
+      file_(std::move(_file)),
      reporter_(reporter),
      checksum_(checksum),
      backing_store_(new char[kBlockSize]),
@@ -33,7 +36,8 @@ Reader::Reader(unique_ptr<SequentialFileReader>&& _file, Reporter* reporter,
      eof_offset_(0),
      last_record_offset_(0),
      end_of_buffer_offset_(0),
-      initial_offset_(initial_offset) {}
+      initial_offset_(initial_offset),
+      log_number_(log_num) {}

 Reader::~Reader() {
  delete[] backing_store_;
@@ -62,8 +66,15 @@ bool Reader::SkipToInitialBlock() {
  return true;
 }

+// For kAbsoluteConsistency, on clean shutdown we don't expect any error
+// in the log files.  For other modes, we can ignore only incomplete records
+// in the last log file, which are presumably due to a write in progress
+// during restart (or from log recycling).
+//
+// TODO krad: Evaluate if we need to move to a more strict mode where we
+// restrict the inconsistency to only the last log
 bool Reader::ReadRecord(Slice* record, std::string* scratch,
-                        const bool report_eof_inconsistency) {
+                        WALRecoveryMode wal_recovery_mode) {
  if (last_record_offset_ < initial_offset_) {
    if (!SkipToInitialBlock()) {
      return false;
@@ -80,10 +91,11 @@ bool Reader::ReadRecord(Slice* record, std::string* scratch,
  Slice fragment;
  while (true) {
    uint64_t physical_record_offset = end_of_buffer_offset_ - buffer_.size();
-    const unsigned int record_type =
-        ReadPhysicalRecord(&fragment, report_eof_inconsistency);
+    size_t drop_size;
+    const unsigned int record_type = ReadPhysicalRecord(&fragment, &drop_size);
    switch (record_type) {
      case kFullType:
+      case kRecyclableFullType:
        if (in_fragmented_record && !scratch->empty()) {
          // Handle bug in earlier versions of log::Writer where
          // it could emit an empty kFirstType record at the tail end
@@ -98,6 +110,7 @@ bool Reader::ReadRecord(Slice* record, std::string* scratch,
        return true;

      case kFirstType:
+      case kRecyclableFirstType:
        if (in_fragmented_record && !scratch->empty()) {
          // Handle bug in earlier versions of log::Writer where
          // it could emit an empty kFirstType record at the tail end
@@ -111,6 +124,7 @@ bool Reader::ReadRecord(Slice* record, std::string* scratch,
        break;

      case kMiddleType:
+      case kRecyclableMiddleType:
        if (!in_fragmented_record) {
          ReportCorruption(fragment.size(),
                           "missing start of fragmented record(1)");
@@ -120,6 +134,7 @@ bool Reader::ReadRecord(Slice* record, std::string* scratch,
        break;

      case kLastType:
+      case kRecyclableLastType:
        if (!in_fragmented_record) {
          ReportCorruption(fragment.size(),
                           "missing start of fragmented record(2)");
@@ -131,9 +146,17 @@ bool Reader::ReadRecord(Slice* record, std::string* scratch,
        }
        break;

+      case kBadHeader:
+        if (wal_recovery_mode == WALRecoveryMode::kAbsoluteConsistency) {
+          // in clean shutdown we don't expect any error in the log files
+          ReportCorruption(drop_size, "truncated header");
+        }
+      // fall-thru
+
      case kEof:
        if (in_fragmented_record) {
-          if (report_eof_inconsistency) {
+          if (wal_recovery_mode == WALRecoveryMode::kAbsoluteConsistency) {
+            // in clean shutdown we don't expect any error in the log files
            ReportCorruption(scratch->size(), "error reading trailing data");
          }
          // This can be caused by the writer dying immediately after
@@ -143,6 +166,23 @@ bool Reader::ReadRecord(Slice* record, std::string* scratch,
        }
        return false;

+      case kOldRecord:
+        if (wal_recovery_mode != WALRecoveryMode::kSkipAnyCorruptedRecords) {
+          // Treat a record from a previous instance of the log as EOF.
+          if (in_fragmented_record) {
+            if (wal_recovery_mode == WALRecoveryMode::kAbsoluteConsistency) {
+              // in clean shutdown we don't expect any error in the log files
+              ReportCorruption(scratch->size(), "error reading trailing data");
+            }
+            // This can be caused by the writer dying immediately after
+            //  writing a physical record but before completing the next; don't
+            //  treat it as a corruption, just ignore the entire logical record.
+            scratch->clear();
+          }
+          return false;
+        }
+      // fall-thru
+
      case kBadRecord:
        if (in_fragmented_record) {
          ReportCorruption(scratch->size(), "error in middle of record");
@@ -244,36 +284,49 @@ void Reader::ReportDrop(size_t bytes, const Status& reason) {
  }
 }

-unsigned int Reader::ReadPhysicalRecord(Slice* result,
-                                        const bool report_eof_inconsistency) {
+bool Reader::ReadMore(size_t* drop_size, int *error) {
+  if (!eof_ && !read_error_) {
+    // Last read was a full read, so this is a trailer to skip
+    buffer_.clear();
+    Status status = file_->Read(kBlockSize, &buffer_, backing_store_);
+    end_of_buffer_offset_ += buffer_.size();
+    if (!status.ok()) {
+      buffer_.clear();
+      ReportDrop(kBlockSize, status);
+      read_error_ = true;
+      *error = kEof;
+      return false;
+    } else if (buffer_.size() < (size_t)kBlockSize) {
+      eof_ = true;
+      eof_offset_ = buffer_.size();
+    }
+    return true;
+  } else {
+    // Note that if buffer_ is non-empty, we have a truncated header at the
+    //  end of the file, which can be caused by the writer crashing in the
+    //  middle of writing the header. Unless explicitly requested we don't
+    //  considering this an error, just report EOF.
+    if (buffer_.size()) {
+      *drop_size = buffer_.size();
+      buffer_.clear();
+      *error = kBadHeader;
+      return false;
+    }
+    buffer_.clear();
+    *error = kEof;
+    return false;
+  }
+}
+
+unsigned int Reader::ReadPhysicalRecord(Slice* result, size_t* drop_size) {
  while (true) {
+    // We need at least the minimum header size
    if (buffer_.size() < (size_t)kHeaderSize) {
-      if (!eof_ && !read_error_) {
-        // Last read was a full read, so this is a trailer to skip
-        buffer_.clear();
-        Status status = file_->Read(kBlockSize, &buffer_, backing_store_);
-        end_of_buffer_offset_ += buffer_.size();
-        if (!status.ok()) {
-          buffer_.clear();
-          ReportDrop(kBlockSize, status);
-          read_error_ = true;
-          return kEof;
-        } else if (buffer_.size() < (size_t)kBlockSize) {
-          eof_ = true;
-          eof_offset_ = buffer_.size();
-        }
-        continue;
-      } else {
-        // Note that if buffer_ is non-empty, we have a truncated header at the
-        //  end of the file, which can be caused by the writer crashing in the
-        //  middle of writing the header. Unless explicitly requested we don't
-        //  considering this an error, just report EOF.
-        if (buffer_.size() && report_eof_inconsistency) {
-          ReportCorruption(buffer_.size(), "truncated header");
-        }
-        buffer_.clear();
-        return kEof;
+      int r;
+      if (!ReadMore(drop_size, &r)) {
+	return r;
      }
+      continue;
    }

    // Parse the header
@@ -282,18 +335,34 @@ unsigned int Reader::ReadPhysicalRecord(Slice* result,
    const uint32_t b = static_cast<uint32_t>(header[5]) & 0xff;
    const unsigned int type = header[6];
    const uint32_t length = a | (b << 8);
-    if (kHeaderSize + length > buffer_.size()) {
-      size_t drop_size = buffer_.size();
+    int header_size = kHeaderSize;
+    if (type >= kRecyclableFullType && type <= kRecyclableLastType) {
+      header_size = kRecyclableHeaderSize;
+      // We need enough for the larger header
+      if (buffer_.size() < (size_t)kRecyclableHeaderSize) {
+	int r;
+	if (!ReadMore(drop_size, &r)) {
+          return r;
+        }
+	continue;
+      }
+      const uint32_t log_num = DecodeFixed32(header + 7);
+      if (log_num != log_number_) {
+        return kOldRecord;
+      }
+    }
+    if (header_size + length > buffer_.size()) {
+      *drop_size = buffer_.size();
      buffer_.clear();
      if (!eof_) {
-        ReportCorruption(drop_size, "bad record length");
+        ReportCorruption(*drop_size, "bad record length");
        return kBadRecord;
      }
      // If the end of the file has been reached without reading |length| bytes
      // of payload, assume the writer died in the middle of writing the record.
      // Don't report a corruption unless requested.
-      if (drop_size && report_eof_inconsistency) {
-        ReportCorruption(drop_size, "truncated header");
+      if (*drop_size) {
+        return kBadHeader;
      }
      return kEof;
    }
@@ -311,29 +380,29 @@ unsigned int Reader::ReadPhysicalRecord(Slice* result,
    // Check crc
    if (checksum_) {
      uint32_t expected_crc = crc32c::Unmask(DecodeFixed32(header));
-      uint32_t actual_crc = crc32c::Value(header + 6, 1 + length);
+      uint32_t actual_crc = crc32c::Value(header + 6, length + header_size - 6);
      if (actual_crc != expected_crc) {
        // Drop the rest of the buffer since "length" itself may have
        // been corrupted and if we trust it, we could find some
        // fragment of a real log record that just happens to look
        // like a valid log record.
-        size_t drop_size = buffer_.size();
+        *drop_size = buffer_.size();
        buffer_.clear();
-        ReportCorruption(drop_size, "checksum mismatch");
+        ReportCorruption(*drop_size, "checksum mismatch");
        return kBadRecord;
      }
    }

-    buffer_.remove_prefix(kHeaderSize + length);
+    buffer_.remove_prefix(header_size + length);

    // Skip physical record that started before initial_offset_
-    if (end_of_buffer_offset_ - buffer_.size() - kHeaderSize - length <
+    if (end_of_buffer_offset_ - buffer_.size() - header_size - length <
        initial_offset_) {
      result->clear();
      return kBadRecord;
    }

-    *result = Slice(header + kHeaderSize, length);
+    *result = Slice(header + header_size, length);
    return type;
  }
 }
@@ -14,10 +14,12 @@
 #include "db/log_format.h"
 #include "rocksdb/slice.h"
 #include "rocksdb/status.h"
+#include "rocksdb/options.h"

 namespace rocksdb {

 class SequentialFileReader;
+class Logger;
 using std::unique_ptr;

 namespace log {
@@ -51,8 +53,10 @@ class Reader {
  //
  // The Reader will start reading at the first record located at physical
  // position >= initial_offset within the file.
-  Reader(unique_ptr<SequentialFileReader>&& file, Reporter* reporter,
-         bool checksum, uint64_t initial_offset);
+  Reader(std::shared_ptr<Logger> info_log,
+	 unique_ptr<SequentialFileReader>&& file,
+         Reporter* reporter, bool checksum, uint64_t initial_offset,
+         uint64_t log_num);

  ~Reader();

@@ -62,7 +66,8 @@ class Reader {
  // will only be valid until the next mutating operation on this
  // reader or the next mutation to *scratch.
  bool ReadRecord(Slice* record, std::string* scratch,
-                  bool report_eof_inconsistency = false);
+                  WALRecoveryMode wal_recovery_mode =
+                      WALRecoveryMode::kTolerateCorruptedTailRecords);

