Fixup HISTORY.md for e9ba4ba "validate range tombstone covers positive range"

Moved it from the wrong section (6.10) to the right section (Unreleased).
validate range tombstone covers positive range (#6788 )
2026-11-06 11:02:36 -05:00 · 2020-05-07 14:48:30 -07:00 · 2020-05-07 11:55:30 -07:00 · 2020-05-07 09:32:51 -07:00 · 2020-05-06 18:08:09 -07:00 · 2020-05-06 16:42:37 -07:00
297 changed files with 13096 additions and 3693 deletions
@@ -0,0 +1,41 @@
+name: Check buck targets and code format
+on: [push, pull_request]
+jobs:
+  check:
+    name: Check TARGETS file and code format
+    runs-on: ubuntu-latest
+    steps:
+    - name: Checkout feature branch
+      uses: actions/checkout@v2
+      with:
+        fetch-depth: 0
+
+    - name: Fetch from upstream
+      run: |
+        git remote add upstream https://github.com/facebook/rocksdb.git && git fetch upstream
+
+    - name: Where am I
+      run: |
+        echo git status && git status
+        echo "git remote -v" && git remote -v
+        echo git branch && git branch
+
+    - name: Setup Python
+      uses: actions/setup-python@v1
+
+    - name: Install Dependencies
+      run: python -m pip install --upgrade pip
+
+    - name: Install argparse
+      run: pip install argparse
+
+    - name: Download clang-format-diff.py
+      uses: wei/wget@v1
+      with:
+        args: https://raw.githubusercontent.com/llvm-mirror/clang/master/tools/clang-format/clang-format-diff.py
+
+    - name: Check format
+      run: make check-format
+
+    - name: Compare buckify output
+      run: make check-buck-targets
@@ -50,12 +50,18 @@ env:
  - JOB_NAME=examples # 5-7 minutes
  - JOB_NAME=cmake # 3-5 minutes
  - JOB_NAME=cmake-gcc8 # 3-5 minutes
+  - JOB_NAME=cmake-gcc9 # 3-5 minutes
+  - JOB_NAME=cmake-gcc9-c++20 # 3-5 minutes
  - JOB_NAME=cmake-mingw # 3 minutes

 matrix:
  exclude:
  - os: osx
    env: JOB_NAME=cmake-gcc8
+  - os: osx
+    env: JOB_NAME=cmake-gcc9
+  - os: osx
+    env: JOB_NAME=cmake-gcc9-c++20
  - os: osx
    env: JOB_NAME=cmake-mingw
  - os: osx
@@ -70,7 +76,25 @@ matrix:
    env: JOB_NAME=cmake-mingw
  - os: linux
    compiler: clang
+  # Exclude all but most unique cmake variants for pull requests, but build all in branches
+  - if: type = pull_request
+    os : linux
+    arch: amd64
+    env: JOB_NAME=cmake
+  - if: type = pull_request
+    os : linux
+    arch: amd64
+    env: JOB_NAME=cmake-gcc8
+  - if: type = pull_request
+    os : linux
+    arch: amd64
+    env: JOB_NAME=cmake-gcc9
  # Exclude most osx, arm64 and ppc64le tests for pull requests, but build in branches
+  # Temporarily disable ppc64le unit tests in PRs until Travis gets its act together (#6653)
+  - if: type = pull_request
+    os: linux
+    arch: ppc64le
+    env: TEST_GROUP=platform_dependent
  # NB: the cmake build is a partial java test
  - if: type = pull_request
    os: osx
@@ -116,14 +140,14 @@ matrix:
    os: linux
    arch: ppc64le
    env: TEST_GROUP=4
-  - if: type = pull_request
+  - if: type = pull_request AND commit_message !~ /java/
    os : osx
    env: JOB_NAME=java_test
-  - if: type = pull_request
+  - if: type = pull_request AND commit_message !~ /java/
    os : linux
    arch: arm64
    env: JOB_NAME=java_test
-  - if: type = pull_request
+  - if: type = pull_request AND commit_message !~ /java/
    os: linux
    arch: ppc64le
    env: JOB_NAME=java_test
@@ -157,6 +181,22 @@ matrix:
    os: linux
    arch: ppc64le
    env: JOB_NAME=cmake-gcc8
+  - if: type = pull_request
+    os : linux
+    arch: arm64
+    env: JOB_NAME=cmake-gcc9
+  - if: type = pull_request
+    os: linux
+    arch: ppc64le
+    env: JOB_NAME=cmake-gcc9
+  - if: type = pull_request
+    os : linux
+    arch: arm64
+    env: JOB_NAME=cmake-gcc9-c++20
+  - if: type = pull_request
+    os: linux
+    arch: ppc64le
+    env: JOB_NAME=cmake-gcc9-c++20

 install:
  - if [ "${TRAVIS_OS_NAME}" == osx ]; then
@@ -166,6 +206,10 @@ install:
      sudo apt-get install -y g++-8;
      CC=gcc-8 && CXX=g++-8;
    fi
+  - if [ "${JOB_NAME}" == cmake-gcc9 ] || [ "${JOB_NAME}" == cmake-gcc9-c++20 ]; then
+      sudo apt-get install -y g++-9;
+      CC=gcc-9 && CXX=g++-9;
+    fi
  - if [ "${JOB_NAME}" == cmake-mingw ]; then
      sudo apt-get install -y mingw-w64 ;
    fi
@@ -201,7 +245,7 @@ before_script:
  - ulimit -n 8192

 script:
-  - ${CXX} --version
+  - date; ${CXX} --version
  - if [ `command -v ccache` ]; then ccache -C; fi
  - case $TEST_GROUP in
    platform_dependent)
@@ -235,7 +279,13 @@ script:
      mkdir build && cd build && cmake -DJNI=1 -DWITH_GFLAGS=OFF .. -DCMAKE_C_COMPILER=x86_64-w64-mingw32-gcc -DCMAKE_CXX_COMPILER=x86_64-w64-mingw32-g++ -DCMAKE_SYSTEM_NAME=Windows && make -j4 rocksdb rocksdbjni
      ;;
    cmake*)
-      mkdir build && cd build && cmake -DJNI=1 .. -DCMAKE_BUILD_TYPE=Release && make -j4 rocksdb rocksdbjni
+      case $JOB_NAME in
+        *-c++20)
+          OPT=-DCMAKE_CXX_STANDARD=20
+          ;;
+      esac
+
+      mkdir build && cd build && cmake -DJNI=1 .. -DCMAKE_BUILD_TYPE=Release $OPT && make -j4 rocksdb rocksdbjni
      ;;
    esac
 notifications:
@@ -83,6 +83,10 @@ else()
  option(WITH_FOLLY_DISTRIBUTED_MUTEX "build with folly::DistributedMutex" OFF)
 endif()

+if( NOT DEFINED CMAKE_CXX_STANDARD )
+  set(CMAKE_CXX_STANDARD 11)
+endif()
+
 include(CMakeDependentOption)
 CMAKE_DEPENDENT_OPTION(WITH_GFLAGS "build with GFlags" ON
  "NOT MSVC;NOT MINGW" OFF)
@@ -191,7 +195,6 @@ else()
    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-format -fno-asynchronous-unwind-tables")
    add_definitions(-D_POSIX_C_SOURCE=1)
  endif()
-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
  if(NOT CMAKE_BUILD_TYPE STREQUAL "Debug")
    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fno-omit-frame-pointer")
    include(CheckCXXCompilerFlag)
@@ -254,6 +257,7 @@ include(CheckCXXSourceCompiles)
 if(NOT MSVC)
  set(CMAKE_REQUIRED_FLAGS "-msse4.2 -mpclmul")
 endif()
+
 CHECK_CXX_SOURCE_COMPILES("
 #include <cstdint>
 #include <nmmintrin.h>
@@ -386,7 +390,15 @@ if(MSVC)
    message(STATUS "Debug optimization is enabled")
    set(CMAKE_CXX_FLAGS_DEBUG "/Oxt")
  else()
-    set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} /Od /RTC1 /Gm")
+    set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} /Od /RTC1")
+
+    # Minimal Build is deprecated after MSVC 2015
+    if( MSVC_VERSION GREATER 1900 )
+      set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} /Gm-")
+    else()
+      set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} /Gm")
+    endif()
+
  endif()
  if(WITH_RUNTIME_DEBUG)
    set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} /${RUNTIME_LIBRARY}d")
@@ -506,6 +518,7 @@ find_package(Threads REQUIRED)
 # Main library source code

 set(SOURCES
+        cache/cache.cc
        cache/clock_cache.cc
        cache/lru_cache.cc
        cache/sharded_cache.cc
@@ -595,6 +608,7 @@ set(SOURCES
        memory/arena.cc
        memory/concurrent_arena.cc
        memory/jemalloc_nodump_allocator.cc
+        memory/memkind_kmem_allocator.cc
        memtable/alloc_tracker.cc
        memtable/hash_linklist_rep.cc
        memtable/hash_skiplist_rep.cc
@@ -619,7 +633,6 @@ set(SOURCES
        options/options.cc
        options/options_helper.cc
        options/options_parser.cc
-        options/options_sanity_check.cc
        port/stack_trace.cc
        table/adaptive/adaptive_table_factory.cc
        table/block_based/binary_search_index_reader.cc
@@ -848,7 +861,6 @@ if(ROCKSDB_BUILD_SHARED)
                          LINKER_LANGUAGE CXX
                          VERSION ${rocksdb_VERSION}
                          SOVERSION ${rocksdb_VERSION_MAJOR}
-                          CXX_STANDARD 11
                          OUTPUT_NAME "rocksdb")
  endif()
 endif()
@@ -987,6 +999,7 @@ if(WITH_TESTS)
        db/db_logical_block_size_cache_test.cc
        db/db_universal_compaction_test.cc
        db/db_wal_test.cc
+        db/db_with_timestamp_compaction_test.cc
        db/db_write_test.cc
        db/dbformat_test.cc
        db/deletefile_test.cc
@@ -1029,6 +1042,7 @@ if(WITH_TESTS)
        logging/env_logger_test.cc
        logging/event_logger_test.cc
        memory/arena_test.cc
+        memory/memkind_kmem_allocator_test.cc
        memtable/inlineskiplist_test.cc
        memtable/skiplist_test.cc
        memtable/write_buffer_manager_test.cc
@@ -1049,6 +1063,7 @@ if(WITH_TESTS)
        table/merger_test.cc
        table/sst_file_reader_test.cc
        table/table_test.cc
+        table/block_fetcher_test.cc
        tools/block_cache_analyzer/block_cache_trace_analyzer_test.cc
        tools/ldb_cmd_test.cc
        tools/reduce_levels_test.cc
@@ -1070,8 +1085,10 @@ if(WITH_TESTS)
        util/slice_test.cc
        util/slice_transform_test.cc
        util/timer_queue_test.cc
+        util/timer_test.cc
        util/thread_list_test.cc
        util/thread_local_test.cc
+        util/work_queue_test.cc
        utilities/backupable/backupable_db_test.cc
        utilities/blob_db/blob_db_test.cc
        utilities/cassandra/cassandra_functional_test.cc
@@ -1091,6 +1108,7 @@ if(WITH_TESTS)
        utilities/table_properties_collectors/compact_on_deletion_collector_test.cc
        utilities/transactions/optimistic_transaction_test.cc
        utilities/transactions/transaction_test.cc
+        utilities/transactions/transaction_lock_mgr_test.cc
        utilities/transactions/write_prepared_transaction_test.cc
        utilities/transactions/write_unprepared_transaction_test.cc
        utilities/ttl/ttl_test.cc
@@ -1124,7 +1142,7 @@ if(WITH_TESTS)
        PROPERTIES EXCLUDE_FROM_DEFAULT_BUILD_RELEASE 1
        EXCLUDE_FROM_DEFAULT_BUILD_MINRELEASE 1
        EXCLUDE_FROM_DEFAULT_BUILD_RELWITHDEBINFO 1
-        )
+  )

  foreach(sourcefile ${TESTS})
      get_filename_component(exename ${sourcefile} NAME_WE)
@@ -1134,7 +1152,7 @@ if(WITH_TESTS)
        EXCLUDE_FROM_DEFAULT_BUILD_MINRELEASE 1
        EXCLUDE_FROM_DEFAULT_BUILD_RELWITHDEBINFO 1
        OUTPUT_NAME ${exename}${ARTIFACT_SUFFIX}
-        )
+      )
      target_link_libraries(${CMAKE_PROJECT_NAME}_${exename}${ARTIFACT_SUFFIX} testutillib${ARTIFACT_SUFFIX} testharness gtest ${ROCKSDB_LIB})
      if(NOT "${exename}" MATCHES "db_sanity_test")
        add_test(NAME ${exename} COMMAND ${exename}${ARTIFACT_SUFFIX})
@@ -1,17 +1,44 @@
 # Rocksdb Change Log
 ## Unreleased
+### Bug Fixes
+* Fix consistency checking error swallowing in some cases when options.force_consistency_checks = true.