  // Returns the physical offset of the last record returned by ReadRecord.
  //
@@ -84,6 +89,7 @@ class Reader {
  SequentialFileReader* file() { return file_.get(); }

 private:
+  std::shared_ptr<Logger> info_log_;
  const unique_ptr<SequentialFileReader> file_;
  Reporter* const reporter_;
  bool const checksum_;
@@ -104,6 +110,9 @@ class Reader {
  // Offset at which to start looking for the first record to return
  uint64_t const initial_offset_;

+  // which log number this is
+  uint64_t const log_number_;
+
  // Extend record types with the following special values
  enum {
    kEof = kMaxRecordType + 1,
@@ -112,7 +121,11 @@ class Reader {
    // * The record has an invalid CRC (ReadPhysicalRecord reports a drop)
    // * The record is a 0-length record (No drop is reported)
    // * The record is below constructor's initial_offset (No drop is reported)
-    kBadRecord = kMaxRecordType + 2
+    kBadRecord = kMaxRecordType + 2,
+    // Returned when we fail to read a valid header.
+    kBadHeader = kMaxRecordType + 3,
+    // Returned when we read an old record from a previous user of the log.
+    kOldRecord = kMaxRecordType + 4,
  };

  // Skips all blocks that are completely before "initial_offset_".
@@ -121,8 +134,10 @@ class Reader {
  bool SkipToInitialBlock();

  // Return type, or one of the preceding special values
-  unsigned int ReadPhysicalRecord(Slice* result,
-                                  bool report_eof_inconsistency = false);
+  unsigned int ReadPhysicalRecord(Slice* result, size_t* drop_size);
+
+  // Read some more
+  bool ReadMore(size_t* drop_size, int *error);

  // Reports dropped bytes to the reporter.
  // buffer_ must be updated to remove the dropped bytes prior to invocation.
@@ -43,7 +43,7 @@ static std::string RandomSkewedString(int i, Random* rnd) {
  return BigString(NumberString(i), rnd->Skewed(17));
 }

-class LogTest : public testing::Test {
+class LogTest : public ::testing::TestWithParam<int> {
 private:
  class StringSource : public SequentialFile {
   public:
@@ -153,19 +153,26 @@ class LogTest : public testing::Test {

  // Record metadata for testing initial offset functionality
  static size_t initial_offset_record_sizes_[];
-  static uint64_t initial_offset_last_record_offsets_[];
+  uint64_t initial_offset_last_record_offsets_[4];

 public:
  LogTest()
      : reader_contents_(),
-        dest_holder_(
-            test::GetWritableFileWriter(
-              new test::StringSink(&reader_contents_))),
+        dest_holder_(test::GetWritableFileWriter(
+            new test::StringSink(&reader_contents_))),
        source_holder_(
            test::GetSequentialFileReader(new StringSource(reader_contents_))),
-        writer_(std::move(dest_holder_)),
-        reader_(std::move(source_holder_), &report_, true /*checksum*/,
-                0 /*initial_offset*/) {}
+        writer_(std::move(dest_holder_), 123, GetParam()),
+        reader_(NULL, std::move(source_holder_), &report_, true /*checksum*/,
+                0 /*initial_offset*/, 123) {
+    int header_size = GetParam() ? kRecyclableHeaderSize : kHeaderSize;
+    initial_offset_last_record_offsets_[0] = 0;
+    initial_offset_last_record_offsets_[1] = header_size + 10000;
+    initial_offset_last_record_offsets_[2] = 2 * (header_size + 10000);
+    initial_offset_last_record_offsets_[3] = 2 * (header_size + 10000) +
+                                             (2 * log::kBlockSize - 1000) +
+                                             3 * header_size;
+  }

  void Write(const std::string& msg) {
    writer_.AddRecord(Slice(msg));
@@ -175,10 +182,11 @@ class LogTest : public testing::Test {
    return dest_contents().size();
  }

-  std::string Read(const bool report_eof_inconsistency = false) {
+  std::string Read(const WALRecoveryMode wal_recovery_mode =
+                       WALRecoveryMode::kTolerateCorruptedTailRecords) {
    std::string scratch;
    Slice record;
-    if (reader_.ReadRecord(&record, &scratch, report_eof_inconsistency)) {
+    if (reader_.ReadRecord(&record, &scratch, wal_recovery_mode)) {
      return record.ToString();
    } else {
      return "EOF";
@@ -200,9 +208,11 @@ class LogTest : public testing::Test {
    dest->Drop(bytes);
  }

-  void FixChecksum(int header_offset, int len) {
+  void FixChecksum(int header_offset, int len, bool recyclable) {
    // Compute crc of type/len/data
-    uint32_t crc = crc32c::Value(&dest_contents()[header_offset+6], 1 + len);
+    int header_size = recyclable ? kRecyclableHeaderSize : kHeaderSize;
+    uint32_t crc = crc32c::Value(&dest_contents()[header_offset + 6],
+                                 header_size - 6 + len);
    crc = crc32c::Mask(crc);
    EncodeFixed32(&dest_contents()[header_offset], crc);
  }
@@ -259,8 +269,8 @@ class LogTest : public testing::Test {
    unique_ptr<SequentialFileReader> file_reader(
        test::GetSequentialFileReader(new StringSource(reader_contents_)));
    unique_ptr<Reader> offset_reader(
-        new Reader(std::move(file_reader), &report_, true /*checksum*/,
-                   WrittenBytes() + offset_past_end));
+        new Reader(NULL, std::move(file_reader), &report_,
+                   true /*checksum*/, WrittenBytes() + offset_past_end, 123));
    Slice record;
    std::string scratch;
    ASSERT_TRUE(!offset_reader->ReadRecord(&record, &scratch));
@@ -271,8 +281,9 @@ class LogTest : public testing::Test {
    WriteInitialOffsetLog();
    unique_ptr<SequentialFileReader> file_reader(
        test::GetSequentialFileReader(new StringSource(reader_contents_)));
-    unique_ptr<Reader> offset_reader(new Reader(
-        std::move(file_reader), &report_, true /*checksum*/, initial_offset));
+    unique_ptr<Reader> offset_reader(
+        new Reader(NULL, std::move(file_reader), &report_,
+                   true /*checksum*/, initial_offset, 123));
    Slice record;
    std::string scratch;
    ASSERT_TRUE(offset_reader->ReadRecord(&record, &scratch));
@@ -291,16 +302,9 @@ size_t LogTest::initial_offset_record_sizes_[] =
     2 * log::kBlockSize - 1000,  // Span three blocks
     1};

-uint64_t LogTest::initial_offset_last_record_offsets_[] =
-    {0,
-     kHeaderSize + 10000,
-     2 * (kHeaderSize + 10000),
-     2 * (kHeaderSize + 10000) +
-         (2 * log::kBlockSize - 1000) + 3 * kHeaderSize};
+TEST_P(LogTest, Empty) { ASSERT_EQ("EOF", Read()); }

-TEST_F(LogTest, Empty) { ASSERT_EQ("EOF", Read()); }
-
-TEST_F(LogTest, ReadWrite) {
+TEST_P(LogTest, ReadWrite) {
  Write("foo");
  Write("bar");
  Write("");
@@ -313,7 +317,7 @@ TEST_F(LogTest, ReadWrite) {
  ASSERT_EQ("EOF", Read());  // Make sure reads at eof work
 }

-TEST_F(LogTest, ManyBlocks) {
+TEST_P(LogTest, ManyBlocks) {
  for (int i = 0; i < 100000; i++) {
    Write(NumberString(i));
  }
@@ -323,7 +327,7 @@ TEST_F(LogTest, ManyBlocks) {
  ASSERT_EQ("EOF", Read());
 }

-TEST_F(LogTest, Fragmentation) {
+TEST_P(LogTest, Fragmentation) {
  Write("small");
  Write(BigString("medium", 50000));
  Write(BigString("large", 100000));
@@ -333,11 +337,12 @@ TEST_F(LogTest, Fragmentation) {
  ASSERT_EQ("EOF", Read());
 }

-TEST_F(LogTest, MarginalTrailer) {
+TEST_P(LogTest, MarginalTrailer) {
  // Make a trailer that is exactly the same length as an empty record.
-  const int n = kBlockSize - 2*kHeaderSize;
+  int header_size = GetParam() ? kRecyclableHeaderSize : kHeaderSize;
+  const int n = kBlockSize - 2 * header_size;
  Write(BigString("foo", n));
-  ASSERT_EQ((unsigned int)(kBlockSize - kHeaderSize), WrittenBytes());
+  ASSERT_EQ((unsigned int)(kBlockSize - header_size), WrittenBytes());
  Write("");
  Write("bar");
  ASSERT_EQ(BigString("foo", n), Read());
@@ -346,11 +351,12 @@ TEST_F(LogTest, MarginalTrailer) {
  ASSERT_EQ("EOF", Read());
 }

-TEST_F(LogTest, MarginalTrailer2) {
+TEST_P(LogTest, MarginalTrailer2) {
  // Make a trailer that is exactly the same length as an empty record.
-  const int n = kBlockSize - 2*kHeaderSize;
+  int header_size = GetParam() ? kRecyclableHeaderSize : kHeaderSize;
+  const int n = kBlockSize - 2 * header_size;
  Write(BigString("foo", n));
-  ASSERT_EQ((unsigned int)(kBlockSize - kHeaderSize), WrittenBytes());
+  ASSERT_EQ((unsigned int)(kBlockSize - header_size), WrittenBytes());
  Write("bar");
  ASSERT_EQ(BigString("foo", n), Read());
  ASSERT_EQ("bar", Read());
@@ -359,10 +365,11 @@ TEST_F(LogTest, MarginalTrailer2) {
  ASSERT_EQ("", ReportMessage());
 }

-TEST_F(LogTest, ShortTrailer) {
-  const int n = kBlockSize - 2*kHeaderSize + 4;
+TEST_P(LogTest, ShortTrailer) {
+  int header_size = GetParam() ? kRecyclableHeaderSize : kHeaderSize;
+  const int n = kBlockSize - 2 * header_size + 4;
  Write(BigString("foo", n));
-  ASSERT_EQ((unsigned int)(kBlockSize - kHeaderSize + 4), WrittenBytes());
+  ASSERT_EQ((unsigned int)(kBlockSize - header_size + 4), WrittenBytes());
  Write("");
  Write("bar");
  ASSERT_EQ(BigString("foo", n), Read());
@@ -371,15 +378,16 @@ TEST_F(LogTest, ShortTrailer) {
  ASSERT_EQ("EOF", Read());
 }

-TEST_F(LogTest, AlignedEof) {
-  const int n = kBlockSize - 2*kHeaderSize + 4;
+TEST_P(LogTest, AlignedEof) {
+  int header_size = GetParam() ? kRecyclableHeaderSize : kHeaderSize;
+  const int n = kBlockSize - 2 * header_size + 4;
  Write(BigString("foo", n));
-  ASSERT_EQ((unsigned int)(kBlockSize - kHeaderSize + 4), WrittenBytes());
+  ASSERT_EQ((unsigned int)(kBlockSize - header_size + 4), WrittenBytes());
  ASSERT_EQ(BigString("foo", n), Read());
  ASSERT_EQ("EOF", Read());
 }

-TEST_F(LogTest, RandomRead) {
+TEST_P(LogTest, RandomRead) {
  const int N = 500;
  Random write_rnd(301);
  for (int i = 0; i < N; i++) {
@@ -394,7 +402,7 @@ TEST_F(LogTest, RandomRead) {

 // Tests of all the error paths in log_reader.cc follow:

-TEST_F(LogTest, ReadError) {
+TEST_P(LogTest, ReadError) {
  Write("foo");
  ForceError();
  ASSERT_EQ("EOF", Read());
@@ -402,17 +410,17 @@ TEST_F(LogTest, ReadError) {
  ASSERT_EQ("OK", MatchError("read error"));
 }

-TEST_F(LogTest, BadRecordType) {
+TEST_P(LogTest, BadRecordType) {
  Write("foo");
  // Type is stored in header[6]
  IncrementByte(6, 100);
-  FixChecksum(0, 3);
+  FixChecksum(0, 3, false);
  ASSERT_EQ("EOF", Read());
  ASSERT_EQ(3U, DroppedBytes());
  ASSERT_EQ("OK", MatchError("unknown record type"));
 }

-TEST_F(LogTest, TruncatedTrailingRecordIsIgnored) {
+TEST_P(LogTest, TruncatedTrailingRecordIsIgnored) {
  Write("foo");
  ShrinkSize(4);   // Drop all payload as well as a header byte
  ASSERT_EQ("EOF", Read());
@@ -421,17 +429,18 @@ TEST_F(LogTest, TruncatedTrailingRecordIsIgnored) {
  ASSERT_EQ("", ReportMessage());
 }

-TEST_F(LogTest, TruncatedTrailingRecordIsNotIgnored) {
+TEST_P(LogTest, TruncatedTrailingRecordIsNotIgnored) {
  Write("foo");
  ShrinkSize(4);  // Drop all payload as well as a header byte
-  ASSERT_EQ("EOF", Read(/*report_eof_inconsistency*/ true));
+  ASSERT_EQ("EOF", Read(WALRecoveryMode::kAbsoluteConsistency));
  // Truncated last record is ignored, not treated as an error
  ASSERT_GT(DroppedBytes(), 0U);
  ASSERT_EQ("OK", MatchError("Corruption: truncated header"));
 }

-TEST_F(LogTest, BadLength) {
-  const int kPayloadSize = kBlockSize - kHeaderSize;
+TEST_P(LogTest, BadLength) {
+  int header_size = GetParam() ? kRecyclableHeaderSize : kHeaderSize;
+  const int kPayloadSize = kBlockSize - header_size;
  Write(BigString("bar", kPayloadSize));
  Write("foo");
  // Least significant size byte is stored in header[4].
@@ -441,7 +450,7 @@ TEST_F(LogTest, BadLength) {
  ASSERT_EQ("OK", MatchError("bad record length"));
 }

-TEST_F(LogTest, BadLengthAtEndIsIgnored) {
+TEST_P(LogTest, BadLengthAtEndIsIgnored) {
  Write("foo");
  ShrinkSize(1);
  ASSERT_EQ("EOF", Read());
@@ -449,63 +458,63 @@ TEST_F(LogTest, BadLengthAtEndIsIgnored) {
  ASSERT_EQ("", ReportMessage());
 }

-TEST_F(LogTest, BadLengthAtEndIsNotIgnored) {
+TEST_P(LogTest, BadLengthAtEndIsNotIgnored) {
  Write("foo");
  ShrinkSize(1);
-  ASSERT_EQ("EOF", Read(/*report_eof_inconsistency=*/true));
+  ASSERT_EQ("EOF", Read(WALRecoveryMode::kAbsoluteConsistency));
  ASSERT_GT(DroppedBytes(), 0U);
  ASSERT_EQ("OK", MatchError("Corruption: truncated header"));
 }

-TEST_F(LogTest, ChecksumMismatch) {
-  Write("foo");
-  IncrementByte(0, 10);
+TEST_P(LogTest, ChecksumMismatch) {
+  Write("foooooo");
+  IncrementByte(0, 14);
  ASSERT_EQ("EOF", Read());
-  ASSERT_EQ(10U, DroppedBytes());
+  ASSERT_EQ(14U + 4 * !!GetParam(), DroppedBytes());
  ASSERT_EQ("OK", MatchError("checksum mismatch"));
 }

-TEST_F(LogTest, UnexpectedMiddleType) {
+TEST_P(LogTest, UnexpectedMiddleType) {
  Write("foo");
-  SetByte(6, kMiddleType);
-  FixChecksum(0, 3);
+  SetByte(6, GetParam() ? kRecyclableMiddleType : kMiddleType);
+  FixChecksum(0, 3, !!GetParam());
  ASSERT_EQ("EOF", Read());
  ASSERT_EQ(3U, DroppedBytes());
  ASSERT_EQ("OK", MatchError("missing start"));
 }

-TEST_F(LogTest, UnexpectedLastType) {
+TEST_P(LogTest, UnexpectedLastType) {
  Write("foo");
-  SetByte(6, kLastType);
-  FixChecksum(0, 3);
+  SetByte(6, GetParam() ? kRecyclableLastType : kLastType);
+  FixChecksum(0, 3, !!GetParam());
  ASSERT_EQ("EOF", Read());
  ASSERT_EQ(3U, DroppedBytes());
  ASSERT_EQ("OK", MatchError("missing start"));
 }

-TEST_F(LogTest, UnexpectedFullType) {
+TEST_P(LogTest, UnexpectedFullType) {
  Write("foo");
  Write("bar");
-  SetByte(6, kFirstType);
-  FixChecksum(0, 3);
+  SetByte(6, GetParam() ? kRecyclableFirstType : kFirstType);
+  FixChecksum(0, 3, !!GetParam());
  ASSERT_EQ("bar", Read());
  ASSERT_EQ("EOF", Read());
  ASSERT_EQ(3U, DroppedBytes());
  ASSERT_EQ("OK", MatchError("partial record without end"));
 }

-TEST_F(LogTest, UnexpectedFirstType) {
+TEST_P(LogTest, UnexpectedFirstType) {
  Write("foo");
  Write(BigString("bar", 100000));
-  SetByte(6, kFirstType);
-  FixChecksum(0, 3);
+  SetByte(6, GetParam() ? kRecyclableFirstType : kFirstType);
+  FixChecksum(0, 3, !!GetParam());
  ASSERT_EQ(BigString("bar", 100000), Read());
  ASSERT_EQ("EOF", Read());
  ASSERT_EQ(3U, DroppedBytes());
  ASSERT_EQ("OK", MatchError("partial record without end"));
 }

-TEST_F(LogTest, MissingLastIsIgnored) {
+TEST_P(LogTest, MissingLastIsIgnored) {
  Write(BigString("bar", kBlockSize));
  // Remove the LAST block, including header.
  ShrinkSize(14);
@@ -514,16 +523,16 @@ TEST_F(LogTest, MissingLastIsIgnored) {
  ASSERT_EQ(0U, DroppedBytes());
 }

-TEST_F(LogTest, MissingLastIsNotIgnored) {
+TEST_P(LogTest, MissingLastIsNotIgnored) {
  Write(BigString("bar", kBlockSize));
  // Remove the LAST block, including header.
  ShrinkSize(14);
-  ASSERT_EQ("EOF", Read(/*report_eof_inconsistency=*/true));
+  ASSERT_EQ("EOF", Read(WALRecoveryMode::kAbsoluteConsistency));
  ASSERT_GT(DroppedBytes(), 0U);
  ASSERT_EQ("OK", MatchError("Corruption: error reading trailing data"));
 }

-TEST_F(LogTest, PartialLastIsIgnored) {
+TEST_P(LogTest, PartialLastIsIgnored) {
  Write(BigString("bar", kBlockSize));
  // Cause a bad record length in the LAST block.
  ShrinkSize(1);
@@ -532,18 +541,18 @@ TEST_F(LogTest, PartialLastIsIgnored) {
  ASSERT_EQ(0U, DroppedBytes());
 }

-TEST_F(LogTest, PartialLastIsNotIgnored) {
+TEST_P(LogTest, PartialLastIsNotIgnored) {
  Write(BigString("bar", kBlockSize));
  // Cause a bad record length in the LAST block.
  ShrinkSize(1);
-  ASSERT_EQ("EOF", Read(/*report_eof_inconsistency=*/true));
+  ASSERT_EQ("EOF", Read(WALRecoveryMode::kAbsoluteConsistency));
  ASSERT_GT(DroppedBytes(), 0U);
  ASSERT_EQ("OK", MatchError(
                      "Corruption: truncated headerCorruption: "
                      "error reading trailing data"));
 }

-TEST_F(LogTest, ErrorJoinsRecords) {
+TEST_P(LogTest, ErrorJoinsRecords) {
  // Consider two fragmented records:
  //    first(R1) last(R1) first(R2) last(R2)
  // where the middle two fragments disappear.  We do not want
@@ -566,46 +575,60 @@ TEST_F(LogTest, ErrorJoinsRecords) {
  ASSERT_GE(dropped, 2 * kBlockSize);
 }

-TEST_F(LogTest, ReadStart) { CheckInitialOffsetRecord(0, 0); }
+TEST_P(LogTest, ReadStart) { CheckInitialOffsetRecord(0, 0); }

-TEST_F(LogTest, ReadSecondOneOff) { CheckInitialOffsetRecord(1, 1); }
+TEST_P(LogTest, ReadSecondOneOff) { CheckInitialOffsetRecord(1, 1); }

-TEST_F(LogTest, ReadSecondTenThousand) { CheckInitialOffsetRecord(10000, 1); }
+TEST_P(LogTest, ReadSecondTenThousand) { CheckInitialOffsetRecord(10000, 1); }

-TEST_F(LogTest, ReadSecondStart) { CheckInitialOffsetRecord(10007, 1); }
+TEST_P(LogTest, ReadSecondStart) {
+  int header_size = GetParam() ? kRecyclableHeaderSize : kHeaderSize;
+  CheckInitialOffsetRecord(10000 + header_size, 1);
+}

-TEST_F(LogTest, ReadThirdOneOff) { CheckInitialOffsetRecord(10008, 2); }
+TEST_P(LogTest, ReadThirdOneOff) {
+  int header_size = GetParam() ? kRecyclableHeaderSize : kHeaderSize;
+  CheckInitialOffsetRecord(10000 + header_size + 1, 2);
+}

-TEST_F(LogTest, ReadThirdStart) { CheckInitialOffsetRecord(20014, 2); }
+TEST_P(LogTest, ReadThirdStart) {
+  int header_size = GetParam() ? kRecyclableHeaderSize : kHeaderSize;
+  CheckInitialOffsetRecord(20000 + 2 * header_size, 2);
+}

-TEST_F(LogTest, ReadFourthOneOff) { CheckInitialOffsetRecord(20015, 3); }
+TEST_P(LogTest, ReadFourthOneOff) {
+  int header_size = GetParam() ? kRecyclableHeaderSize : kHeaderSize;
+  CheckInitialOffsetRecord(20000 + 2 * header_size + 1, 3);
+}

-TEST_F(LogTest, ReadFourthFirstBlockTrailer) {
+TEST_P(LogTest, ReadFourthFirstBlockTrailer) {
  CheckInitialOffsetRecord(log::kBlockSize - 4, 3);
 }

-TEST_F(LogTest, ReadFourthMiddleBlock) {
+TEST_P(LogTest, ReadFourthMiddleBlock) {
  CheckInitialOffsetRecord(log::kBlockSize + 1, 3);
 }