 ### Public API Change
-* Add NewFileChecksumGenCrc32cFactory to the file checksum public API, such that the builtin Crc32c based file checksum generator factory can be used by applications.
+* Flush(..., column_family) may return Status::ColumnFamilyDropped() instead of Status::InvalidArgument() if column_family is dropped while processing the flush request.
+* BlobDB now explicitly disallows using the default column family's storage directories as blob directory.
+* DeleteRange now returns `Status::InvalidArgument` if the range's end key comes before its start key according to the user comparator. Previously the behavior was undefined.

-### New Features
-* Log CompactOnDeletionCollectorFactory window_size and deletion_trigger parameters in the info log file for troubleshooting purposes.
-* Report kFilesMarkedForCompaction for delete triggered compactions in case of Universal and Levelled Compactions.
-
-## 6.9.1 (04/09/2020)
+## 6.10 (5/2/2020)
 ### Bug Fixes
 * Fix wrong result being read from ingested file. May happen when a key in the file happen to be prefix of another key also in the file. The issue can further cause more data corruption. The issue exists with rocksdb >= 5.0.0 since DB::IngestExternalFile() was introduced.
+* Finish implementation of BlockBasedTableOptions::IndexType::kBinarySearchWithFirstKey. It's now ready for use. Significantly reduces read amplification in some setups, especially for iterator seeks.
+* Fix a bug by updating CURRENT file so that it points to the correct MANIFEST file after best-efforts recovery.
+* Fixed a bug where ColumnFamilyHandle objects were not cleaned up in case an error happened during BlobDB's open after the base DB had been opened.
+* Fix a potential undefined behavior caused by trying to dereference nullable pointer (timestamp argument) in DB::MultiGet.
+* Fix a bug caused by not including user timestamp in MultiGet LookupKey construction. This can lead to wrong query result since the trailing bytes of a user key, if not shorter than timestamp, will be mistaken for user timestamp.
+* Fix a bug caused by using wrong compare function when sorting the input keys of MultiGet with timestamps.
+* Upgraded version of bzip library (1.0.6 -> 1.0.8) used with RocksJava to address potential vulnerabilities if an attacker can manipulate compressed data saved and loaded by RocksDB (not normal). See issue #6703.
+
+### Public API Change
+* Add a ConfigOptions argument to the APIs dealing with converting options to and from strings and files.  The ConfigOptions is meant to replace some of the options (such as input_strings_escaped and ignore_unknown_options) and allow for more parameters to be passed in the future without changing the function signature.
+* Add NewFileChecksumGenCrc32cFactory to the file checksum public API, such that the builtin Crc32c based file checksum generator factory can be used by applications.
+* Add IsDirectory to Env and FS to indicate if a path is a directory.
+
+### New Features
+* Added support for pipelined & parallel compression optimization for `BlockBasedTableBuilder`. This optimization makes block building, block compression and block appending a pipeline, and uses multiple threads to accelerate block compression. Users can set `CompressionOptions::parallel_threads` greater than 1 to enable compression parallelism. This feature is experimental for now.
+* Provide an allocator for memkind to be used with block cache. This is to work with memory technologies (Intel DCPMM is one such technology currently available) that require different libraries for allocation and management (such as PMDK and memkind). The high capacities available make it possible to provision large caches (up to several TBs in size) beyond what is achievable with DRAM.
+* Option `max_background_flushes` can be set dynamically using DB::SetDBOptions().
+* Added functionality in sst_dump tool to check the compressed file size for different compression levels and print the time spent on compressing files with each compression type. Added arguments `--compression_level_from` and `--compression_level_to` to report size of all compression levels and one compression_type must be specified with it so that it will report compressed sizes of one compression type with different levels.
+* Added statistics for redundant insertions into block cache: rocksdb.block.cache.*add.redundant. (There is currently no coordination to ensure that only one thread loads a table block when many threads are trying to access that same table block.)
+
+### Bug Fixes
 * Fix a bug when making options.bottommost_compression, options.compression_opts and options.bottommost_compression_opts dynamically changeable: the modified values are not written to option files or returned back to users when being queried.
+* Fix a bug where index key comparisons were unaccounted in `PerfContext::user_key_comparison_count` for lookups in files written with `format_version >= 3`.
+* Fix many bloom.filter statistics not being updated in batch MultiGet.
+
+### Performance Improvements
+* Improve performance of batch MultiGet with partitioned filters, by sharing block cache lookups to applicable filter blocks.
+* Reduced memory copies when fetching and uncompressing compressed blocks from sst files.

 ## 6.9.0 (03/29/2020)
 ### Behavior changes
@@ -204,8 +204,17 @@ LDFLAGS += -lrados
 endif

 AM_LINK = $(AM_V_CCLD)$(CXX) $^ $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)
-# detect what platform we're building on
-dummy := $(shell (export ROCKSDB_ROOT="$(CURDIR)"; export PORTABLE="$(PORTABLE)"; "$(CURDIR)/build_tools/build_detect_platform" "$(CURDIR)/make_config.mk"))
+# Detect what platform we're building on.
+# Export some common variables that might have been passed as Make variables
+# instead of environment variables.
+dummy := $(shell (export ROCKSDB_ROOT="$(CURDIR)"; \
+                  export COMPILE_WITH_ASAN="$(COMPILE_WITH_ASAN)"; \
+                  export COMPILE_WITH_TSAN="$(COMPILE_WITH_TSAN)"; \
+                  export COMPILE_WITH_UBSAN="$(COMPILE_WITH_UBSAN)"; \
+                  export PORTABLE="$(PORTABLE)"; \
+                  export ROCKSDB_NO_FBCODE="$(ROCKSDB_NO_FBCODE)"; \
+                  export USE_CLANG="$(USE_CLANG)"; \
+                  "$(CURDIR)/build_tools/build_detect_platform" "$(CURDIR)/make_config.mk"))
 # this file is generated by the previous line to set build flags and sources
 include make_config.mk
 export JAVAC_ARGS
@@ -441,7 +450,12 @@ BENCHTOOLOBJECTS = $(BENCH_LIB_SOURCES:.cc=.o) $(LIBOBJECTS) $(TESTUTIL)

 ANALYZETOOLOBJECTS = $(ANALYZER_LIB_SOURCES:.cc=.o)

+ifeq ($(DEBUG_LEVEL),0)
 STRESSTOOLOBJECTS = $(STRESS_LIB_SOURCES:.cc=.o) $(LIBOBJECTS) $(TESTUTIL)
+else
+STRESSTOOLOBJECTS = $(STRESS_LIB_SOURCES:.cc=.o) $(LIBOBJECTS) $(TESTUTIL) \
+	$(TESTHARNESS)
+endif

 EXPOBJECTS = $(LIBOBJECTS) $(TESTUTIL)

@@ -466,6 +480,7 @@ TESTS = \
 	hash_test \
 	random_test \
 	thread_local_test \
+	work_queue_test \
 	rate_limiter_test \
 	perf_context_test \
 	iostats_context_test \
@@ -504,6 +519,7 @@ TESTS = \
 	column_family_test \
 	table_properties_collector_test \
 	arena_test \
+	memkind_kmem_allocator_test \
 	block_test \
 	data_block_hash_index_test \
 	cache_test \
@@ -559,6 +575,7 @@ TESTS = \
 	deletefile_test \
 	obsolete_files_test \
 	table_test \
+	block_fetcher_test \
 	delete_scheduler_test \
 	options_test \
 	options_settable_test \
@@ -583,6 +600,7 @@ TESTS = \
 	compaction_job_stats_test \
 	option_change_migration_test \
 	transaction_test \
+	transaction_lock_mgr_test \
 	ldb_cmd_test \
 	persistent_cache_test \
 	statistics_test \
@@ -605,6 +623,8 @@ TESTS = \
 	defer_test \
 	blob_file_addition_test \
 	blob_file_garbage_test \
+	timer_test \
+	db_with_timestamp_compaction_test \

 ifeq ($(USE_FOLLY_DISTRIBUTED_MUTEX),1)
 	TESTS += folly_synchronization_distributed_mutex_test
@@ -629,6 +649,7 @@ PARALLEL_TEST = \
 	persistent_cache_test \
 	table_test \
 	transaction_test \
+	transaction_lock_mgr_test \
 	write_prepared_transaction_test \
 	write_unprepared_transaction_test \

@@ -945,7 +966,7 @@ check: all
 	    $(MAKE) T="$$t" TMPD=$(TMPD) check_0;                       \
 	else                                                            \
 	    for t in $(TESTS); do                                       \
-	      echo "===== Running $$t"; ./$$t || exit 1; done;          \
+	      echo "===== Running $$t (`date`)"; ./$$t || exit 1; done;          \
 	fi
 	rm -rf $(TMPD)
 ifneq ($(PLATFORM), OS_AIX)
@@ -955,10 +976,12 @@ ifeq ($(filter -DROCKSDB_LITE,$(OPT)),)
 	sh tools/rocksdb_dump_test.sh
 endif
 endif
+	$(MAKE) check-format
+	$(MAKE) check-buck-targets

 # TODO add ldb_tests
 check_some: $(SUBSET)
-	for t in $(SUBSET); do echo "===== Running $$t"; ./$$t || exit 1; done
+	for t in $(SUBSET); do echo "===== Running $$t (`date`)"; ./$$t || exit 1; done

 .PHONY: ldb_tests
 ldb_tests: ldb
@@ -1064,7 +1087,7 @@ ifneq ($(PAR_TEST),)
 parloop:
 	ret_bad=0;							\
 	for t in $(PAR_TEST); do		\
-		echo "===== Running $$t in parallel $(NUM_PAR)";\
+		echo "===== Running $$t in parallel $(NUM_PAR) (`date`)";\
 		if [ $(db_test) -eq 1 ]; then \
 			seq $(J) | v="$$t" build_tools/gnu_parallel --gnu --plain 's=$(TMPD)/rdb-{};  export TEST_TMPDIR=$$s;' \
 				'timeout 2m ./db_test --gtest_filter=$$v >> $$s/log-{} 2>1'; \
@@ -1175,6 +1198,12 @@ tags0:
 format:
 	build_tools/format-diff.sh

+check-format:
+	build_tools/format-diff.sh -c
+
+check-buck-targets:
+	buckifier/check_buck_targets.sh
+
 package:
 	bash build_tools/make_package.sh $(SHARED_MAJOR).$(SHARED_MINOR)

@@ -1237,6 +1266,9 @@ db_repl_stress: tools/db_repl_stress.o $(LIBOBJECTS) $(TESTUTIL)

 arena_test: memory/arena_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(AM_LINK)
+	
+memkind_kmem_allocator_test: memory/memkind_kmem_allocator_test.o $(LIBOBJECTS) $(TESTHARNESS)
+	$(AM_LINK)	

 autovector_test: util/autovector_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(AM_LINK)
@@ -1295,6 +1327,9 @@ histogram_test: monitoring/histogram_test.o $(LIBOBJECTS) $(TESTHARNESS)
 thread_local_test: util/thread_local_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(AM_LINK)

+work_queue_test: util/work_queue_test.o $(LIBOBJECTS) $(TESTHARNESS)
+	$(AM_LINK)
+
 corruption_test: db/corruption_test.o db/db_test_util.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(AM_LINK)

@@ -1313,6 +1348,9 @@ db_basic_test: db/db_basic_test.o db/db_test_util.o $(LIBOBJECTS) $(TESTHARNESS)
 db_with_timestamp_basic_test: db/db_with_timestamp_basic_test.o db/db_test_util.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(AM_LINK)

+db_with_timestamp_compaction_test: db/db_with_timestamp_compaction_test.o db/db_test_util.o $(LIBOBJECTS) $(TESTHARNESS)
+	$(AM_LINK)
+
 db_encryption_test: db/db_encryption_test.o db/db_test_util.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(AM_LINK)

@@ -1531,6 +1569,9 @@ cleanable_test: table/cleanable_test.o $(LIBOBJECTS) $(TESTHARNESS)
 table_test: table/table_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(AM_LINK)

+block_fetcher_test: table/block_fetcher_test.o $(LIBOBJECTS) $(TESTHARNESS)
+	$(AM_LINK)
+
 block_test: table/block_based/block_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(AM_LINK)