-TEST_F(LogTest, ReadFourthLastBlock) {
+TEST_P(LogTest, ReadFourthLastBlock) {
  CheckInitialOffsetRecord(2 * log::kBlockSize + 1, 3);
 }

-TEST_F(LogTest, ReadFourthStart) {
+TEST_P(LogTest, ReadFourthStart) {
+  int header_size = GetParam() ? kRecyclableHeaderSize : kHeaderSize;
  CheckInitialOffsetRecord(
-      2 * (kHeaderSize + 1000) + (2 * log::kBlockSize - 1000) + 3 * kHeaderSize,
+      2 * (header_size + 1000) + (2 * log::kBlockSize - 1000) + 3 * header_size,
      3);
 }

-TEST_F(LogTest, ReadEnd) { CheckOffsetPastEndReturnsNoRecords(0); }
+TEST_P(LogTest, ReadEnd) { CheckOffsetPastEndReturnsNoRecords(0); }

-TEST_F(LogTest, ReadPastEnd) { CheckOffsetPastEndReturnsNoRecords(5); }
+TEST_P(LogTest, ReadPastEnd) { CheckOffsetPastEndReturnsNoRecords(5); }

-TEST_F(LogTest, ClearEofSingleBlock) {
+TEST_P(LogTest, ClearEofSingleBlock) {
  Write("foo");
  Write("bar");
-  ForceEOF(3 + kHeaderSize + 2);
+  int header_size = GetParam() ? kRecyclableHeaderSize : kHeaderSize;
+  ForceEOF(3 + header_size + 2);
  ASSERT_EQ("foo", Read());
  UnmarkEOF();
  ASSERT_EQ("bar", Read());
@@ -617,12 +640,13 @@ TEST_F(LogTest, ClearEofSingleBlock) {
  ASSERT_TRUE(IsEOF());
 }

-TEST_F(LogTest, ClearEofMultiBlock) {
+TEST_P(LogTest, ClearEofMultiBlock) {
  size_t num_full_blocks = 5;
-  size_t n = (kBlockSize - kHeaderSize) * num_full_blocks + 25;
+  int header_size = GetParam() ? kRecyclableHeaderSize : kHeaderSize;
+  size_t n = (kBlockSize - header_size) * num_full_blocks + 25;
  Write(BigString("foo", n));
  Write(BigString("bar", n));
-  ForceEOF(n + num_full_blocks * kHeaderSize + 10);
+  ForceEOF(n + num_full_blocks * header_size + header_size + 3);
  ASSERT_EQ(BigString("foo", n), Read());
  ASSERT_TRUE(IsEOF());
  UnmarkEOF();
@@ -634,7 +658,7 @@ TEST_F(LogTest, ClearEofMultiBlock) {
  ASSERT_TRUE(IsEOF());
 }

-TEST_F(LogTest, ClearEofError) {
+TEST_P(LogTest, ClearEofError) {
  // If an error occurs during Read() in UnmarkEOF(), the records contained
  // in the buffer should be returned on subsequent calls of ReadRecord()
  // until no more full records are left, whereafter ReadRecord() should return
@@ -652,7 +676,7 @@ TEST_F(LogTest, ClearEofError) {
  ASSERT_EQ("EOF", Read());
 }

-TEST_F(LogTest, ClearEofError2) {
+TEST_P(LogTest, ClearEofError2) {
  Write("foo");
  Write("bar");
  UnmarkEOF();
@@ -666,6 +690,8 @@ TEST_F(LogTest, ClearEofError2) {
  ASSERT_EQ("OK", MatchError("read error"));
 }

+INSTANTIATE_TEST_CASE_P(bool, LogTest, ::testing::Values(0, 2));
+
 }  // namespace log
 }  // namespace rocksdb

@@ -18,8 +18,12 @@
 namespace rocksdb {
 namespace log {

-Writer::Writer(unique_ptr<WritableFileWriter>&& dest)
-    : dest_(std::move(dest)), block_offset_(0) {
+Writer::Writer(unique_ptr<WritableFileWriter>&& dest,
+               uint64_t log_number, bool recycle_log_files)
+    : dest_(std::move(dest)),
+      block_offset_(0),
+      log_number_(log_number),
+      recycle_log_files_(recycle_log_files) {
  for (int i = 0; i <= kMaxRecordType; i++) {
    char t = static_cast<char>(i);
    type_crc_[i] = crc32c::Value(&t, 1);
@@ -33,40 +37,46 @@ Status Writer::AddRecord(const Slice& slice) {
  const char* ptr = slice.data();
  size_t left = slice.size();

+  // Header size varies depending on whether we are recycling or not.
+  const int header_size =
+      recycle_log_files_ ? kRecyclableHeaderSize : kHeaderSize;
+
  // Fragment the record if necessary and emit it.  Note that if slice
  // is empty, we still want to iterate once to emit a single
  // zero-length record
  Status s;
  bool begin = true;
  do {
-    const int leftover = kBlockSize - block_offset_;
+    const int64_t leftover = kBlockSize - block_offset_;
    assert(leftover >= 0);
-    if (leftover < kHeaderSize) {
+    if (leftover < header_size) {
      // Switch to a new block
      if (leftover > 0) {
-        // Fill the trailer (literal below relies on kHeaderSize being 7)
-        assert(kHeaderSize == 7);
-        dest_->Append(Slice("\x00\x00\x00\x00\x00\x00", leftover));
+        // Fill the trailer (literal below relies on kHeaderSize and
+        // kRecyclableHeaderSize being <= 11)
+        assert(header_size <= 11);
+        dest_->Append(
+            Slice("\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", leftover));
      }
      block_offset_ = 0;
    }

-    // Invariant: we never leave < kHeaderSize bytes in a block.
-    assert(static_cast<int>(kBlockSize) - block_offset_ >= kHeaderSize);
+    // Invariant: we never leave < header_size bytes in a block.
+    assert(static_cast<int64_t>(kBlockSize - block_offset_) >= header_size);

-    const size_t avail = kBlockSize - block_offset_ - kHeaderSize;
+    const size_t avail = kBlockSize - block_offset_ - header_size;
    const size_t fragment_length = (left < avail) ? left : avail;

    RecordType type;
    const bool end = (left == fragment_length);
    if (begin && end) {
-      type = kFullType;
+      type = recycle_log_files_ ? kRecyclableFullType : kFullType;
    } else if (begin) {
-      type = kFirstType;
+      type = recycle_log_files_ ? kRecyclableFirstType : kFirstType;
    } else if (end) {
-      type = kLastType;
+      type = recycle_log_files_ ? kRecyclableLastType : kLastType;
    } else {
-      type = kMiddleType;
+      type = recycle_log_files_ ? kRecyclableMiddleType : kMiddleType;
    }

    s = EmitPhysicalRecord(type, ptr, fragment_length);
@@ -79,28 +89,48 @@ Status Writer::AddRecord(const Slice& slice) {

 Status Writer::EmitPhysicalRecord(RecordType t, const char* ptr, size_t n) {
  assert(n <= 0xffff);  // Must fit in two bytes
-  assert(block_offset_ + kHeaderSize + n <= kBlockSize);
+
+  size_t header_size;
+  char buf[kRecyclableHeaderSize];

  // Format the header
-  char buf[kHeaderSize];
  buf[4] = static_cast<char>(n & 0xff);
  buf[5] = static_cast<char>(n >> 8);
  buf[6] = static_cast<char>(t);

+  uint32_t crc = type_crc_[t];
+  if (t < kRecyclableFullType) {
+    // Legacy record format
+    assert(block_offset_ + kHeaderSize + n <= kBlockSize);
+    header_size = kHeaderSize;
+  } else {
+    // Recyclable record format
+    assert(block_offset_ + kRecyclableHeaderSize + n <= kBlockSize);
+    header_size = kRecyclableHeaderSize;
+
+    // Only encode low 32-bits of the 64-bit log number.  This means
+    // we will fail to detect an old record if we recycled a log from
+    // ~4 billion logs ago, but that is effectively impossible, and
+    // even if it were we'dbe far more likely to see a false positive
+    // on the 32-bit CRC.
+    EncodeFixed32(buf + 7, static_cast<uint32_t>(log_number_));
+    crc = crc32c::Extend(crc, buf + 7, 4);
+  }
+
  // Compute the crc of the record type and the payload.
-  uint32_t crc = crc32c::Extend(type_crc_[t], ptr, n);
-  crc = crc32c::Mask(crc);                 // Adjust for storage
+  crc = crc32c::Extend(crc, ptr, n);
+  crc = crc32c::Mask(crc);  // Adjust for storage
  EncodeFixed32(buf, crc);

  // Write the header and the payload
-  Status s = dest_->Append(Slice(buf, kHeaderSize));
+  Status s = dest_->Append(Slice(buf, header_size));
  if (s.ok()) {
    s = dest_->Append(Slice(ptr, n));
    if (s.ok()) {
      s = dest_->Flush();
    }
  }
-  block_offset_ += kHeaderSize + n;
+  block_offset_ += header_size + n;
  return s;
 }

@@ -43,7 +43,7 @@ namespace log {
 * Data is written out in kBlockSize chunks. If next record does not fit
 * into the space left, the leftover space will be padded with \0.
 *
- * Record format:
+ * Legacy record format:
 *
 * +---------+-----------+-----------+--- ... ---+
 * |CRC (4B) | Size (2B) | Type (1B) | Payload   |
@@ -57,13 +57,23 @@ namespace log {
 *        blocks that are larger than kBlockSize
 * Payload = Byte stream as long as specified by the payload size
 *
+ * Recyclable record format:
+ *
+ * +---------+-----------+-----------+----------------+--- ... ---+
+ * |CRC (4B) | Size (2B) | Type (1B) | Log number (4B)| Payload   |
+ * +---------+-----------+-----------+----------------+--- ... ---+
+ *
+ * Same as above, with the addition of
+ * Log number = 32bit log file number, so that we can distinguish between
+ * records written by the most recent log writer vs a previous one.
 */
 class Writer {
 public:
  // Create a writer that will append data to "*dest".
  // "*dest" must be initially empty.
  // "*dest" must remain live while this Writer is in use.
-  explicit Writer(unique_ptr<WritableFileWriter>&& dest);
+  explicit Writer(unique_ptr<WritableFileWriter>&& dest,
+                  uint64_t log_number, bool recycle_log_files);
  ~Writer();

  Status AddRecord(const Slice& slice);
@@ -73,7 +83,9 @@ class Writer {

 private:
  unique_ptr<WritableFileWriter> dest_;
-  int block_offset_;       // Current offset in block
+  size_t block_offset_;       // Current offset in block
+  uint64_t log_number_;
+  bool recycle_log_files_;