@@ -1669,6 +1710,9 @@ write_callback_test: db/write_callback_test.o $(LIBOBJECTS) $(TESTHARNESS)
 heap_test: util/heap_test.o $(GTEST)
 	$(AM_LINK)

+transaction_lock_mgr_test: utilities/transactions/transaction_lock_mgr_test.o $(LIBOBJECTS) $(TESTHARNESS)
+	$(AM_LINK)
+
 transaction_test: utilities/transactions/transaction_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(AM_LINK)

@@ -1744,6 +1788,9 @@ blob_file_addition_test: db/blob/blob_file_addition_test.o $(LIBOBJECTS) $(TESTH
 blob_file_garbage_test: db/blob/blob_file_garbage_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(AM_LINK)

+timer_test: util/timer_test.o $(LIBOBJECTS) $(TESTHARNESS)
+	$(AM_LINK)
+
 #-------------------------------------------------
 # make install related stuff
 INSTALL_PATH ?= /usr/local
@@ -1823,9 +1870,9 @@ SHA256_CMD = sha256sum
 ZLIB_VER ?= 1.2.11
 ZLIB_SHA256 ?= c3e5e9fdd5004dcb542feda5ee4f0ff0744628baf8ed2dd5d66f8ca1197cb1a1
 ZLIB_DOWNLOAD_BASE ?= http://zlib.net
-BZIP2_VER ?= 1.0.6
-BZIP2_SHA256 ?= a2848f34fcd5d6cf47def00461fcb528a0484d8edef8208d6d2e2909dc61d9cd
-BZIP2_DOWNLOAD_BASE ?= https://downloads.sourceforge.net/project/bzip2
+BZIP2_VER ?= 1.0.8
+BZIP2_SHA256 ?= ab5a03176ee106d3f0fa90e381da478ddae405918153cca248e682cd0c4a2269
+BZIP2_DOWNLOAD_BASE ?= https://sourceware.org/pub/bzip2
 SNAPPY_VER ?= 1.1.8
 SNAPPY_SHA256 ?= 16b677f07832a612b0836178db7f374e414f94657c138e6993cbfc5dcc58651f
 SNAPPY_DOWNLOAD_BASE ?= https://github.com/google/snappy/archive
@@ -24,7 +24,7 @@ The public interface is in `include/`.  Callers should not include or
 rely on the details of any other header files in this package.  Those
 internal APIs may be changed without warning.

-Design discussions are conducted in https://www.facebook.com/groups/rocksdb.dev/
+Design discussions are conducted in https://www.facebook.com/groups/rocksdb.dev/ and https://rocksdb.slack.com/

 ## License

@@ -112,6 +112,7 @@ ROCKSDB_OS_DEPS += ([(
 cpp_library(
    name = "rocksdb_lib",
    srcs = [
+        "cache/cache.cc",
        "cache/clock_cache.cc",
        "cache/lru_cache.cc",
        "cache/sharded_cache.cc",
@@ -204,6 +205,7 @@ cpp_library(
        "memory/arena.cc",
        "memory/concurrent_arena.cc",
        "memory/jemalloc_nodump_allocator.cc",
+        "memory/memkind_kmem_allocator.cc",
        "memtable/alloc_tracker.cc",
        "memtable/hash_linklist_rep.cc",
        "memtable/hash_skiplist_rep.cc",
@@ -229,7 +231,6 @@ cpp_library(
        "options/options.cc",
        "options/options_helper.cc",
        "options/options_parser.cc",
-        "options/options_sanity_check.cc",
        "port/port_posix.cc",
        "port/stack_trace.cc",
        "table/adaptive/adaptive_table_factory.cc",
@@ -436,7 +437,10 @@ cpp_library(
    os_deps = ROCKSDB_OS_DEPS,
    os_preprocessor_flags = ROCKSDB_OS_PREPROCESSOR_FLAGS,
    preprocessor_flags = ROCKSDB_PREPROCESSOR_FLAGS,
-    deps = [":rocksdb_lib"],
+    deps = [
+        ":rocksdb_lib",
+        ":rocksdb_test_lib",
+    ],
    external_deps = ROCKSDB_EXTERNAL_DEPS,
 )

@@ -525,6 +529,13 @@ ROCKS_TESTS = [
        [],
        [],
    ],
+    [
+        "block_fetcher_test",
+        "table/block_fetcher_test.cc",
+        "serial",
+        [],
+        [],
+    ],
    [
        "block_test",
        "table/block_based/block_test.cc",
@@ -931,6 +942,13 @@ ROCKS_TESTS = [
        [],
        [],
    ],
+    [
+        "db_with_timestamp_compaction_test",
+        "db/db_with_timestamp_compaction_test.cc",
+        "serial",
+        [],
+        [],
+    ],
    [
        "db_write_test",
        "db/db_write_test.cc",
@@ -1169,6 +1187,13 @@ ROCKS_TESTS = [
        [],
        [],
    ],
+    [
+        "memkind_kmem_allocator_test",
+        "memory/memkind_kmem_allocator_test.cc",
+        "serial",
+        [],
+        [],
+    ],
    [
        "memory_test",
        "utilities/memory/memory_test.cc",
@@ -1456,6 +1481,13 @@ ROCKS_TESTS = [
        [],
        [],
    ],
+    [
+        "timer_test",
+        "util/timer_test.cc",
+        "serial",
+        [],
+        [],
+    ],
    [
        "trace_analyzer_test",
        "tools/trace_analyzer_test.cc",
@@ -1463,6 +1495,13 @@ ROCKS_TESTS = [
        [],
        [],
    ],
+    [
+        "transaction_lock_mgr_test",
+        "utilities/transactions/transaction_lock_mgr_test.cc",
+        "parallel",
+        [],
+        [],
+    ],
    [
        "transaction_test",
        "utilities/transactions/transaction_test.cc",
@@ -1512,6 +1551,13 @@ ROCKS_TESTS = [
        [],
        [],
    ],
+    [
+        "work_queue_test",
+        "util/work_queue_test.cc",
+        "serial",
+        [],
+        [],
+    ],
    [
        "write_batch_test",
        "db/write_batch_test.cc",
@@ -106,3 +106,6 @@ LzLabs is using RocksDB as a storage engine in their multi-database distributed
 ## Nebula Graph

 [Nebula Graph](https://github.com/vesoft-inc/nebula) is a distributed, scalable, lightning-fast, open source graph database capable of hosting super large scale graphs with dozens of billions of vertices (nodes) and trillions of edges, with milliseconds of latency.
+
+## YugabyteDB
+[YugabyteDB](https://www.yugabyte.com/) is an open source, high performance, distributed SQL database that uses RocksDB as its storage layer. For more information, please see https://github.com/yugabyte/yugabyte-db/.
@@ -1,6 +1,6 @@
 version: 1.0.{build}

-image: Visual Studio 2017
+image: Visual Studio 2019

 environment:
  JAVA_HOME: C:\Program Files\Java\jdk1.8.0
@@ -24,6 +24,15 @@ environment:
    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
      CMAKE_GENERATOR: Visual Studio 15 Win64
      DEV_ENV: C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\Common7\IDE\devenv.com
+    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
+      CMAKE_GENERATOR: Visual Studio 16
+      CMAKE_PLATEFORM_NAME: x64
+      DEV_ENV: C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\Common7\IDE\devenv.com
+    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
+      CMAKE_GENERATOR: Visual Studio 16
+      CMAKE_PLATEFORM_NAME: x64
+      CMAKE_OPT: -DCMAKE_CXX_STANDARD=20
+      DEV_ENV: C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\Common7\IDE\devenv.com

 install:
  - md %THIRDPARTY_HOME%
@@ -34,7 +43,8 @@ install:
  - cd snappy-1.1.7
  - mkdir build
  - cd build
-  - cmake -G "%CMAKE_GENERATOR%" ..
+  - if DEFINED CMAKE_PLATEFORM_NAME (set "PLATEFORM_OPT=-A %CMAKE_PLATEFORM_NAME%")
+  - cmake .. -G "%CMAKE_GENERATOR%" %PLATEFORM_OPT%
  - msbuild Snappy.sln /p:Configuration=Debug /p:Platform=x64
  - msbuild Snappy.sln /p:Configuration=Release /p:Platform=x64
  - echo "Building LZ4 dependency..."
@@ -57,7 +67,8 @@ install:
 before_build:
  - md %APPVEYOR_BUILD_FOLDER%\build
  - cd %APPVEYOR_BUILD_FOLDER%\build
-  - cmake -G "%CMAKE_GENERATOR%" -DCMAKE_BUILD_TYPE=Debug -DOPTDBG=1 -DPORTABLE=1 -DSNAPPY=1 -DLZ4=1 -DZSTD=1 -DXPRESS=1 -DJNI=1 ..
+  - if DEFINED CMAKE_PLATEFORM_NAME (set "PLATEFORM_OPT=-A %CMAKE_PLATEFORM_NAME%")
+  - cmake .. -G "%CMAKE_GENERATOR%" %PLATEFORM_OPT% %CMAKE_OPT% -DCMAKE_BUILD_TYPE=Debug -DOPTDBG=1 -DPORTABLE=1 -DSNAPPY=1 -DLZ4=1 -DZSTD=1 -DXPRESS=1 -DJNI=1
  - cd ..

 build:
@@ -173,7 +173,7 @@ def generate_targets(repo_path, deps_map):
        src_mk.get("ANALYZER_LIB_SOURCES", [])
        + src_mk.get('STRESS_LIB_SOURCES', [])
        + ["test_util/testutil.cc"],
-        [":rocksdb_lib"])
+        [":rocksdb_lib", ":rocksdb_test_lib"])

    print("Extra dependencies:\n{0}".format(str(deps_map)))
    # test for every test we found in the Makefile
@@ -0,0 +1,31 @@
+#!/usr/bin/env bash
+# Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+# If clang_format_diff.py command is not specfied, we assume we are able to
+# access directly without any path.
+
+TGT_DIFF=`git diff TARGETS | head -n 1`
+
+if [ ! -z "$TGT_DIFF" ]
+then
+  echo "TARGETS file has uncommitted changes. Skip this check."
+  exit 0
+fi
+
+echo Backup original TARGETS file.
+
+cp TARGETS TARGETS.bkp
+
+python buckifier/buckify_rocksdb.py
+
+TGT_DIFF=`git diff TARGETS | head -n 1`
+
+if [ -z "$TGT_DIFF" ]
+then
+  mv TARGETS.bkp TARGETS
+  exit 0
+else
+  echo "Please run 'python buckifier/buckify_rocksdb.py' to update TARGETS file."
+  echo "Do not manually update TARGETS file."
+  mv TARGETS.bkp TARGETS
+  exit 1
+fi
@@ -28,6 +28,7 @@
 #       -DZSTD                      if the ZSTD library is present
 #       -DNUMA                      if the NUMA library is present
 #       -DTBB                       if the TBB library is present
+#       -DMEMKIND                   if the memkind library is present
 #
 # Using gflags in rocksdb:
 # Our project depends on gflags, which requires users to take some extra steps
@@ -245,6 +246,10 @@ JAVAC_ARGS="-source 7"
 if [ "$CROSS_COMPILE" = "true" -o "$FBCODE_BUILD" = "true" ]; then
    # Cross-compiling; do not try any compilation tests.
    # Also don't need any compilation tests if compiling on fbcode
+    if [ "$FBCODE_BUILD" = "true" ]; then
+      # Enable backtrace on fbcode since the necessary libraries are present
+      COMMON_FLAGS="$COMMON_FLAGS -DROCKSDB_BACKTRACE"
+    fi
    true
 else
    if ! test $ROCKSDB_DISABLE_FALLOCATE; then
@@ -425,7 +430,23 @@ EOF
            COMMON_FLAGS="$COMMON_FLAGS -DROCKSDB_MALLOC_USABLE_SIZE"
        fi
    fi
-
+    
+    if ! test $ROCKSDB_DISABLE_MEMKIND; then
+        # Test whether memkind library is installed
+        $CXX $CFLAGS $COMMON_FLAGS -lmemkind -x c++ - -o /dev/null 2>/dev/null  <<EOF
+          #include <memkind.h>
+          int main() {
+            memkind_malloc(MEMKIND_DAX_KMEM, 1024);
+            return 0;
+          }
+EOF
+        if [ "$?" = 0 ]; then
+            COMMON_FLAGS="$COMMON_FLAGS -DMEMKIND"
+            PLATFORM_LDFLAGS="$PLATFORM_LDFLAGS -lmemkind"
+            JAVA_LDFLAGS="$JAVA_LDFLAGS -lmemkind"
+        fi
+    fi
+    
    if ! test $ROCKSDB_DISABLE_PTHREAD_MUTEX_ADAPTIVE_NP; then
        # Test whether PTHREAD_MUTEX_ADAPTIVE_NP mutex type is available
        $CXX $CFLAGS -x c++ - -o /dev/null 2>/dev/null  <<EOF
@@ -684,6 +705,7 @@ EOF
  fi
 fi

+
 if [ "$FBCODE_BUILD" != "true" -a "$PLATFORM" = OS_LINUX ]; then
  $CXX $COMMON_FLAGS $PLATFORM_SHARED_CFLAGS -x c++ -c - -o test_dl.o 2>/dev/null <<EOF
  void dummy_func() {}
@@ -2,6 +2,30 @@
 # Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
 # If clang_format_diff.py command is not specfied, we assume we are able to
 # access directly without any path.
+
+print_usage () {
+  echo "Usage:"
+  echo "format-diff.sh [OPTIONS]"
+  echo "-c: check only."
+  echo "-h: print this message."
+}
+
+while getopts ':ch' OPTION; do
+  case "$OPTION" in
+    c)
+      CHECK_ONLY=1
+      ;;
+    h)
+      print_usage
+      exit 1
+      ;;
+    ?)
+      print_usage
+      exit 1
+      ;;
+  esac
+done
+
 if [ -z $CLANG_FORMAT_DIFF ]
 then
 CLANG_FORMAT_DIFF="clang-format-diff.py"
@@ -10,18 +34,28 @@ fi
 # Check clang-format-diff.py
 if ! which $CLANG_FORMAT_DIFF &> /dev/null
 then
-  echo "You didn't have clang-format-diff.py and/or clang-format available in your computer!"
-  echo "You can download clang-format-diff.py by running: "
-  echo "    curl --location http://goo.gl/iUW1u2 -o ${CLANG_FORMAT_DIFF}"
-  echo "You can download clang-format by running:"
-  echo "    brew install clang-format"
-  echo "  Or"
-  echo "    apt install clang-format"
-  echo "  This might work too:"
-  echo "    yum install git-clang-format"
-  echo "Then, move both files (i.e. ${CLANG_FORMAT_DIFF} and clang-format) to some directory within PATH=${PATH}"
-  echo "and make sure ${CLANG_FORMAT_DIFF} is executable."
-  exit 128
+  if [ ! -f ./clang-format-diff.py ]
+  then
+    echo "You didn't have clang-format-diff.py and/or clang-format available in your computer!"
+    echo "You can download clang-format-diff.py by running: "
+    echo "    curl --location http://goo.gl/iUW1u2 -o ${CLANG_FORMAT_DIFF}"
+    echo "You can download clang-format by running:"
+    echo "    brew install clang-format"
+    echo "  Or"
+    echo "    apt install clang-format"
+    echo "  This might work too:"
+    echo "    yum install git-clang-format"
+    echo "Then, move both files (i.e. ${CLANG_FORMAT_DIFF} and clang-format) to some directory within PATH=${PATH}"
+    echo "and make sure ${CLANG_FORMAT_DIFF} is executable."
+    exit 128
+  else
+    if [ -x ./clang-format-diff.py ]
+    then
+      PATH=$PATH:.
+    else
+      CLANG_FORMAT_DIFF="python ./clang-format-diff.py"
+    fi
+  fi
 fi

 # Check argparse, a library that clang-format-diff.py requires.
@@ -87,6 +121,10 @@ if [ -z "$diffs" ]
 then
  echo "Nothing needs to be reformatted!"
  exit 0
+elif [ $CHECK_ONLY ]
+then
+  echo "Your change has unformatted code. Please run make format!"
+  exit 1
 fi

 # Highlight the insertion/deletion from the clang-format-diff.py's output
@@ -121,7 +159,7 @@ if [ -z "$uncommitted_code" ]
 then
  git diff -U0 "$FORMAT_UPSTREAM_MERGE_BASE" | $CLANG_FORMAT_DIFF -i -p 1
 else
-  git diff -U0 HEAD^ | $CLANG_FORMAT_DIFF -i -p 1
+  git diff -U0 HEAD | $CLANG_FORMAT_DIFF -i -p 1
 fi
 echo "Files reformatted!"

@@ -818,6 +818,8 @@ run_format_compatible()
  rm -rf /dev/shm/rocksdb
  mkdir /dev/shm/rocksdb

+  export https_proxy="fwdproxy:8080"
+  
  tools/check_format_compatible.sh
 }

@@ -1,9 +1,9 @@
 #!/bin/bash
 # Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
-set -e
+set -ex

-ROCKSDB_VERSION="5.10.3"
-ZSTD_VERSION="1.1.3"
+ROCKSDB_VERSION="6.7.3"
+ZSTD_VERSION="1.4.4"

 echo "This script configures CentOS with everything needed to build and run RocksDB"

@@ -40,5 +40,6 @@ cd /usr/local/rocksdb
 chown -R vagrant:vagrant /usr/local/rocksdb/
 sudo -u vagrant make static_lib
 cd examples/
-sudo -u vagrant make all
-sudo -u vagrant ./c_simple_example
+sudo -u vagrant LD_LIBRARY_PATH=/usr/local/lib/ make all
+sudo -u vagrant LD_LIBRARY_PATH=/usr/local/lib/ ./c_simple_example
+
@@ -0,0 +1,41 @@
+//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root 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 "rocksdb/cache.h"
+
+#include "cache/lru_cache.h"
+#include "options/options_helper.h"
+#include "util/string_util.h"
+
+namespace ROCKSDB_NAMESPACE {
+Status Cache::CreateFromString(const ConfigOptions& /*opts*/,
+                               const std::string& value,
+                               std::shared_ptr<Cache>* result) {
+  Status status;
+  std::shared_ptr<Cache> cache;
+  if (value.find('=') == std::string::npos) {
+    cache = NewLRUCache(ParseSizeT(value));
+  } else {
+#ifndef ROCKSDB_LITE
+    LRUCacheOptions cache_opts;
+    if (!ParseOptionHelper(reinterpret_cast<char*>(&cache_opts),
+                           OptionType::kLRUCacheOptions, value)) {
+      status = Status::InvalidArgument("Invalid cache options");
+    }
+    cache = NewLRUCache(cache_opts);
+#else
+    status = Status::NotSupported("Cannot load cache in LITE mode ", value);
+#endif  //! ROCKSDB_LITE
+  }
+  if (status.ok()) {
+    result->swap(cache);
+  }
+  return status;
+}
+}  // namespace ROCKSDB_NAMESPACE
@@ -14,34 +14,47 @@ int main() {
 #include <stdio.h>
 #include <sys/types.h>
 #include <cinttypes>
+#include <limits>

 #include "port/port.h"
 #include "rocksdb/cache.h"
 #include "rocksdb/db.h"
 #include "rocksdb/env.h"
+#include "util/coding.h"
 #include "util/gflags_compat.h"
+#include "util/hash.h"
 #include "util/mutexlock.h"
 #include "util/random.h"

 using GFLAGS_NAMESPACE::ParseCommandLineFlags;

-static const uint32_t KB = 1024;
+static constexpr uint32_t KiB = uint32_t{1} << 10;
+static constexpr uint32_t MiB = KiB << 10;
+static constexpr uint64_t GiB = MiB << 10;

-DEFINE_int32(threads, 16, "Number of concurrent threads to run.");
-DEFINE_int64(cache_size, 8 * KB * KB,
-             "Number of bytes to use as a cache of uncompressed data.");
-DEFINE_int32(num_shard_bits, 4, "shard_bits.");
+DEFINE_uint32(threads, 16, "Number of concurrent threads to run.");
+DEFINE_uint64(cache_size, 1 * GiB,
+              "Number of bytes to use as a cache of uncompressed data.");
+DEFINE_uint32(num_shard_bits, 6, "shard_bits.");

-DEFINE_int64(max_key, 1 * KB * KB * KB, "Max number of key to place in cache");
-DEFINE_uint64(ops_per_thread, 1200000, "Number of operations per thread.");
+DEFINE_double(resident_ratio, 0.25,
+              "Ratio of keys fitting in cache to keyspace.");
+DEFINE_uint64(ops_per_thread, 0,
+              "Number of operations per thread. (Default: 5 * keyspace size)");
+DEFINE_uint32(value_bytes, 8 * KiB, "Size of each value added.");

-DEFINE_bool(populate_cache, false, "Populate cache before operations");
-DEFINE_int32(insert_percent, 40,
-             "Ratio of insert to total workload (expressed as a percentage)");
-DEFINE_int32(lookup_percent, 50,
-             "Ratio of lookup to total workload (expressed as a percentage)");
-DEFINE_int32(erase_percent, 10,
-             "Ratio of erase to total workload (expressed as a percentage)");
+DEFINE_uint32(skew, 5, "Degree of skew in key selection");
+DEFINE_bool(populate_cache, true, "Populate cache before operations");
+
+DEFINE_uint32(lookup_insert_percent, 87,
+              "Ratio of lookup (+ insert on not found) to total workload "
+              "(expressed as a percentage)");
+DEFINE_uint32(insert_percent, 2,
+              "Ratio of insert to total workload (expressed as a percentage)");
+DEFINE_uint32(lookup_percent, 10,
+              "Ratio of lookup to total workload (expressed as a percentage)");
+DEFINE_uint32(erase_percent, 1,
+              "Ratio of erase to total workload (expressed as a percentage)");

 DEFINE_bool(use_clock_cache, false, "");

@@ -49,21 +62,15 @@ namespace ROCKSDB_NAMESPACE {

 class CacheBench;
 namespace {
-void deleter(const Slice& /*key*/, void* value) {
-    delete reinterpret_cast<char *>(value);
-}
-
 // State shared by all concurrent executions of the same benchmark.
 class SharedState {
 public:
  explicit SharedState(CacheBench* cache_bench)
      : cv_(&mu_),
-        num_threads_(FLAGS_threads),
        num_initialized_(0),
        start_(false),
        num_done_(0),
-        cache_bench_(cache_bench) {
-  }
+        cache_bench_(cache_bench) {}

  ~SharedState() {}

@@ -87,13 +94,9 @@ class SharedState {
    num_done_++;
  }

-  bool AllInitialized() const {
-    return num_initialized_ >= num_threads_;
-  }
+  bool AllInitialized() const { return num_initialized_ >= FLAGS_threads; }

-  bool AllDone() const {
-    return num_done_ >= num_threads_;
-  }
+  bool AllDone() const { return num_done_ >= FLAGS_threads; }

  void SetStart() {
    start_ = true;
@@ -107,7 +110,6 @@ class SharedState {
  port::Mutex mu_;
  port::CondVar cv_;

-  const uint64_t num_threads_;
  uint64_t num_initialized_;
  bool start_;
  uint64_t num_done_;
@@ -118,17 +120,69 @@ class SharedState {
 // Per-thread state for concurrent executions of the same benchmark.
 struct ThreadState {
  uint32_t tid;
-  Random rnd;
+  Random64 rnd;
  SharedState* shared;

  ThreadState(uint32_t index, SharedState* _shared)
      : tid(index), rnd(1000 + index), shared(_shared) {}
 };
+
+struct KeyGen {
+  char key_data[27];
+
+  Slice GetRand(Random64& rnd, uint64_t max_key) {
+    uint64_t raw = rnd.Next();
+    // Skew according to setting
+    for (uint32_t i = 0; i < FLAGS_skew; ++i) {
+      raw = std::min(raw, rnd.Next());
+    }
+    uint64_t key = fastrange64(raw, max_key);
+    // Variable size and alignment
+    size_t off = key % 8;
+    key_data[0] = char{42};
+    EncodeFixed64(key_data + 1, key);
+    key_data[9] = char{11};
+    EncodeFixed64(key_data + 10, key);
+    key_data[18] = char{4};
+    EncodeFixed64(key_data + 19, key);
+    return Slice(&key_data[off], sizeof(key_data) - off);
+  }
+};
+
+char* createValue(Random64& rnd) {
+  char* rv = new char[FLAGS_value_bytes];
+  // Fill with some filler data, and take some CPU time
+  for (uint32_t i = 0; i < FLAGS_value_bytes; i += 8) {
+    EncodeFixed64(rv + i, rnd.Next());
+  }
+  return rv;
+}
+
+void deleter(const Slice& /*key*/, void* value) {
+  delete[] static_cast<char*>(value);
+}
 }  // namespace

 class CacheBench {
+  static constexpr uint64_t kHundredthUint64 =
+      std::numeric_limits<uint64_t>::max() / 100U;
+
 public:
-  CacheBench() : num_threads_(FLAGS_threads) {
+  CacheBench()
+      : max_key_(static_cast<uint64_t>(FLAGS_cache_size / FLAGS_resident_ratio /
+                                       FLAGS_value_bytes)),
+        lookup_insert_threshold_(kHundredthUint64 *
+                                 FLAGS_lookup_insert_percent),
+        insert_threshold_(lookup_insert_threshold_ +
+                          kHundredthUint64 * FLAGS_insert_percent),
+        lookup_threshold_(insert_threshold_ +
+                          kHundredthUint64 * FLAGS_lookup_percent),
+        erase_threshold_(lookup_threshold_ +
+                         kHundredthUint64 * FLAGS_erase_percent) {
+    if (erase_threshold_ != 100U * kHundredthUint64) {
+      fprintf(stderr, "Percentages must add to 100.\n");
+      exit(1);
+    }
    if (FLAGS_use_clock_cache) {
      cache_ = NewClockCache(FLAGS_cache_size, FLAGS_num_shard_bits);
      if (!cache_) {
@@ -138,18 +192,19 @@ class CacheBench {
    } else {
      cache_ = NewLRUCache(FLAGS_cache_size, FLAGS_num_shard_bits);
    }
+    if (FLAGS_ops_per_thread == 0) {
+      FLAGS_ops_per_thread = 5 * max_key_;
+    }
  }