  // crc32c values for all supported record types.  These are
  // pre-computed to reduce the overhead of computing the crc of the
@@ -21,6 +21,7 @@
 #include "rocksdb/iterator.h"
 #include "rocksdb/merge_operator.h"
 #include "rocksdb/slice_transform.h"
+#include "table/internal_iterator.h"
 #include "table/merger.h"
 #include "util/arena.h"
 #include "util/coding.h"
@@ -59,7 +60,7 @@ MemTable::MemTable(const InternalKeyComparator& cmp,
      moptions_(ioptions, mutable_cf_options),
      refs_(0),
      kArenaBlockSize(OptimizeBlockSize(moptions_.arena_block_size)),
-      arena_(moptions_.arena_block_size),
+      arena_(moptions_.arena_block_size, 0),
      allocator_(&arena_, write_buffer),
      table_(ioptions.memtable_factory->CreateMemTableRep(
          comparator_, &allocator_, ioptions.prefix_extractor,
@@ -77,12 +78,12 @@ MemTable::MemTable(const InternalKeyComparator& cmp,
                 ? moptions_.inplace_update_num_locks
                 : 0),
      prefix_extractor_(ioptions.prefix_extractor),
-      should_flush_(ShouldFlushNow()),
-      flush_scheduled_(false),
+      flush_state_(FLUSH_NOT_REQUESTED),
      env_(ioptions.env) {
-  // if should_flush_ == true without an entry inserted, something must have
-  // gone wrong already.
-  assert(!should_flush_);
+  UpdateFlushState();
+  // something went wrong if we need to flush before inserting anything
+  assert(!ShouldScheduleFlush());
+
  if (prefix_extractor_ && moptions_.memtable_prefix_bloom_bits > 0) {
    prefix_bloom_.reset(new DynamicBloom(
        &allocator_,
@@ -166,6 +167,17 @@ bool MemTable::ShouldFlushNow() const {
  return arena_.AllocatedAndUnused() < kArenaBlockSize / 4;
 }

+void MemTable::UpdateFlushState() {
+  auto state = flush_state_.load(std::memory_order_relaxed);
+  if (state == FLUSH_NOT_REQUESTED && ShouldFlushNow()) {
+    // ignore CAS failure, because that means somebody else requested
+    // a flush
+    flush_state_.compare_exchange_strong(state, FLUSH_REQUESTED,
+                                         std::memory_order_relaxed,
+                                         std::memory_order_relaxed);
+  }
+}
+
 int MemTable::KeyComparator::operator()(const char* prefix_len_key1,
                                        const char* prefix_len_key2) const {
  // Internal keys are encoded as length-prefixed strings.
@@ -202,7 +214,7 @@ const char* EncodeKey(std::string* scratch, const Slice& target) {
  return scratch->data();
 }

-class MemTableIterator: public Iterator {
+class MemTableIterator : public InternalIterator {
 public:
  MemTableIterator(
      const MemTable& mem, const ReadOptions& read_options, Arena* arena)
@@ -273,6 +285,21 @@ class MemTableIterator: public Iterator {

  virtual Status status() const override { return Status::OK(); }

+  virtual Status PinData() override {
+    // memtable data is always pinned
+    return Status::OK();
+  }
+
+  virtual Status ReleasePinnedData() override {
+    // memtable data is always pinned
+    return Status::OK();
+  }
+
+  virtual bool IsKeyPinned() const override {
+    // memtable data is always pinned
+    return true;
+  }
+
 private:
  DynamicBloom* bloom_;
  const SliceTransform* const prefix_extractor_;
@@ -285,7 +312,8 @@ class MemTableIterator: public Iterator {
  void operator=(const MemTableIterator&);
 };

-Iterator* MemTable::NewIterator(const ReadOptions& read_options, Arena* arena) {
+InternalIterator* MemTable::NewIterator(const ReadOptions& read_options,
+                                        Arena* arena) {
  assert(arena != nullptr);
  auto mem = arena->AllocateAligned(sizeof(MemTableIterator));
  return new (mem) MemTableIterator(*this, read_options, arena);
@@ -318,7 +346,7 @@ uint64_t MemTable::ApproximateSize(const Slice& start_ikey,

 void MemTable::Add(SequenceNumber s, ValueType type,
                   const Slice& key, /* user key */
-                   const Slice& value) {
+                   const Slice& value, bool allow_concurrent) {
  // Format of an entry is concatenation of:
  //  key_size     : varint32 of internal_key.size()
  //  key bytes    : char[internal_key.size()]
@@ -332,7 +360,7 @@ void MemTable::Add(SequenceNumber s, ValueType type,
                               val_size;
  char* buf = nullptr;
  KeyHandle handle = table_->Allocate(encoded_len, &buf);
-  assert(buf != nullptr);
+
  char* p = EncodeVarint32(buf, internal_key_size);
  memcpy(p, key.data(), key_size);
  p += key_size;
@@ -342,32 +370,64 @@ void MemTable::Add(SequenceNumber s, ValueType type,
  p = EncodeVarint32(p, val_size);
  memcpy(p, value.data(), val_size);
  assert((unsigned)(p + val_size - buf) == (unsigned)encoded_len);
-  table_->Insert(handle);
-  num_entries_.store(num_entries_.load(std::memory_order_relaxed) + 1,
+  if (!allow_concurrent) {
+    table_->Insert(handle);
+
+    // this is a bit ugly, but is the way to avoid locked instructions
+    // when incrementing an atomic
+    num_entries_.store(num_entries_.load(std::memory_order_relaxed) + 1,
+                       std::memory_order_relaxed);
+    data_size_.store(data_size_.load(std::memory_order_relaxed) + encoded_len,
                     std::memory_order_relaxed);
-  data_size_.store(data_size_.load(std::memory_order_relaxed) + encoded_len,
-                   std::memory_order_relaxed);
-  if (type == kTypeDeletion) {
-    num_deletes_++;
-  }
-
-  if (prefix_bloom_) {
-    assert(prefix_extractor_);
-    prefix_bloom_->Add(prefix_extractor_->Transform(key));
-  }
-
-  // The first sequence number inserted into the memtable
-  assert(first_seqno_ == 0 || s > first_seqno_);
-  if (first_seqno_ == 0) {
-    first_seqno_ = s;
-
-    if (earliest_seqno_ == kMaxSequenceNumber) {
-      earliest_seqno_ = first_seqno_;
+    if (type == kTypeDeletion) {
+      num_deletes_.store(num_deletes_.load(std::memory_order_relaxed) + 1,
+                         std::memory_order_relaxed);
+    }
+
+    if (prefix_bloom_) {
+      assert(prefix_extractor_);
+      prefix_bloom_->Add(prefix_extractor_->Transform(key));
+    }
+
+    // The first sequence number inserted into the memtable
+    assert(first_seqno_ == 0 || s > first_seqno_);
+    if (first_seqno_ == 0) {
+      first_seqno_.store(s, std::memory_order_relaxed);
+
+      if (earliest_seqno_ == kMaxSequenceNumber) {
+        earliest_seqno_.store(GetFirstSequenceNumber(),
+                              std::memory_order_relaxed);
+      }
+      assert(first_seqno_.load() >= earliest_seqno_.load());
+    }
+  } else {
+    table_->InsertConcurrently(handle);
+
+    num_entries_.fetch_add(1, std::memory_order_relaxed);
+    data_size_.fetch_add(encoded_len, std::memory_order_relaxed);
+    if (type == kTypeDeletion) {
+      num_deletes_.fetch_add(1, std::memory_order_relaxed);
+    }
+
+    if (prefix_bloom_) {
+      assert(prefix_extractor_);
+      prefix_bloom_->AddConcurrently(prefix_extractor_->Transform(key));
+    }
+
+    // atomically update first_seqno_ and earliest_seqno_.
+    uint64_t cur_seq_num = first_seqno_.load(std::memory_order_relaxed);
+    while ((cur_seq_num == 0 || s < cur_seq_num) &&
+           !first_seqno_.compare_exchange_weak(cur_seq_num, s)) {
+    }
+    uint64_t cur_earliest_seqno =
+        earliest_seqno_.load(std::memory_order_relaxed);
+    while (
+        (cur_earliest_seqno == kMaxSequenceNumber || s < cur_earliest_seqno) &&
+        !first_seqno_.compare_exchange_weak(cur_earliest_seqno, s)) {
    }
-    assert(first_seqno_ >= earliest_seqno_);
  }

-  should_flush_ = ShouldFlushNow();
+  UpdateFlushState();
 }

 // Callback from MemTable::Get()
@@ -440,7 +500,7 @@ static bool SaveValue(void* arg, const char* entry) {
            *(s->status) =
                Status::Corruption("Error: Could not perform merge.");
          }
-        } else {
+        } else if (s->value != nullptr) {
          s->value->assign(v.data(), v.size());
        }
        if (s->inplace_update_support) {
@@ -668,16 +728,16 @@ bool MemTable::UpdateCallback(SequenceNumber seq,
              }
            }
            RecordTick(moptions_.statistics, NUMBER_KEYS_UPDATED);
-            should_flush_ = ShouldFlushNow();
+            UpdateFlushState();
            return true;
          } else if (status == UpdateStatus::UPDATED) {
            Add(seq, kTypeValue, key, Slice(str_value));
            RecordTick(moptions_.statistics, NUMBER_KEYS_WRITTEN);
-            should_flush_ = ShouldFlushNow();
+            UpdateFlushState();
            return true;
          } else if (status == UpdateStatus::UPDATE_FAILED) {
            // No action required. Return.
-            should_flush_ = ShouldFlushNow();
+            UpdateFlushState();
            return true;
          }
        }
@@ -8,10 +8,11 @@
 // found in the LICENSE file. See the AUTHORS file for names of contributors.

 #pragma once
-#include <string>
-#include <memory>
-#include <functional>
+#include <atomic>
 #include <deque>
+#include <functional>
+#include <memory>
+#include <string>
 #include <vector>
 #include "db/dbformat.h"
 #include "db/skiplist.h"
@@ -21,8 +22,9 @@
 #include "rocksdb/memtablerep.h"
 #include "rocksdb/immutable_options.h"
 #include "db/memtable_allocator.h"
-#include "util/arena.h"
+#include "util/concurrent_arena.h"
 #include "util/dynamic_bloom.h"
+#include "util/instrumented_mutex.h"
 #include "util/mutable_cf_options.h"

 namespace rocksdb {
@@ -31,6 +33,7 @@ class Mutex;
 class MemTableIterator;
 class MergeContext;
 class WriteBuffer;
+class InternalIterator;

 struct MemTableOptions {
  explicit MemTableOptions(
@@ -123,10 +126,17 @@ class MemTable {
  // This method heuristically determines if the memtable should continue to
  // host more data.
  bool ShouldScheduleFlush() const {
-    return flush_scheduled_ == false && should_flush_;
+    return flush_state_.load(std::memory_order_relaxed) == FLUSH_REQUESTED;
  }

-  void MarkFlushScheduled() { flush_scheduled_ = true; }
+  // Returns true if a flush should be scheduled and the caller should
+  // be the one to schedule it
+  bool MarkFlushScheduled() {
+    auto before = FLUSH_REQUESTED;
+    return flush_state_.compare_exchange_strong(before, FLUSH_SCHEDULED,
+                                                std::memory_order_relaxed,
+                                                std::memory_order_relaxed);
+  }

  // Return an iterator that yields the contents of the memtable.
  //
@@ -140,17 +150,16 @@ class MemTable {
  // arena: If not null, the arena needs to be used to allocate the Iterator.
  //        Calling ~Iterator of the iterator will destroy all the states but
  //        those allocated in arena.
-  Iterator* NewIterator(const ReadOptions& read_options, Arena* arena);
+  InternalIterator* NewIterator(const ReadOptions& read_options, Arena* arena);

  // Add an entry into memtable that maps key to value at the
  // specified sequence number and with the specified type.
  // Typically value will be empty if type==kTypeDeletion.
  //
-  // REQUIRES: external synchronization to prevent simultaneous
-  // operations on the same MemTable.
-  void Add(SequenceNumber seq, ValueType type,
-           const Slice& key,
-           const Slice& value);
+  // REQUIRES: if allow_concurrent = false, external synchronization to prevent
+  // simultaneous operations on the same MemTable.
+  void Add(SequenceNumber seq, ValueType type, const Slice& key,
+           const Slice& value, bool allow_concurrent = false);