  ~CacheBench() {}

  void PopulateCache() {
-    Random rnd(1);
-    for (int64_t i = 0; i < FLAGS_cache_size; i++) {
-      uint64_t rand_key = rnd.Next() % FLAGS_max_key;
-      // Cast uint64* to be char*, data would be copied to cache
-      Slice key(reinterpret_cast<char*>(&rand_key), 8);
-      // do insert
-      cache_->Insert(key, new char[10], 1, &deleter);
+    Random64 rnd(1);
+    KeyGen keygen;
+    for (uint64_t i = 0; i < 2 * FLAGS_cache_size; i += FLAGS_value_bytes) {
+      cache_->Insert(keygen.GetRand(rnd, max_key_), createValue(rnd),
+                     FLAGS_value_bytes, &deleter);
    }
  }

@@ -158,10 +213,10 @@ class CacheBench {

    PrintEnv();
    SharedState shared(this);
-    std::vector<ThreadState*> threads(num_threads_);
-    for (uint32_t i = 0; i < num_threads_; i++) {
-      threads[i] = new ThreadState(i, &shared);
-      env->StartThread(ThreadBody, threads[i]);
+    std::vector<std::unique_ptr<ThreadState> > threads(FLAGS_threads);
+    for (uint32_t i = 0; i < FLAGS_threads; i++) {
+      threads[i].reset(new ThreadState(i, &shared));
+      env->StartThread(ThreadBody, threads[i].get());
    }
    {
      MutexLock l(shared.GetMutex());
@@ -192,10 +247,15 @@ class CacheBench {

 private:
  std::shared_ptr<Cache> cache_;
-  uint32_t num_threads_;
+  const uint64_t max_key_;
+  // Cumulative thresholds in the space of a random uint64_t
+  const uint64_t lookup_insert_threshold_;
+  const uint64_t insert_threshold_;
+  const uint64_t lookup_threshold_;
+  const uint64_t erase_threshold_;

  static void ThreadBody(void* v) {
-    ThreadState* thread = reinterpret_cast<ThreadState*>(v);
+    ThreadState* thread = static_cast<ThreadState*>(v);
    SharedState* shared = thread->shared;

    {
@@ -220,40 +280,78 @@ class CacheBench {
  }

  void OperateCache(ThreadState* thread) {
+    // To use looked-up values
+    uint64_t result = 0;
+    // To hold handles for a non-trivial amount of time
+    Cache::Handle* handle = nullptr;
+    KeyGen gen;
    for (uint64_t i = 0; i < FLAGS_ops_per_thread; i++) {
-      uint64_t rand_key = thread->rnd.Next() % FLAGS_max_key;
-      // Cast uint64* to be char*, data would be copied to cache
-      Slice key(reinterpret_cast<char*>(&rand_key), 8);
-      int32_t prob_op = thread->rnd.Uniform(100);
-      if (prob_op >= 0 && prob_op < FLAGS_insert_percent) {
-        // do insert
-        cache_->Insert(key, new char[10], 1, &deleter);
-      } else if (prob_op -= FLAGS_insert_percent &&
-                 prob_op < FLAGS_lookup_percent) {
-        // do lookup
-        auto handle = cache_->Lookup(key);
+      Slice key = gen.GetRand(thread->rnd, max_key_);
+      uint64_t random_op = thread->rnd.Next();
+      if (random_op < lookup_insert_threshold_) {
        if (handle) {
          cache_->Release(handle);
+          handle = nullptr;
        }
-      } else if (prob_op -= FLAGS_lookup_percent &&
-                 prob_op < FLAGS_erase_percent) {
+        // do lookup
+        handle = cache_->Lookup(key);
+        if (handle) {
+          // do something with the data
+          result += NPHash64(static_cast<char*>(cache_->Value(handle)),
+                             FLAGS_value_bytes);
+        } else {
+          // do insert
+          cache_->Insert(key, createValue(thread->rnd), FLAGS_value_bytes,
+                         &deleter, &handle);
+        }
+      } else if (random_op < insert_threshold_) {
+        if (handle) {
+          cache_->Release(handle);
+          handle = nullptr;
+        }
+        // do insert
+        cache_->Insert(key, createValue(thread->rnd), FLAGS_value_bytes,
+                       &deleter, &handle);
+      } else if (random_op < lookup_threshold_) {
+        if (handle) {
+          cache_->Release(handle);
+          handle = nullptr;
+        }
+        // do lookup
+        handle = cache_->Lookup(key);
+        if (handle) {
+          // do something with the data
+          result += NPHash64(static_cast<char*>(cache_->Value(handle)),
+                             FLAGS_value_bytes);
+        }
+      } else if (random_op < erase_threshold_) {
        // do erase
        cache_->Erase(key);
+      } else {
+        // Should be extremely unlikely (noop)
+        assert(random_op >= kHundredthUint64 * 100U);
      }
    }
+    if (handle) {
+      cache_->Release(handle);
+      handle = nullptr;
+    }
  }

  void PrintEnv() const {
    printf("RocksDB version     : %d.%d\n", kMajorVersion, kMinorVersion);
-    printf("Number of threads   : %d\n", FLAGS_threads);
+    printf("Number of threads   : %u\n", FLAGS_threads);
    printf("Ops per thread      : %" PRIu64 "\n", FLAGS_ops_per_thread);
    printf("Cache size          : %" PRIu64 "\n", FLAGS_cache_size);
-    printf("Num shard bits      : %d\n", FLAGS_num_shard_bits);
-    printf("Max key             : %" PRIu64 "\n", FLAGS_max_key);
-    printf("Populate cache      : %d\n", FLAGS_populate_cache);
-    printf("Insert percentage   : %d%%\n", FLAGS_insert_percent);
-    printf("Lookup percentage   : %d%%\n", FLAGS_lookup_percent);
-    printf("Erase percentage    : %d%%\n", FLAGS_erase_percent);
+    printf("Num shard bits      : %u\n", FLAGS_num_shard_bits);
+    printf("Max key             : %" PRIu64 "\n", max_key_);
+    printf("Resident ratio      : %g\n", FLAGS_resident_ratio);
+    printf("Skew degree         : %u\n", FLAGS_skew);
+    printf("Populate cache      : %d\n", int{FLAGS_populate_cache});
+    printf("Lookup+Insert pct   : %u%%\n", FLAGS_lookup_insert_percent);
+    printf("Insert percentage   : %u%%\n", FLAGS_insert_percent);
+    printf("Lookup percentage   : %u%%\n", FLAGS_lookup_percent);
+    printf("Erase percentage    : %u%%\n", FLAGS_erase_percent);
    printf("----------------------------\n");
  }
 };
@@ -270,6 +368,8 @@ int main(int argc, char** argv) {
  ROCKSDB_NAMESPACE::CacheBench bench;
  if (FLAGS_populate_cache) {
    bench.PopulateCache();
+    printf("Population complete\n");
+    printf("----------------------------\n");
  }
  if (bench.Run()) {
    return 0;
@@ -341,7 +341,8 @@ class ClockCacheShard final : public CacheShard {
  CacheHandle* Insert(const Slice& key, uint32_t hash, void* value,
                      size_t change,
                      void (*deleter)(const Slice& key, void* value),
-                      bool hold_reference, CleanupContext* context);
+                      bool hold_reference, CleanupContext* context,
+                      bool* overwritten);

  // Guards list_, head_, and recycle_. In addition, updating table_ also has
  // to hold the mutex, to avoid the cache being in inconsistent state.
@@ -564,7 +565,8 @@ void ClockCacheShard::SetStrictCapacityLimit(bool strict_capacity_limit) {
 CacheHandle* ClockCacheShard::Insert(
    const Slice& key, uint32_t hash, void* value, size_t charge,
    void (*deleter)(const Slice& key, void* value), bool hold_reference,
-    CleanupContext* context) {
+    CleanupContext* context, bool* overwritten) {
+  assert(overwritten != nullptr && *overwritten == false);
  size_t total_charge =
      CacheHandle::CalcTotalCharge(key, charge, metadata_charge_policy_);
  MutexLock l(&mutex_);
@@ -597,6 +599,7 @@ CacheHandle* ClockCacheShard::Insert(
  handle->flags.store(flags, std::memory_order_relaxed);
  HashTable::accessor accessor;
  if (table_.find(accessor, CacheKey(key, hash))) {
+    *overwritten = true;
    CacheHandle* existing_handle = accessor->second;
    table_.erase(accessor);
    UnsetInCache(existing_handle, context);
@@ -619,8 +622,9 @@ Status ClockCacheShard::Insert(const Slice& key, uint32_t hash, void* value,
  char* key_data = new char[key.size()];
  memcpy(key_data, key.data(), key.size());
  Slice key_copy(key_data, key.size());
+  bool overwritten = false;
  CacheHandle* handle = Insert(key_copy, hash, value, charge, deleter,
-                               out_handle != nullptr, &context);
+                               out_handle != nullptr, &context, &overwritten);
  Status s;
  if (out_handle != nullptr) {
    if (handle == nullptr) {
@@ -629,6 +633,10 @@ Status ClockCacheShard::Insert(const Slice& key, uint32_t hash, void* value,
      *out_handle = reinterpret_cast<Cache::Handle*>(handle);
    }
  }
+  if (overwritten) {
+    assert(s.ok());
+    s = Status::OkOverwritten();
+  }
  Cleanup(context);
  return s;
 }
@@ -386,6 +386,7 @@ Status LRUCacheShard::Insert(const Slice& key, uint32_t hash, void* value,
      LRUHandle* old = table_.Insert(e);
      usage_ += total_charge;
      if (old != nullptr) {
+        s = Status::OkOverwritten();
        assert(old->InCache());
        old->SetInCache(false);
        if (!old->HasRefs()) {
@@ -0,0 +1,7 @@
+macro(get_cxx_std_flags FLAGS_VARIABLE)
+  if( CMAKE_CXX_STANDARD_REQUIRED )
+    set(${FLAGS_VARIABLE} ${CMAKE_CXX${CMAKE_CXX_STANDARD}_STANDARD_COMPILE_OPTION})
+  else()
+    set(${FLAGS_VARIABLE} ${CMAKE_CXX${CMAKE_CXX_STANDARD}_EXTENSION_COMPILE_OPTION})
+  endif()
+endmacro()
@@ -75,7 +75,7 @@ Status ArenaWrappedDBIter::Refresh() {

    InternalIterator* internal_iter = db_impl_->NewInternalIterator(
        read_options_, cfd_, sv, &arena_, db_iter_->GetRangeDelAggregator(),
-        latest_seq);
+        latest_seq, /* allow_unprepared_value */ true);
    SetIterUnderDBIter(internal_iter);
  } else {
    db_iter_->set_sequence(latest_seq);
@@ -10,10 +10,6 @@

 namespace ROCKSDB_NAMESPACE {

-SharedBlobFileMetaData::~SharedBlobFileMetaData() {
-  // TODO: add the blob file to the list of obsolete files here
-}
-
 std::string SharedBlobFileMetaData::DebugString() const {
  std::ostringstream oss;
  oss << (*this);
@@ -23,6 +23,42 @@ namespace ROCKSDB_NAMESPACE {

 class SharedBlobFileMetaData {
 public:
+  static std::shared_ptr<SharedBlobFileMetaData> Create(
+      uint64_t blob_file_number, uint64_t total_blob_count,
+      uint64_t total_blob_bytes, std::string checksum_method,
+      std::string checksum_value) {
+    return std::shared_ptr<SharedBlobFileMetaData>(new SharedBlobFileMetaData(
+        blob_file_number, total_blob_count, total_blob_bytes,
+        std::move(checksum_method), std::move(checksum_value)));
+  }
+
+  template <typename Deleter>
+  static std::shared_ptr<SharedBlobFileMetaData> Create(
+      uint64_t blob_file_number, uint64_t total_blob_count,
+      uint64_t total_blob_bytes, std::string checksum_method,
+      std::string checksum_value, Deleter deleter) {
+    return std::shared_ptr<SharedBlobFileMetaData>(
+        new SharedBlobFileMetaData(blob_file_number, total_blob_count,
+                                   total_blob_bytes, std::move(checksum_method),
+                                   std::move(checksum_value)),
+        deleter);
+  }
+
+  SharedBlobFileMetaData(const SharedBlobFileMetaData&) = delete;
+  SharedBlobFileMetaData& operator=(const SharedBlobFileMetaData&) = delete;
+
+  SharedBlobFileMetaData(SharedBlobFileMetaData&&) = delete;
+  SharedBlobFileMetaData& operator=(SharedBlobFileMetaData&&) = delete;
+
+  uint64_t GetBlobFileNumber() const { return blob_file_number_; }
+  uint64_t GetTotalBlobCount() const { return total_blob_count_; }
+  uint64_t GetTotalBlobBytes() const { return total_blob_bytes_; }
+  const std::string& GetChecksumMethod() const { return checksum_method_; }
+  const std::string& GetChecksumValue() const { return checksum_value_; }
+
+  std::string DebugString() const;
+
+ private:
  SharedBlobFileMetaData(uint64_t blob_file_number, uint64_t total_blob_count,
                         uint64_t total_blob_bytes, std::string checksum_method,
                         std::string checksum_value)
@@ -34,20 +70,6 @@ class SharedBlobFileMetaData {
    assert(checksum_method_.empty() == checksum_value_.empty());
  }

-  ~SharedBlobFileMetaData();
-
-  SharedBlobFileMetaData(const SharedBlobFileMetaData&) = delete;
-  SharedBlobFileMetaData& operator=(const SharedBlobFileMetaData&) = delete;
-
-  uint64_t GetBlobFileNumber() const { return blob_file_number_; }
-  uint64_t GetTotalBlobCount() const { return total_blob_count_; }
-  uint64_t GetTotalBlobBytes() const { return total_blob_bytes_; }
-  const std::string& GetChecksumMethod() const { return checksum_method_; }
-  const std::string& GetChecksumValue() const { return checksum_value_; }
-
-  std::string DebugString() const;
-
- private:
  uint64_t blob_file_number_;
  uint64_t total_blob_count_;
  uint64_t total_blob_bytes_;
@@ -68,21 +90,19 @@ std::ostream& operator<<(std::ostream& os,

 class BlobFileMetaData {
 public:
-  BlobFileMetaData(std::shared_ptr<SharedBlobFileMetaData> shared_meta,
-                   uint64_t garbage_blob_count, uint64_t garbage_blob_bytes)
-      : shared_meta_(std::move(shared_meta)),
-        garbage_blob_count_(garbage_blob_count),
-        garbage_blob_bytes_(garbage_blob_bytes) {
-    assert(shared_meta_);
-    assert(garbage_blob_count_ <= shared_meta_->GetTotalBlobCount());
-    assert(garbage_blob_bytes_ <= shared_meta_->GetTotalBlobBytes());
+  static std::shared_ptr<BlobFileMetaData> Create(
+      std::shared_ptr<SharedBlobFileMetaData> shared_meta,
+      uint64_t garbage_blob_count, uint64_t garbage_blob_bytes) {
+    return std::shared_ptr<BlobFileMetaData>(new BlobFileMetaData(
+        std::move(shared_meta), garbage_blob_count, garbage_blob_bytes));
  }

-  ~BlobFileMetaData() = default;
-
  BlobFileMetaData(const BlobFileMetaData&) = delete;
  BlobFileMetaData& operator=(const BlobFileMetaData&) = delete;

+  BlobFileMetaData(BlobFileMetaData&&) = delete;
+  BlobFileMetaData& operator=(BlobFileMetaData&&) = delete;
+
  const std::shared_ptr<SharedBlobFileMetaData>& GetSharedMeta() const {
    return shared_meta_;
  }
@@ -114,6 +134,16 @@ class BlobFileMetaData {
  std::string DebugString() const;

 private:
+  BlobFileMetaData(std::shared_ptr<SharedBlobFileMetaData> shared_meta,
+                   uint64_t garbage_blob_count, uint64_t garbage_blob_bytes)
+      : shared_meta_(std::move(shared_meta)),
+        garbage_blob_count_(garbage_blob_count),
+        garbage_blob_bytes_(garbage_blob_bytes) {
+    assert(shared_meta_);
+    assert(garbage_blob_count_ <= shared_meta_->GetTotalBlobCount());
+    assert(garbage_blob_bytes_ <= shared_meta_->GetTotalBlobBytes());
+  }
+
  std::shared_ptr<SharedBlobFileMetaData> shared_meta_;
  uint64_t garbage_blob_count_;
  uint64_t garbage_blob_bytes_;
@@ -183,8 +183,7 @@ Status BuildTable(
    }

    // Finish and check for builder errors
-    tp = builder->GetTableProperties();
-    bool empty = builder->NumEntries() == 0 && tp.num_range_deletions == 0;
+    bool empty = builder->IsEmpty();
    s = c_iter.status();
    TEST_SYNC_POINT("BuildTable:BeforeFinishBuildTable");
    if (!s.ok() || empty) {
@@ -241,7 +240,8 @@ Status BuildTable(
                                      : internal_stats->GetFileReadHist(0),
          TableReaderCaller::kFlush, /*arena=*/nullptr,
          /*skip_filter=*/false, level, /*smallest_compaction_key=*/nullptr,
-          /*largest_compaction_key*/ nullptr));
+          /*largest_compaction_key*/ nullptr,
+          /*allow_unprepared_value*/ false));
      s = it->status();
      if (s.ok() && paranoid_file_checks) {
        for (it->SeekToFirst(); it->Valid(); it->Next()) {
@@ -4441,6 +4441,16 @@ uint64_t rocksdb_approximate_memory_usage_get_cache_total(
  return memory_usage->cache_total;
 }

+void rocksdb_options_set_dump_malloc_stats(rocksdb_options_t* opt,
+                                           unsigned char val) {
+  opt->rep.dump_malloc_stats = val;
+}
+
+void rocksdb_options_set_memtable_whole_key_filtering(rocksdb_options_t* opt,
+                                                      unsigned char val) {
+  opt->rep.memtable_whole_key_filtering = val;
+}
+
 // deletes container with memory usage estimates
 void rocksdb_approximate_memory_usage_destroy(rocksdb_memory_usage_t* usage) {
  delete usage;
@@ -8,16 +8,16 @@
 // found in the LICENSE file. See the AUTHORS file for names of contributors.

 #include <algorithm>
-#include <vector>
 #include <string>
 #include <thread>
+#include <vector>

 #include "db/db_impl/db_impl.h"
 #include "db/db_test_util.h"
-#include "memtable/hash_skiplist_rep.h"
 #include "options/options_parser.h"
 #include "port/port.h"
 #include "port/stack_trace.h"
+#include "rocksdb/convenience.h"
 #include "rocksdb/db.h"
 #include "rocksdb/env.h"
 #include "rocksdb/iterator.h"
@@ -287,7 +287,9 @@ class ColumnFamilyTestBase : public testing::Test {
      // Verify the CF options of the returned CF handle.
      ColumnFamilyDescriptor desc;
      ASSERT_OK(handles_[cfi]->GetDescriptor(&desc));
-      RocksDBOptionsParser::VerifyCFOptions(desc.options, current_cf_opt);
+      RocksDBOptionsParser::VerifyCFOptions(ConfigOptions(), desc.options,
+                                            current_cf_opt);
+
 #endif  // !ROCKSDB_LITE
      cfi++;
    }
@@ -23,7 +23,7 @@ const uint64_t kRangeTombstoneSentinel =

 int sstableKeyCompare(const Comparator* user_cmp, const InternalKey& a,
                      const InternalKey& b) {
-  auto c = user_cmp->Compare(a.user_key(), b.user_key());
+  auto c = user_cmp->CompareWithoutTimestamp(a.user_key(), b.user_key());
  if (c != 0) {
    return c;
  }
@@ -655,7 +655,8 @@ Status CompactionJob::Run() {
            TableReaderCaller::kCompactionRefill, /*arena=*/nullptr,
            /*skip_filters=*/false, compact_->compaction->output_level(),
            /*smallest_compaction_key=*/nullptr,
-            /*largest_compaction_key=*/nullptr);
+            /*largest_compaction_key=*/nullptr,
+            /*allow_unprepared_value=*/false);
        auto s = iter->status();

        if (s.ok() && paranoid_file_checks_) {
@@ -937,7 +938,8 @@ void CompactionJob::ProcessKeyValueCompaction(SubcompactionState* sub_compact) {
    assert(sub_compact->builder != nullptr);
    assert(sub_compact->current_output() != nullptr);
    sub_compact->builder->Add(key, value);
-    sub_compact->current_output_file_size = sub_compact->builder->FileSize();
+    sub_compact->current_output_file_size =
+        sub_compact->builder->EstimatedFileSize();
    const ParsedInternalKey& ikey = c_iter->ikey();
    sub_compact->current_output()->meta.UpdateBoundaries(
        key, value, ikey.sequence, ikey.type);
@@ -71,6 +71,7 @@ Compaction* FIFOCompactionPicker::PickTTLCompaction(
  if (current_time > mutable_cf_options.ttl) {
    for (auto ritr = level_files.rbegin(); ritr != level_files.rend(); ++ritr) {
      FileMetaData* f = *ritr;
+      assert(f);
      if (f->fd.table_reader && f->fd.table_reader->GetTableProperties()) {
        uint64_t creation_time =
            f->fd.table_reader->GetTableProperties()->creation_time;
@@ -96,7 +97,8 @@ Compaction* FIFOCompactionPicker::PickTTLCompaction(

  for (const auto& f : inputs[0].files) {
    uint64_t creation_time = 0;
-    if (f && f->fd.table_reader && f->fd.table_reader->GetTableProperties()) {
+    assert(f);
+    if (f->fd.table_reader && f->fd.table_reader->GetTableProperties()) {
      creation_time = f->fd.table_reader->GetTableProperties()->creation_time;
    }
    ROCKS_LOG_BUFFER(log_buffer,
@@ -93,9 +93,13 @@ class LevelCompactionBuilder {
  // otherwise, returns false.
  bool PickIntraL0Compaction();

-  void PickExpiredTtlFiles();
-
-  void PickFilesMarkedForPeriodicCompaction();
+  // Picks a file from level_files to compact.
+  // level_files is a vector of (level, file metadata) in ascending order of
+  // level. If compact_to_next_level is true, compact the file to the next
+  // level, otherwise, compact to the same level as the input file.
+  void PickFileToCompact(
+      const autovector<std::pair<int, FileMetaData*>>& level_files,
+      bool compact_to_next_level);

  const std::string& cf_name_;
  VersionStorageInfo* vstorage_;
@@ -124,72 +128,34 @@ class LevelCompactionBuilder {
  static const int kMinFilesForIntraL0Compaction = 4;
 };