  // If memtable contains a value for key, store it in *value and return true.
  // If memtable contains a deletion for key, store a NotFound() error
@@ -188,7 +197,7 @@ class MemTable {
              const Slice& key,
              const Slice& value);

-  // If prev_value for key exits, attempts to update it inplace.
+  // If prev_value for key exists, attempts to update it inplace.
  // else returns false
  // Pseudocode
  //   if key exists in current memtable && prev_value is of type kTypeValue
@@ -219,7 +228,9 @@ class MemTable {
  // Get total number of deletes in the mem table.
  // REQUIRES: external synchronization to prevent simultaneous
  // operations on the same MemTable (unless this Memtable is immutable).
-  uint64_t num_deletes() const { return num_deletes_; }
+  uint64_t num_deletes() const {
+    return num_deletes_.load(std::memory_order_relaxed);
+  }

  // Returns the edits area that is needed for flushing the memtable
  VersionEdit* GetEdits() { return &edit_; }
@@ -233,7 +244,9 @@ class MemTable {
  // into the memtable.
  // REQUIRES: external synchronization to prevent simultaneous
  // operations on the same MemTable (unless this Memtable is immutable).
-  SequenceNumber GetFirstSequenceNumber() { return first_seqno_; }
+  SequenceNumber GetFirstSequenceNumber() {
+    return first_seqno_.load(std::memory_order_relaxed);
+  }

  // Returns the sequence number that is guaranteed to be smaller than or equal
  // to the sequence number of any key that could be inserted into this
@@ -242,7 +255,9 @@ class MemTable {
  //
  // If the earliest sequence number could not be determined,
  // kMaxSequenceNumber will be returned.
-  SequenceNumber GetEarliestSequenceNumber() { return earliest_seqno_; }
+  SequenceNumber GetEarliestSequenceNumber() {
+    return earliest_seqno_.load(std::memory_order_relaxed);
+  }

  // Returns the next active logfile number when this memtable is about to
  // be flushed to storage
@@ -289,8 +304,7 @@ class MemTable {
  const MemTableOptions* GetMemTableOptions() const { return &moptions_; }

 private:
-  // Dynamically check if we can add more incoming entries
-  bool ShouldFlushNow() const;
+  enum FlushStateEnum { FLUSH_NOT_REQUESTED, FLUSH_REQUESTED, FLUSH_SCHEDULED };

  friend class MemTableIterator;
  friend class MemTableBackwardIterator;
@@ -300,14 +314,14 @@ class MemTable {
  const MemTableOptions moptions_;
  int refs_;
  const size_t kArenaBlockSize;
-  Arena arena_;
+  ConcurrentArena arena_;
  MemTableAllocator allocator_;
  unique_ptr<MemTableRep> table_;

  // Total data size of all data inserted
  std::atomic<uint64_t> data_size_;
  std::atomic<uint64_t> num_entries_;
-  uint64_t num_deletes_;
+  std::atomic<uint64_t> num_deletes_;

  // These are used to manage memtable flushes to storage
  bool flush_in_progress_; // started the flush
@@ -319,11 +333,11 @@ class MemTable {
  VersionEdit edit_;

  // The sequence number of the kv that was inserted first
-  SequenceNumber first_seqno_;
+  std::atomic<SequenceNumber> first_seqno_;

  // The db sequence number at the time of creation or kMaxSequenceNumber
  // if not set.
-  SequenceNumber earliest_seqno_;
+  std::atomic<SequenceNumber> earliest_seqno_;

  // The log files earlier than this number can be deleted.
  uint64_t mem_next_logfile_number_;
@@ -331,19 +345,22 @@ class MemTable {
  // rw locks for inplace updates
  std::vector<port::RWMutex> locks_;

-  // No copying allowed
-  MemTable(const MemTable&);
-  void operator=(const MemTable&);
-
  const SliceTransform* const prefix_extractor_;
  std::unique_ptr<DynamicBloom> prefix_bloom_;

-  // a flag indicating if a memtable has met the criteria to flush
-  bool should_flush_;
+  std::atomic<FlushStateEnum> flush_state_;

-  // a flag indicating if flush has been scheduled
-  bool flush_scheduled_;
  Env* env_;
+
+  // Returns a heuristic flush decision
+  bool ShouldFlushNow() const;
+
+  // Updates flush_state_ using ShouldFlushNow()
+  void UpdateFlushState();
+
+  // No copying allowed
+  MemTable(const MemTable&);
+  MemTable& operator=(const MemTable&);
 };

 extern const char* EncodeKey(std::string* scratch, const Slice& target);
@@ -7,46 +7,42 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file. See the AUTHORS file for names of contributors.

-#include <assert.h>
-
 #include "db/memtable_allocator.h"
+
+#include <assert.h>
 #include "db/writebuffer.h"
 #include "util/arena.h"

 namespace rocksdb {

-MemTableAllocator::MemTableAllocator(Arena* arena, WriteBuffer* write_buffer)
-    : arena_(arena), write_buffer_(write_buffer), bytes_allocated_(0) {
-}
+MemTableAllocator::MemTableAllocator(Allocator* allocator,
+                                     WriteBuffer* write_buffer)
+    : allocator_(allocator), write_buffer_(write_buffer), bytes_allocated_(0) {}

-MemTableAllocator::~MemTableAllocator() {
-  DoneAllocating();
-}
+MemTableAllocator::~MemTableAllocator() { DoneAllocating(); }

 char* MemTableAllocator::Allocate(size_t bytes) {
  assert(write_buffer_ != nullptr);
-  bytes_allocated_ += bytes;
+  bytes_allocated_.fetch_add(bytes, std::memory_order_relaxed);
  write_buffer_->ReserveMem(bytes);
-  return arena_->Allocate(bytes);
+  return allocator_->Allocate(bytes);
 }

 char* MemTableAllocator::AllocateAligned(size_t bytes, size_t huge_page_size,
                                         Logger* logger) {
  assert(write_buffer_ != nullptr);
-  bytes_allocated_ += bytes;
+  bytes_allocated_.fetch_add(bytes, std::memory_order_relaxed);
  write_buffer_->ReserveMem(bytes);
-  return arena_->AllocateAligned(bytes, huge_page_size, logger);
+  return allocator_->AllocateAligned(bytes, huge_page_size, logger);
 }

 void MemTableAllocator::DoneAllocating() {
  if (write_buffer_ != nullptr) {
-    write_buffer_->FreeMem(bytes_allocated_);
+    write_buffer_->FreeMem(bytes_allocated_.load(std::memory_order_relaxed));
    write_buffer_ = nullptr;
  }
 }

-size_t MemTableAllocator::BlockSize() const {
-  return arena_->BlockSize();
-}
+size_t MemTableAllocator::BlockSize() const { return allocator_->BlockSize(); }

 }  // namespace rocksdb
@@ -11,17 +11,18 @@
 // to WriteBuffer so we can track and enforce overall write buffer limits.

 #pragma once
+
+#include <atomic>
 #include "util/allocator.h"

 namespace rocksdb {

-class Arena;
 class Logger;
 class WriteBuffer;

 class MemTableAllocator : public Allocator {
 public:
-  explicit MemTableAllocator(Arena* arena, WriteBuffer* write_buffer);
+  explicit MemTableAllocator(Allocator* allocator, WriteBuffer* write_buffer);
  ~MemTableAllocator();

  // Allocator interface
@@ -35,9 +36,9 @@ class MemTableAllocator : public Allocator {
  void DoneAllocating();

 private:
-  Arena* arena_;
+  Allocator* allocator_;
  WriteBuffer* write_buffer_;
-  size_t bytes_allocated_;
+  std::atomic<size_t> bytes_allocated_;

  // No copying allowed
  MemTableAllocator(const MemTableAllocator&);
@@ -138,9 +138,9 @@ bool MemTableListVersion::GetFromList(std::list<MemTable*>* list,
  return false;
 }

-void MemTableListVersion::AddIterators(const ReadOptions& options,
-                                       std::vector<Iterator*>* iterator_list,
-                                       Arena* arena) {
+void MemTableListVersion::AddIterators(
+    const ReadOptions& options, std::vector<InternalIterator*>* iterator_list,
+    Arena* arena) {
  for (auto& m : memlist_) {
    iterator_list->push_back(m->NewIterator(options, arena));
  }
@@ -74,7 +74,8 @@ class MemTableListVersion {
  }

  void AddIterators(const ReadOptions& options,
-                    std::vector<Iterator*>* iterator_list, Arena* arena);
+                    std::vector<InternalIterator*>* iterator_list,
+                    Arena* arena);

  void AddIterators(const ReadOptions& options,
                    MergeIteratorBuilder* merge_iter_builder);
@@ -132,8 +132,6 @@ DEFINE_int64(seed, 0,
             "Seed base for random number generators. "
             "When 0 it is deterministic.");

-static rocksdb::Env* FLAGS_env = rocksdb::Env::Default();
-
 namespace rocksdb {

 namespace {
@@ -592,6 +590,7 @@ int main(int argc, char** argv) {
  std::unique_ptr<rocksdb::MemTableRepFactory> factory;
  if (FLAGS_memtablerep == "skiplist") {
    factory.reset(new rocksdb::SkipListFactory);
+#ifndef ROCKSDB_LITE
  } else if (FLAGS_memtablerep == "vector") {
    factory.reset(new rocksdb::VectorRepFactory);
  } else if (FLAGS_memtablerep == "hashskiplist") {
@@ -613,6 +612,7 @@ int main(int argc, char** argv) {
        static_cast<uint32_t>(FLAGS_hash_function_count)));
    options.prefix_extractor.reset(
        rocksdb::NewFixedPrefixTransform(FLAGS_prefix_length));
+#endif  // ROCKSDB_LITE
  } else {
    fprintf(stdout, "Unknown memtablerep: %s\n", FLAGS_memtablerep.c_str());
    exit(1);
@@ -12,6 +12,7 @@
 #include "rocksdb/comparator.h"
 #include "rocksdb/db.h"
 #include "rocksdb/merge_operator.h"
+#include "table/internal_iterator.h"
 #include "util/perf_context_imp.h"
 #include "util/statistics.h"

@@ -56,7 +57,8 @@ Status MergeHelper::TimedFullMerge(const Slice& key, const Slice* value,
 //       keys_ stores the list of keys encountered while merging.
 //       operands_ stores the list of merge operands encountered while merging.
 //       keys_[i] corresponds to operands_[i] for each i.
-Status MergeHelper::MergeUntil(Iterator* iter, const SequenceNumber stop_before,
+Status MergeHelper::MergeUntil(InternalIterator* iter,
+                               const SequenceNumber stop_before,
                               const bool at_bottom) {
  // Get a copy of the internal key, before it's invalidated by iter->Next()
  // Also maintain the list of merge operands seen.
@@ -22,6 +22,7 @@ class Iterator;
 class Logger;
 class MergeOperator;
 class Statistics;
+class InternalIterator;

 class MergeHelper {
 public:
@@ -82,7 +83,8 @@ class MergeHelper {
  //   with asserts removed).
  //
  // REQUIRED: The first key in the input is not corrupted.
-  Status MergeUntil(Iterator* iter, const SequenceNumber stop_before = 0,
+  Status MergeUntil(InternalIterator* iter,
+                    const SequenceNumber stop_before = 0,
                    const bool at_bottom = false);