-void LevelCompactionBuilder::PickExpiredTtlFiles() {
-  if (vstorage_->ExpiredTtlFiles().empty()) {
-    return;
-  }
-
-  auto continuation = [&](std::pair<int, FileMetaData*> level_file) {
+void LevelCompactionBuilder::PickFileToCompact(
+    const autovector<std::pair<int, FileMetaData*>>& level_files,
+    bool compact_to_next_level) {
+  for (auto& level_file : level_files) {
    // If it's being compacted it has nothing to do here.
    // If this assert() fails that means that some function marked some
    // files as being_compacted, but didn't call ComputeCompactionScore()
    assert(!level_file.second->being_compacted);
    start_level_ = level_file.first;
-    output_level_ =
-        (start_level_ == 0) ? vstorage_->base_level() : start_level_ + 1;
-
-    if ((start_level_ == vstorage_->num_non_empty_levels() - 1) ||
+    if ((compact_to_next_level &&
+         start_level_ == vstorage_->num_non_empty_levels() - 1) ||
        (start_level_ == 0 &&
         !compaction_picker_->level0_compactions_in_progress()->empty())) {
-      return false;
+      continue;
+    }
+    if (compact_to_next_level) {
+      output_level_ =
+          (start_level_ == 0) ? vstorage_->base_level() : start_level_ + 1;
+    } else {
+      output_level_ = start_level_;
    }
-
    start_level_inputs_.files = {level_file.second};
    start_level_inputs_.level = start_level_;
-    return compaction_picker_->ExpandInputsToCleanCut(cf_name_, vstorage_,
-                                                      &start_level_inputs_);
-  };
-
-  for (auto& level_file : vstorage_->ExpiredTtlFiles()) {
-    if (continuation(level_file)) {
-      // found the compaction!
+    if (compaction_picker_->ExpandInputsToCleanCut(cf_name_, vstorage_,
+                                                   &start_level_inputs_)) {
      return;
    }
  }
-
-  start_level_inputs_.files.clear();
-}
-
-void LevelCompactionBuilder::PickFilesMarkedForPeriodicCompaction() {
-  if (vstorage_->FilesMarkedForPeriodicCompaction().empty()) {
-    return;
-  }
-
-  auto continuation = [&](std::pair<int, FileMetaData*> level_file) {
-    // If it's being compacted it has nothing to do here.
-    // If this assert() fails that means that some function marked some
-    // files as being_compacted, but didn't call ComputeCompactionScore()
-    assert(!level_file.second->being_compacted);
-    output_level_ = start_level_ = level_file.first;
-
-    if (start_level_ == 0 &&
-        !compaction_picker_->level0_compactions_in_progress()->empty()) {
-      return false;
-    }
-
-    start_level_inputs_.files = {level_file.second};
-    start_level_inputs_.level = start_level_;
-    return compaction_picker_->ExpandInputsToCleanCut(cf_name_, vstorage_,
-                                                      &start_level_inputs_);
-  };
-
-  for (auto& level_file : vstorage_->FilesMarkedForPeriodicCompaction()) {
-    if (continuation(level_file)) {
-      // found the compaction!
-      return;
-    }
-  }
-
  start_level_inputs_.files.clear();
 }

@@ -238,63 +204,46 @@ void LevelCompactionBuilder::SetupInitialFiles() {
          }
        }
      }
+    } else {
+      // Compaction scores are sorted in descending order, no further scores
+      // will be >= 1.
+      break;
    }
  }
+  if (!start_level_inputs_.empty()) {
+    return;
+  }

  // if we didn't find a compaction, check if there are any files marked for
  // compaction
-  if (start_level_inputs_.empty()) {
-    parent_index_ = base_index_ = -1;
+  parent_index_ = base_index_ = -1;

-    compaction_picker_->PickFilesMarkedForCompaction(
-        cf_name_, vstorage_, &start_level_, &output_level_,
-        &start_level_inputs_);
-    if (!start_level_inputs_.empty()) {
-      compaction_reason_ = CompactionReason::kFilesMarkedForCompaction;
-      return;
-    }
+  compaction_picker_->PickFilesMarkedForCompaction(
+      cf_name_, vstorage_, &start_level_, &output_level_, &start_level_inputs_);
+  if (!start_level_inputs_.empty()) {
+    compaction_reason_ = CompactionReason::kFilesMarkedForCompaction;
+    return;
  }

  // Bottommost Files Compaction on deleting tombstones
-  if (start_level_inputs_.empty()) {
-    size_t i;
-    for (i = 0; i < vstorage_->BottommostFilesMarkedForCompaction().size();
-         ++i) {
-      auto& level_and_file = vstorage_->BottommostFilesMarkedForCompaction()[i];
-      assert(!level_and_file.second->being_compacted);
-      start_level_inputs_.level = output_level_ = start_level_ =
-          level_and_file.first;
-      start_level_inputs_.files = {level_and_file.second};
-      if (compaction_picker_->ExpandInputsToCleanCut(cf_name_, vstorage_,
-                                                     &start_level_inputs_)) {
-        break;
-      }
-    }
-    if (i == vstorage_->BottommostFilesMarkedForCompaction().size()) {
-      start_level_inputs_.clear();
-    } else {
-      assert(!start_level_inputs_.empty());
-      compaction_reason_ = CompactionReason::kBottommostFiles;
-      return;
-    }
+  PickFileToCompact(vstorage_->BottommostFilesMarkedForCompaction(), false);
+  if (!start_level_inputs_.empty()) {
+    compaction_reason_ = CompactionReason::kBottommostFiles;
+    return;
  }

  // TTL Compaction
-  if (start_level_inputs_.empty()) {
-    PickExpiredTtlFiles();
-    if (!start_level_inputs_.empty()) {
-      compaction_reason_ = CompactionReason::kTtl;
-      return;
-    }
+  PickFileToCompact(vstorage_->ExpiredTtlFiles(), true);
+  if (!start_level_inputs_.empty()) {
+    compaction_reason_ = CompactionReason::kTtl;
+    return;
  }

  // Periodic Compaction
-  if (start_level_inputs_.empty()) {
-    PickFilesMarkedForPeriodicCompaction();
-    if (!start_level_inputs_.empty()) {
-      compaction_reason_ = CompactionReason::kPeriodicCompaction;
-      return;
-    }
+  PickFileToCompact(vstorage_->FilesMarkedForPeriodicCompaction(), false);
+  if (!start_level_inputs_.empty()) {
+    compaction_reason_ = CompactionReason::kPeriodicCompaction;
+    return;
  }
 }

@@ -389,7 +389,7 @@ Compaction* UniversalCompactionBuilder::PickCompaction() {
  VersionStorageInfo::LevelSummaryStorage tmp;
  ROCKS_LOG_BUFFER_MAX_SZ(
      log_buffer_, 3072,
-      "[%s] Universal: sorted runs files(%" ROCKSDB_PRIszt "): %s\n",
+      "[%s] Universal: sorted runs: %" ROCKSDB_PRIszt " files: %s\n",
      cf_name_.c_str(), sorted_runs_.size(), vstorage_->LevelSummary(&tmp));

  Compaction* c = nullptr;
@@ -14,7 +14,7 @@
 namespace ROCKSDB_NAMESPACE {

 void CancelAllBackgroundWork(DB* db, bool wait) {
-  (static_cast_with_check<DBImpl, DB>(db->GetRootDB()))
+  (static_cast_with_check<DBImpl>(db->GetRootDB()))
      ->CancelAllBackgroundWork(wait);
 }

@@ -28,7 +28,7 @@ Status DeleteFilesInRange(DB* db, ColumnFamilyHandle* column_family,
 Status DeleteFilesInRanges(DB* db, ColumnFamilyHandle* column_family,
                           const RangePtr* ranges, size_t n,
                           bool include_end) {
-  return (static_cast_with_check<DBImpl, DB>(db->GetRootDB()))
+  return (static_cast_with_check<DBImpl>(db->GetRootDB()))
      ->DeleteFilesInRanges(column_family, ranges, n, include_end);
 }

@@ -1774,6 +1774,28 @@ TEST_F(DBBasicTest, IncrementalRecoveryNoCorrupt) {
  }
 }

+TEST_F(DBBasicTest, BestEffortsRecoveryWithVersionBuildingFailure) {
+  Options options = CurrentOptions();
+  DestroyAndReopen(options);
+  ASSERT_OK(Put("foo", "value"));
+  ASSERT_OK(Flush());
+  SyncPoint::GetInstance()->DisableProcessing();
+  SyncPoint::GetInstance()->ClearAllCallBacks();
+  SyncPoint::GetInstance()->SetCallBack(
+      "VersionBuilder::CheckConsistencyBeforeReturn", [&](void* arg) {
+        ASSERT_NE(nullptr, arg);
+        *(reinterpret_cast<Status*>(arg)) =
+            Status::Corruption("Inject corruption");
+      });
+  SyncPoint::GetInstance()->EnableProcessing();
+
+  options.best_efforts_recovery = true;
+  Status s = TryReopen(options);
+  ASSERT_TRUE(s.IsCorruption());
+  SyncPoint::GetInstance()->DisableProcessing();
+  SyncPoint::GetInstance()->ClearAllCallBacks();
+}
+
 #ifndef ROCKSDB_LITE
 namespace {
 class TableFileListener : public EventListener {
@@ -1850,6 +1872,29 @@ TEST_F(DBBasicTest, RecoverWithMissingFiles) {
  }
 }

+TEST_F(DBBasicTest, RecoverWithNoCurrentFile) {
+  Options options = CurrentOptions();
+  options.env = env_;
+  DestroyAndReopen(options);
+  CreateAndReopenWithCF({"pikachu"}, options);
+  options.best_efforts_recovery = true;
+  ReopenWithColumnFamilies({kDefaultColumnFamilyName, "pikachu"}, options);
+  ASSERT_EQ(2, handles_.size());
+  ASSERT_OK(Put("foo", "value"));
+  ASSERT_OK(Put(1, "bar", "value"));
+  ASSERT_OK(Flush());
+  ASSERT_OK(Flush(1));
+  Close();
+  ASSERT_OK(env_->DeleteFile(CurrentFileName(dbname_)));
+  ReopenWithColumnFamilies({kDefaultColumnFamilyName, "pikachu"}, options);
+  std::vector<std::string> cf_names;
+  ASSERT_OK(DB::ListColumnFamilies(DBOptions(options), dbname_, &cf_names));
+  ASSERT_EQ(2, cf_names.size());
+  for (const auto& name : cf_names) {
+    ASSERT_TRUE(name == kDefaultColumnFamilyName || name == "pikachu");
+  }
+}
+
 TEST_F(DBBasicTest, SkipWALIfMissingTableFiles) {
  Options options = CurrentOptions();
  DestroyAndReopen(options);
@@ -1890,15 +1935,14 @@ TEST_F(DBBasicTest, SkipWALIfMissingTableFiles) {
 }
 #endif  // !ROCKSDB_LITE

-class DBBasicTestWithParallelIO
-    : public DBTestBase,
-      public testing::WithParamInterface<std::tuple<bool, bool, bool, bool>> {
+class DBBasicTestMultiGet : public DBTestBase {
 public:
-  DBBasicTestWithParallelIO() : DBTestBase("/db_basic_test_with_parallel_io") {
-    bool compressed_cache = std::get<0>(GetParam());
-    bool uncompressed_cache = std::get<1>(GetParam());
-    compression_enabled_ = std::get<2>(GetParam());
-    fill_cache_ = std::get<3>(GetParam());
+  DBBasicTestMultiGet(std::string test_dir, int num_cfs, bool compressed_cache,
+                      bool uncompressed_cache, bool compression_enabled,
+                      bool fill_cache, uint32_t compression_parallel_threads)
+      : DBTestBase(test_dir) {
+    compression_enabled_ = compression_enabled;
+    fill_cache_ = fill_cache;

    if (compressed_cache) {
      std::shared_ptr<Cache> cache = NewLRUCache(1048576);
@@ -1953,25 +1997,48 @@ class DBBasicTestWithParallelIO
    options.table_factory.reset(new BlockBasedTableFactory(table_options));
    if (!compression_enabled_) {
      options.compression = kNoCompression;
+    } else {
+      options.compression_opts.parallel_threads = compression_parallel_threads;
    }
    Reopen(options);

-    std::string zero_str(128, '\0');
-    for (int i = 0; i < 100; ++i) {
-      // Make the value compressible. A purely random string doesn't compress
-      // and the resultant data block will not be compressed
-      values_.emplace_back(RandomString(&rnd, 128) + zero_str);
-      assert(Put(Key(i), values_[i]) == Status::OK());
+    if (num_cfs > 1) {
+      for (int cf = 0; cf < num_cfs; ++cf) {
+        cf_names_.emplace_back("cf" + std::to_string(cf));
+      }
+      CreateColumnFamilies(cf_names_, options);
+      cf_names_.emplace_back("default");
    }
-    Flush();

-    for (int i = 0; i < 100; ++i) {
-      // block cannot gain space by compression
-      uncompressable_values_.emplace_back(RandomString(&rnd, 256) + '\0');
-      std::string tmp_key = "a" + Key(i);
-      assert(Put(tmp_key, uncompressable_values_[i]) == Status::OK());
+    std::string zero_str(128, '\0');
+    for (int cf = 0; cf < num_cfs; ++cf) {
+      for (int i = 0; i < 100; ++i) {
+        // Make the value compressible. A purely random string doesn't compress
+        // and the resultant data block will not be compressed
+        values_.emplace_back(RandomString(&rnd, 128) + zero_str);
+        assert(((num_cfs == 1) ? Put(Key(i), values_[i])
+                               : Put(cf, Key(i), values_[i])) == Status::OK());
+      }
+      if (num_cfs == 1) {
+        Flush();
+      } else {
+        dbfull()->Flush(FlushOptions(), handles_[cf]);
+      }
+
+      for (int i = 0; i < 100; ++i) {
+        // block cannot gain space by compression
+        uncompressable_values_.emplace_back(RandomString(&rnd, 256) + '\0');
+        std::string tmp_key = "a" + Key(i);
+        assert(((num_cfs == 1) ? Put(tmp_key, uncompressable_values_[i])
+                               : Put(cf, tmp_key, uncompressable_values_[i])) ==
+               Status::OK());
+      }
+      if (num_cfs == 1) {
+        Flush();
+      } else {
+        dbfull()->Flush(FlushOptions(), handles_[cf]);
+      }
    }
-    Flush();
  }

  bool CheckValue(int i, const std::string& value) {
@@ -1988,6 +2055,8 @@ class DBBasicTestWithParallelIO
    return false;
  }