  // Filters a merge operand using the compaction filter specified
@@ -20,7 +20,6 @@
 #include "utilities/merge_operators.h"
 #include "util/testharness.h"

-using namespace std;
 using namespace rocksdb;

 namespace {
@@ -76,7 +75,7 @@ class CountMergeOperator : public AssociativeMergeOperator {
 };

 namespace {
-std::shared_ptr<DB> OpenDb(const string& dbname, const bool ttl = false,
+std::shared_ptr<DB> OpenDb(const std::string& dbname, const bool ttl = false,
                           const size_t max_successive_merges = 0,
                           const uint32_t min_partial_merge_operands = 2) {
  DB* db;
@@ -90,7 +89,7 @@ std::shared_ptr<DB> OpenDb(const string& dbname, const bool ttl = false,
 // DBWithTTL is not supported in ROCKSDB_LITE
 #ifndef ROCKSDB_LITE
  if (ttl) {
-    cout << "Opening database with TTL\n";
+    std::cout << "Opening database with TTL\n";
    DBWithTTL* db_with_ttl;
    s = DBWithTTL::Open(options, dbname, &db_with_ttl);
    db = db_with_ttl;
@@ -102,7 +101,7 @@ std::shared_ptr<DB> OpenDb(const string& dbname, const bool ttl = false,
  s = DB::Open(options, dbname, &db);
 #endif  // !ROCKSDB_LITE
  if (!s.ok()) {
-    cerr << s.ToString() << endl;
+    std::cerr << s.ToString() << std::endl;
    assert(false);
  }
  return std::shared_ptr<DB>(db);
@@ -142,7 +141,7 @@ class Counters {
  // if the underlying level db operation failed.

  // mapped to a levedb Put
-  bool set(const string& key, uint64_t value) {
+  bool set(const std::string& key, uint64_t value) {
    // just treat the internal rep of int64 as the string
    Slice slice((char *)&value, sizeof(value));
    auto s = db_->Put(put_option_, key, slice);
@@ -150,26 +149,26 @@ class Counters {
    if (s.ok()) {
      return true;
    } else {
-      cerr << s.ToString() << endl;
+      std::cerr << s.ToString() << std::endl;
      return false;
    }
  }

  // mapped to a rocksdb Delete
-  bool remove(const string& key) {
+  bool remove(const std::string& key) {
    auto s = db_->Delete(delete_option_, key);

    if (s.ok()) {
      return true;
    } else {
-      cerr << s.ToString() << std::endl;
+      std::cerr << s.ToString() << std::endl;
      return false;
    }
  }

  // mapped to a rocksdb Get
-  bool get(const string& key, uint64_t *value) {
-    string str;
+  bool get(const std::string& key, uint64_t* value) {
+    std::string str;
    auto s = db_->Get(get_option_, key, &str);

    if (s.IsNotFound()) {
@@ -179,35 +178,33 @@ class Counters {
    } else if (s.ok()) {
      // deserialization
      if (str.size() != sizeof(uint64_t)) {
-        cerr << "value corruption\n";
+        std::cerr << "value corruption\n";
        return false;
      }
      *value = DecodeFixed64(&str[0]);
      return true;
    } else {
-      cerr << s.ToString() << std::endl;
+      std::cerr << s.ToString() << std::endl;
      return false;
    }
  }

  // 'add' is implemented as get -> modify -> set
  // An alternative is a single merge operation, see MergeBasedCounters
-  virtual bool add(const string& key, uint64_t value) {
+  virtual bool add(const std::string& key, uint64_t value) {
    uint64_t base = default_;
    return get(key, &base) && set(key, base + value);
  }


  // convenience functions for testing
-  void assert_set(const string& key, uint64_t value) {
+  void assert_set(const std::string& key, uint64_t value) {
    assert(set(key, value));
  }

-  void assert_remove(const string& key) {
-    assert(remove(key));
-  }
+  void assert_remove(const std::string& key) { assert(remove(key)); }

-  uint64_t assert_get(const string& key) {
+  uint64_t assert_get(const std::string& key) {
    uint64_t value = default_;
    int result = get(key, &value);
    assert(result);
@@ -215,7 +212,7 @@ class Counters {
    return value;
  }

-  void assert_add(const string& key, uint64_t value) {
+  void assert_add(const std::string& key, uint64_t value) {
    int result = add(key, value);
    assert(result);
    if (result == 0) exit(1); // Disable unused variable warning.
@@ -234,7 +231,7 @@ class MergeBasedCounters : public Counters {
  }

  // mapped to a rocksdb Merge operation
-  virtual bool add(const string& key, uint64_t value) override {
+  virtual bool add(const std::string& key, uint64_t value) override {
    char encoded[sizeof(uint64_t)];
    EncodeFixed64(encoded, value);
    Slice slice(encoded, sizeof(uint64_t));
@@ -243,7 +240,7 @@ class MergeBasedCounters : public Counters {
    if (s.ok()) {
      return true;
    } else {
-      cerr << s.ToString() << endl;
+      std::cerr << s.ToString() << std::endl;
      return false;
    }
  }
@@ -254,7 +251,7 @@ void dumpDb(DB* db) {
  auto it = unique_ptr<Iterator>(db->NewIterator(ReadOptions()));
  for (it->SeekToFirst(); it->Valid(); it->Next()) {
    uint64_t value = DecodeFixed64(it->value().data());
-    cout << it->key().ToString() << ": "  << value << endl;
+    std::cout << it->key().ToString() << ": " << value << std::endl;
  }
  assert(it->status().ok());  // Check for any errors found during the scan
 }
@@ -302,9 +299,9 @@ void testCounters(Counters& counters, DB* db, bool test_compaction) {
  if (test_compaction) {
    db->Flush(o);

-    cout << "Compaction started ...\n";
+    std::cout << "Compaction started ...\n";
    db->CompactRange(CompactRangeOptions(), nullptr, nullptr);
-    cout << "Compaction ended\n";
+    std::cout << "Compaction ended\n";

    dumpDb(db);

@@ -400,7 +397,7 @@ void testSingleBatchSuccessiveMerge(DB* db, size_t max_num_merges,

  // Get the value
  resetNumMergeOperatorCalls();
-  string get_value_str;
+  std::string get_value_str;
  {
    Status s = db->Get(ReadOptions(), key, &get_value_str);
    assert(s.ok());
@@ -412,24 +409,24 @@ void testSingleBatchSuccessiveMerge(DB* db, size_t max_num_merges,
            static_cast<size_t>((num_merges % (max_num_merges + 1))));
 }

-void runTest(int argc, const string& dbname, const bool use_ttl = false) {
+void runTest(int argc, const std::string& dbname, const bool use_ttl = false) {
  bool compact = false;
  if (argc > 1) {
    compact = true;
-    cout << "Turn on Compaction\n";
+    std::cout << "Turn on Compaction\n";
  }

  {
    auto db = OpenDb(dbname, use_ttl);

    {
-      cout << "Test read-modify-write counters... \n";
+      std::cout << "Test read-modify-write counters... \n";
      Counters counters(db, 0);
      testCounters(counters, db.get(), true);
    }

    {
-      cout << "Test merge-based counters... \n";
+      std::cout << "Test merge-based counters... \n";
      MergeBasedCounters counters(db, 0);
      testCounters(counters, db.get(), compact);
    }
@@ -438,7 +435,7 @@ void runTest(int argc, const string& dbname, const bool use_ttl = false) {
  DestroyDB(dbname, Options());

  {
-    cout << "Test merge in memtable... \n";
+    std::cout << "Test merge in memtable... \n";
    size_t max_merge = 5;
    auto db = OpenDb(dbname, use_ttl, max_merge);
    MergeBasedCounters counters(db, 0);
@@ -449,7 +446,7 @@ void runTest(int argc, const string& dbname, const bool use_ttl = false) {
  }

  {
-    cout << "Test Partial-Merge\n";
+    std::cout << "Test Partial-Merge\n";
    size_t max_merge = 100;
    for (uint32_t min_merge = 5; min_merge < 25; min_merge += 5) {
      for (uint32_t count = min_merge - 1; count <= min_merge + 1; count++) {
@@ -469,7 +466,7 @@ void runTest(int argc, const string& dbname, const bool use_ttl = false) {
  }

  {
-    cout << "Test merge-operator not set after reopen\n";
+    std::cout << "Test merge-operator not set after reopen\n";
    {
      auto db = OpenDb(dbname);
      MergeBasedCounters counters(db, 0);
@@ -489,7 +486,7 @@ void runTest(int argc, const string& dbname, const bool use_ttl = false) {

  /* Temporary remove this test
  {
-    cout << "Test merge-operator not set after reopen (recovery case)\n";
+    std::cout << "Test merge-operator not set after reopen (recovery case)\n";
    {
      auto db = OpenDb(dbname);
      MergeBasedCounters counters(db, 0);
@@ -0,0 +1,119 @@
+//  Copyright (c) 2015, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under the BSD-style license found in the
+//  LICENSE file in the root directory of this source tree. An additional grant
+//  of patent rights can be found in the PATENTS file in the same directory.
+
+#ifndef ROCKSDB_LITE
+#include <string>
+
+#include "db/db_impl.h"
+#include "db/db_test_util.h"
+#include "rocksdb/options.h"
+#include "rocksdb/table.h"
+#include "util/testharness.h"
+
+namespace rocksdb {
+class OptionsFileTest : public testing::Test {
+ public:
+  OptionsFileTest() : dbname_(test::TmpDir() + "/options_file_test") {}
+
+  std::string dbname_;
+};
+
+namespace {
+void UpdateOptionsFiles(DB* db,
+                        std::unordered_set<std::string>* filename_history,
+                        int* options_files_count) {
+  std::vector<std::string> filenames;
+  db->GetEnv()->GetChildren(db->GetName(), &filenames);
+  uint64_t number;
+  FileType type;
+  *options_files_count = 0;
+  for (auto filename : filenames) {
+    if (ParseFileName(filename, &number, &type) && type == kOptionsFile) {
+      filename_history->insert(filename);
+      (*options_files_count)++;
+    }
+  }
+}
+
+// Verify whether the current Options Files are the latest ones.
+void VerifyOptionsFileName(
+    DB* db, const std::unordered_set<std::string>& past_filenames) {
+  std::vector<std::string> filenames;
+  std::unordered_set<std::string> current_filenames;
+  db->GetEnv()->GetChildren(db->GetName(), &filenames);
+  uint64_t number;
+  FileType type;
+  for (auto filename : filenames) {
+    if (ParseFileName(filename, &number, &type) && type == kOptionsFile) {
+      current_filenames.insert(filename);
+    }
+  }
+  for (auto past_filename : past_filenames) {
+    if (current_filenames.find(past_filename) != current_filenames.end()) {
+      continue;
+    }
+    for (auto filename : current_filenames) {
+      ASSERT_GT(filename, past_filename);
+    }
+  }
+}
+}  // namespace
+
+TEST_F(OptionsFileTest, NumberOfOptionsFiles) {
+  const int kReopenCount = 20;
+  Options opt;
+  opt.create_if_missing = true;
+  DestroyDB(dbname_, opt);
+  std::unordered_set<std::string> filename_history;
+  DB* db;
+  for (int i = 0; i < kReopenCount; ++i) {
+    ASSERT_OK(DB::Open(opt, dbname_, &db));
+    int num_options_files = 0;
+    UpdateOptionsFiles(db, &filename_history, &num_options_files);
+    ASSERT_GT(num_options_files, 0);
+    ASSERT_LE(num_options_files, 2);
+    // Make sure we always keep the latest option files.
+    VerifyOptionsFileName(db, filename_history);
+    delete db;
+  }
+}
+
+TEST_F(OptionsFileTest, OptionsFileName) {
+  const uint64_t kOptionsFileNum = 12345;
+  uint64_t number;
+  FileType type;
+
+  auto options_file_name = OptionsFileName("", kOptionsFileNum);
+  ASSERT_TRUE(ParseFileName(options_file_name, &number, &type, nullptr));
+  ASSERT_EQ(type, kOptionsFile);
+  ASSERT_EQ(number, kOptionsFileNum);
+
+  const uint64_t kTempOptionsFileNum = 54352;
+  auto temp_options_file_name = TempOptionsFileName("", kTempOptionsFileNum);
+  ASSERT_TRUE(ParseFileName(temp_options_file_name, &number, &type, nullptr));
+  ASSERT_NE(temp_options_file_name.find(kTempFileNameSuffix),
+            std::string::npos);
+  ASSERT_EQ(type, kTempFile);
+  ASSERT_EQ(number, kTempOptionsFileNum);
+}
+}  // namespace rocksdb
+
+int main(int argc, char** argv) {
+#if !(defined NDEBUG) || !defined(OS_WIN)
+  ::testing::InitGoogleTest(&argc, argv);
+  return RUN_ALL_TESTS();
+#else
+  return 0;
+#endif  // !(defined NDEBUG) || !defined(OS_WIN)
+}
+#else
+
+#include <cstdio>
+
+int main(int argc, char** argv) {
+  printf("Skipped as Options file is not supported in RocksDBLite.\n");
+  return 0;
+}
+#endif  // !ROCKSDB_LITE
@@ -5,6 +5,7 @@
 //
 #include <algorithm>
 #include <iostream>
+#include <thread>
 #include <vector>

 #include "rocksdb/db.h"
@@ -444,6 +445,7 @@ void ProfileQueries(bool enabled_time = false) {
  }
 }

+#ifndef ROCKSDB_LITE
 TEST_F(PerfContextTest, KeyComparisonCount) {
  SetPerfLevel(kEnableCount);
  ProfileQueries();
@@ -454,6 +456,7 @@ TEST_F(PerfContextTest, KeyComparisonCount) {
  SetPerfLevel(kEnableTime);
  ProfileQueries(true);
 }
+#endif  // ROCKSDB_LITE

 // make perf_context_test
 // export ROCKSDB_TESTS=PerfContextTest.SeekKeyComparison
@@ -539,6 +542,49 @@ TEST_F(PerfContextTest, SeekKeyComparison) {
  }
 }

+TEST_F(PerfContextTest, DBMutexLockCounter) {
+  SetPerfLevel(kEnableTime);
+  int stats_code[] = {0, static_cast<int>(DB_MUTEX_WAIT_MICROS)};
+  for (int c = 0; c < 2; ++c) {
+    InstrumentedMutex mutex(nullptr, Env::Default(), stats_code[c]);
+    mutex.Lock();
+    std::thread child_thread([&] {
+      SetPerfLevel(kEnableTime);
+      perf_context.Reset();
+      ASSERT_EQ(perf_context.db_mutex_lock_nanos, 0);
+      mutex.Lock();
+      mutex.Unlock();
+      if (stats_code[c] == DB_MUTEX_WAIT_MICROS) {
+        // increment the counter only when it's a DB Mutex
+        ASSERT_GT(perf_context.db_mutex_lock_nanos, 0);
+      } else {
+        ASSERT_EQ(perf_context.db_mutex_lock_nanos, 0);
+      }
+    });
+    Env::Default()->SleepForMicroseconds(100);
+    mutex.Unlock();
+    child_thread.join();
+  }
+}
+
+TEST_F(PerfContextTest, FalseDBMutexWait) {
+  SetPerfLevel(kEnableTime);
+  int stats_code[] = {0, static_cast<int>(DB_MUTEX_WAIT_MICROS)};
+  for (int c = 0; c < 2; ++c) {
+    InstrumentedMutex mutex(nullptr, Env::Default(), stats_code[c]);
+    InstrumentedCondVar lock(&mutex);
+    perf_context.Reset();
+    mutex.Lock();
+    lock.TimedWait(100);
+    mutex.Unlock();
+    if (stats_code[c] == static_cast<int>(DB_MUTEX_WAIT_MICROS)) {
+      // increment the counter only when it's a DB Mutex
+      ASSERT_GT(perf_context.db_condition_wait_nanos, 0);
+    } else {
+      ASSERT_EQ(perf_context.db_condition_wait_nanos, 0);
+    }
+  }
+}
 }

 int main(int argc, char** argv) {
@@ -29,6 +29,7 @@
 #include "table/bloom_block.h"
 #include "table/table_builder.h"
 #include "table/plain_table_factory.h"
+#include "table/plain_table_key_coding.h"
 #include "table/plain_table_reader.h"
 #include "util/hash.h"
 #include "util/logging.h"
@@ -41,6 +42,59 @@
 using std::unique_ptr;

 namespace rocksdb {
+class PlainTableKeyDecoderTest : public testing::Test {};
+
+TEST_F(PlainTableKeyDecoderTest, ReadNonMmap) {
+  std::string tmp;
+  Random rnd(301);
+  const uint32_t kLength = 2222;
+  Slice contents = test::RandomString(&rnd, kLength, &tmp);
+  test::StringSource* string_source =
+      new test::StringSource(contents, 0, false);
+
+  unique_ptr<RandomAccessFileReader> file_reader(
+      test::GetRandomAccessFileReader(string_source));
+  unique_ptr<PlainTableReaderFileInfo> file_info(new PlainTableReaderFileInfo(
+      std::move(file_reader), EnvOptions(), kLength));
+
+  {
+    PlainTableFileReader reader(file_info.get());
+
+    const uint32_t kReadSize = 77;
+    for (uint32_t pos = 0; pos < kLength; pos += kReadSize) {
+      uint32_t read_size = std::min(kLength - pos, kReadSize);
+      Slice out;
+      ASSERT_TRUE(reader.Read(pos, read_size, &out));
+      ASSERT_EQ(0, out.compare(tmp.substr(pos, read_size)));
+    }
+
+    ASSERT_LT(uint32_t(string_source->total_reads()), kLength / kReadSize / 2);
+  }
+
+  std::vector<std::vector<std::pair<uint32_t, uint32_t>>> reads = {
+      {{600, 30}, {590, 30}, {600, 20}, {600, 40}},
+      {{800, 20}, {100, 20}, {500, 20}, {1500, 20}, {100, 20}, {80, 20}},
+      {{1000, 20}, {500, 20}, {1000, 50}},
+      {{1000, 20}, {500, 20}, {500, 20}},
+      {{1000, 20}, {500, 20}, {200, 20}, {500, 20}},
+      {{1000, 20}, {500, 20}, {200, 20}, {1000, 50}},
+      {{600, 500}, {610, 20}, {100, 20}},
+      {{500, 100}, {490, 100}, {550, 50}},
+  };
+
+  std::vector<int> num_file_reads = {2, 6, 2, 2, 4, 3, 2, 2};
+
+  for (size_t i = 0; i < reads.size(); i++) {
+    string_source->set_total_reads(0);
+    PlainTableFileReader reader(file_info.get());
+    for (auto p : reads[i]) {
+      Slice out;
+      ASSERT_TRUE(reader.Read(p.first, p.second, &out));
+      ASSERT_EQ(0, out.compare(tmp.substr(p.first, p.second)));
+    }
+    ASSERT_EQ(num_file_reads[i], string_source->total_reads());
+  }
+}

 class PlainTableDBTest : public testing::Test,
                         public testing::WithParamInterface<bool> {
@@ -20,9 +20,11 @@ int main() {
 #include <gflags/gflags.h>
 #include "rocksdb/comparator.h"
 #include "rocksdb/db.h"
+#include "rocksdb/filter_policy.h"
 #include "rocksdb/perf_context.h"
 #include "rocksdb/slice_transform.h"
 #include "rocksdb/memtablerep.h"
+#include "rocksdb/table.h"
 #include "util/histogram.h"
 #include "util/stop_watch.h"
 #include "util/string_util.h"
@@ -163,6 +165,12 @@ class PrefixTest : public testing::Test {
    options.memtable_prefix_bloom_huge_page_tlb_size =
        FLAGS_memtable_prefix_bloom_huge_page_tlb_size;

+    options.prefix_extractor.reset(NewFixedPrefixTransform(8));
+    BlockBasedTableOptions bbto;
+    bbto.filter_policy.reset(NewBloomFilterPolicy(10, false));
+    bbto.whole_key_filtering = false;
+    options.table_factory.reset(NewBlockBasedTableFactory(bbto));
+
    Status s = DB::Open(options, kDbName,  &db);
    EXPECT_OK(s);
    return std::shared_ptr<DB>(db);
@@ -393,6 +401,55 @@ TEST_F(PrefixTest, TestResult) {
  }
 }

+// Show results in prefix
+TEST_F(PrefixTest, PrefixValid) {
+  for (int num_buckets = 1; num_buckets <= 2; num_buckets++) {
+    FirstOption();
+    while (NextOptions(num_buckets)) {
+      std::cout << "*** Mem table: " << options.memtable_factory->Name()
+                << " number of buckets: " << num_buckets << std::endl;
+      DestroyDB(kDbName, Options());
+      auto db = OpenDb();
+      WriteOptions write_options;
+      ReadOptions read_options;
+
+      // Insert keys with common prefix and one key with different
+      Slice v16("v16");
+      Slice v17("v17");
+      Slice v18("v18");
+      Slice v19("v19");
+      PutKey(db.get(), write_options, 12345, 6, v16);
+      PutKey(db.get(), write_options, 12345, 7, v17);
+      PutKey(db.get(), write_options, 12345, 8, v18);
+      PutKey(db.get(), write_options, 12345, 9, v19);
+      PutKey(db.get(), write_options, 12346, 8, v16);
+      db->Flush(FlushOptions());
+      db->Delete(write_options, TestKeyToSlice(TestKey(12346, 8)));
+      db->Flush(FlushOptions());
+      read_options.prefix_same_as_start = true;
+      std::unique_ptr<Iterator> iter(db->NewIterator(read_options));
+      SeekIterator(iter.get(), 12345, 6);
+      ASSERT_TRUE(iter->Valid());
+      ASSERT_TRUE(v16 == iter->value());
+
+      iter->Next();
+      ASSERT_TRUE(iter->Valid());
+      ASSERT_TRUE(v17 == iter->value());
+
+      iter->Next();
+      ASSERT_TRUE(iter->Valid());
+      ASSERT_TRUE(v18 == iter->value());
+
+      iter->Next();
+      ASSERT_TRUE(iter->Valid());
+      ASSERT_TRUE(v19 == iter->value());
+      iter->Next();
+      ASSERT_FALSE(iter->Valid());
+      ASSERT_EQ(kNotFoundResult, Get(db.get(), read_options, 12346, 8));
+    }
+  }
+}
+
 TEST_F(PrefixTest, DynamicPrefixIterator) {
  while (NextOptions(FLAGS_bucket_count)) {
    std::cout << "*** Mem table: " << options.memtable_factory->Name()