+  const std::vector<std::string>& GetCFNames() const { return cf_names_; }
+
  int num_lookups() { return uncompressed_cache_->num_lookups(); }
  int num_found() { return uncompressed_cache_->num_found(); }
  int num_inserts() { return uncompressed_cache_->num_inserts(); }
@@ -2004,7 +2073,7 @@ class DBBasicTestWithParallelIO
  static void SetUpTestCase() {}
  static void TearDownTestCase() {}

- private:
+ protected:
  class MyFlushBlockPolicyFactory : public FlushBlockPolicyFactory {
   public:
    MyFlushBlockPolicyFactory() {}
@@ -2045,23 +2114,25 @@ class DBBasicTestWithParallelIO
    const BlockBuilder& data_block_builder_;
  };

-  class MyBlockCache : public Cache {
+  class MyBlockCache : public CacheWrapper {
   public:
-    explicit MyBlockCache(std::shared_ptr<Cache>& target)
-        : target_(target), num_lookups_(0), num_found_(0), num_inserts_(0) {}
+    explicit MyBlockCache(std::shared_ptr<Cache> target)
+        : CacheWrapper(target),
+          num_lookups_(0),
+          num_found_(0),
+          num_inserts_(0) {}

-    virtual const char* Name() const override { return "MyBlockCache"; }
+    const char* Name() const override { return "MyBlockCache"; }

-    virtual Status Insert(const Slice& key, void* value, size_t charge,
-                          void (*deleter)(const Slice& key, void* value),
-                          Handle** handle = nullptr,
-                          Priority priority = Priority::LOW) override {
+    Status Insert(const Slice& key, void* value, size_t charge,
+                  void (*deleter)(const Slice& key, void* value),
+                  Handle** handle = nullptr,
+                  Priority priority = Priority::LOW) override {
      num_inserts_++;
      return target_->Insert(key, value, charge, deleter, handle, priority);
    }

-    virtual Handle* Lookup(const Slice& key,
-                           Statistics* stats = nullptr) override {
+    Handle* Lookup(const Slice& key, Statistics* stats = nullptr) override {
      num_lookups_++;
      Handle* handle = target_->Lookup(key, stats);
      if (handle != nullptr) {
@@ -2069,57 +2140,6 @@ class DBBasicTestWithParallelIO
      }
      return handle;
    }
-
-    virtual bool Ref(Handle* handle) override { return target_->Ref(handle); }
-
-    virtual bool Release(Handle* handle, bool force_erase = false) override {
-      return target_->Release(handle, force_erase);
-    }
-
-    virtual void* Value(Handle* handle) override {
-      return target_->Value(handle);
-    }
-
-    virtual void Erase(const Slice& key) override { target_->Erase(key); }
-    virtual uint64_t NewId() override { return target_->NewId(); }
-
-    virtual void SetCapacity(size_t capacity) override {
-      target_->SetCapacity(capacity);
-    }
-
-    virtual void SetStrictCapacityLimit(bool strict_capacity_limit) override {
-      target_->SetStrictCapacityLimit(strict_capacity_limit);
-    }
-
-    virtual bool HasStrictCapacityLimit() const override {
-      return target_->HasStrictCapacityLimit();
-    }
-
-    virtual size_t GetCapacity() const override {
-      return target_->GetCapacity();
-    }
-
-    virtual size_t GetUsage() const override { return target_->GetUsage(); }
-
-    virtual size_t GetUsage(Handle* handle) const override {
-      return target_->GetUsage(handle);
-    }
-
-    virtual size_t GetPinnedUsage() const override {
-      return target_->GetPinnedUsage();
-    }
-
-    virtual size_t GetCharge(Handle* /*handle*/) const override { return 0; }
-
-    virtual void ApplyToAllCacheEntries(void (*callback)(void*, size_t),
-                                        bool thread_safe) override {
-      return target_->ApplyToAllCacheEntries(callback, thread_safe);
-    }
-
-    virtual void EraseUnRefEntries() override {
-      return target_->EraseUnRefEntries();
-    }
-
    int num_lookups() { return num_lookups_; }

    int num_found() { return num_found_; }
@@ -2127,7 +2147,6 @@ class DBBasicTestWithParallelIO
    int num_inserts() { return num_inserts_; }

   private:
-    std::shared_ptr<Cache> target_;
    int num_lookups_;
    int num_found_;
    int num_inserts_;
@@ -2139,6 +2158,19 @@ class DBBasicTestWithParallelIO
  std::vector<std::string> values_;
  std::vector<std::string> uncompressable_values_;
  bool fill_cache_;
+  std::vector<std::string> cf_names_;
+};
+
+class DBBasicTestWithParallelIO
+    : public DBBasicTestMultiGet,
+      public testing::WithParamInterface<
+          std::tuple<bool, bool, bool, bool, uint32_t>> {
+ public:
+  DBBasicTestWithParallelIO()
+      : DBBasicTestMultiGet("/db_basic_test_with_parallel_io", 1,
+                            std::get<0>(GetParam()), std::get<1>(GetParam()),
+                            std::get<2>(GetParam()), std::get<3>(GetParam()),
+                            std::get<4>(GetParam())) {}
 };

 TEST_P(DBBasicTestWithParallelIO, MultiGet) {
@@ -2354,10 +2386,282 @@ INSTANTIATE_TEST_CASE_P(ParallelIO, DBBasicTestWithParallelIO,
                        // Param 1 - Uncompressed cache enabled
                        // Param 2 - Data compression enabled
                        // Param 3 - ReadOptions::fill_cache
+                        // Param 4 - CompressionOptions::parallel_threads
                        ::testing::Combine(::testing::Bool(), ::testing::Bool(),
-                                           ::testing::Bool(),
-                                           ::testing::Bool()));
+                                           ::testing::Bool(), ::testing::Bool(),
+                                           ::testing::Values(1, 4)));

+// A test class for intercepting random reads and injecting artificial
+// delays. Used for testing the deadline/timeout feature
+class DBBasicTestMultiGetDeadline : public DBBasicTestMultiGet {
+ public:
+  DBBasicTestMultiGetDeadline()
+      : DBBasicTestMultiGet("db_basic_test_multiget_deadline" /*Test dir*/,
+                             10 /*# of column families*/,
+                             false /*compressed cache enabled*/,
+                             true /*uncompressed cache enabled*/,
+                             true /*compression enabled*/,
+                             true /*ReadOptions.fill_cache*/,
+                             1 /*# of parallel compression threads*/) {}
+
+  // Forward declaration
+  class DeadlineFS;
+
+  class DeadlineRandomAccessFile : public FSRandomAccessFileWrapper {
+   public:
+    DeadlineRandomAccessFile(DeadlineFS& fs, SpecialEnv* env,
+                             std::unique_ptr<FSRandomAccessFile>& file)
+        : FSRandomAccessFileWrapper(file.get()),
+          fs_(fs),
+          file_(std::move(file)),
+          env_(env) {}
+
+    IOStatus Read(uint64_t offset, size_t len, const IOOptions& opts,
+          Slice* result, char* scratch, IODebugContext* dbg) const override {
+      int delay;
+      const std::chrono::microseconds deadline = fs_.GetDeadline();
+      if (deadline.count()) {
+        AssertDeadline(deadline, opts);
+      }
+      if (fs_.ShouldDelay(&delay)) {
+        env_->SleepForMicroseconds(delay);
+      }
+      return FSRandomAccessFileWrapper::Read(offset, len, opts, result, scratch,
+                                             dbg);
+    }
+
+    IOStatus MultiRead(FSReadRequest* reqs, size_t num_reqs,
+          const IOOptions& options, IODebugContext* dbg) override {
+      int delay;
+      const std::chrono::microseconds deadline = fs_.GetDeadline();
+      if (deadline.count()) {
+        AssertDeadline(deadline, options);
+      }
+      if (fs_.ShouldDelay(&delay)) {
+        env_->SleepForMicroseconds(delay);
+      }
+      return FSRandomAccessFileWrapper::MultiRead(reqs, num_reqs, options, dbg);
+    }
+
+   private:
+    void AssertDeadline(const std::chrono::microseconds deadline,
+                        const IOOptions& opts) const {
+      // Give a leeway of +- 10us as it can take some time for the Get/
+      // MultiGet call to reach here, in order to avoid false alarms
+      std::chrono::microseconds now =
+          std::chrono::microseconds(env_->NowMicros());
+      ASSERT_EQ(deadline - now, opts.timeout);
+    }
+    DeadlineFS& fs_;
+    std::unique_ptr<FSRandomAccessFile> file_;
+    SpecialEnv* env_;
+  };
+
+  class DeadlineFS : public FileSystemWrapper {
+   public:
+    DeadlineFS(SpecialEnv* env)
+        : FileSystemWrapper(FileSystem::Default()),
+          delay_idx_(0),
+          deadline_(std::chrono::microseconds::zero()),
+          env_(env) {}
+    ~DeadlineFS() = default;
+
+    IOStatus NewRandomAccessFile(const std::string& fname,
+                                 const FileOptions& opts,
+                                 std::unique_ptr<FSRandomAccessFile>* result,
+                                 IODebugContext* dbg) override {
+      std::unique_ptr<FSRandomAccessFile> file;
+      IOStatus s;
+
+      s = target()->NewRandomAccessFile(fname, opts, &file, dbg);
+      result->reset(new DeadlineRandomAccessFile(*this, env_, file));
+      return s;
+    }
+
+    // Set a vector of {IO counter, delay in microseconds} pairs that control
+    // when to inject a delay and duration of the delay
+    void SetDelaySequence(const std::chrono::microseconds deadline,
+                          const std::vector<std::pair<int, int>>&& seq) {
+      int total_delay = 0;
+      for (auto& seq_iter : seq) {
+        // Ensure no individual delay is > 500ms
+        ASSERT_LT(seq_iter.second, 500000);
+        total_delay += seq_iter.second;
+      }
+      // ASSERT total delay is < 1s. This is mainly to keep the test from
+      // timing out in CI test frameworks
+      ASSERT_LT(total_delay, 1000000);
+      delay_seq_ = seq;
+      delay_idx_ = 0;
+      io_count_ = 0;
+      deadline_ = deadline;
+    }
+
+    // Increment the IO counter and return a delay in microseconds
+    bool ShouldDelay(int* delay) {
+      if (delay_idx_ < delay_seq_.size() &&
+          delay_seq_[delay_idx_].first == io_count_++) {
+        *delay = delay_seq_[delay_idx_].second;
+        delay_idx_++;
+        return true;
+      }
+      return false;
+    }
+
+    const std::chrono::microseconds GetDeadline() { return deadline_; }
+
+   private:
+    std::vector<std::pair<int, int>> delay_seq_;
+    size_t delay_idx_;
+    int io_count_;
+    std::chrono::microseconds deadline_;
+    SpecialEnv* env_;
+  };
+
+  inline void CheckStatus(std::vector<Status>& statuses, size_t num_ok) {
+    for (size_t i = 0; i < statuses.size(); ++i) {
+      if (i < num_ok) {
+        EXPECT_OK(statuses[i]);
+      } else {
+        EXPECT_EQ(statuses[i], Status::TimedOut());
+      }
+    }
+  }
+};
+
+TEST_F(DBBasicTestMultiGetDeadline, MultiGetDeadlineExceeded) {
+  std::shared_ptr<DBBasicTestMultiGetDeadline::DeadlineFS> fs(
+      new DBBasicTestMultiGetDeadline::DeadlineFS(env_));
+  std::unique_ptr<Env> env(new CompositeEnvWrapper(env_, fs));
+  Options options = CurrentOptions();
+  env_->SetTimeElapseOnlySleep(&options);
+
+  std::shared_ptr<Cache> cache = NewLRUCache(1048576);
+  BlockBasedTableOptions table_options;
+  table_options.block_cache = cache;
+  options.table_factory.reset(new BlockBasedTableFactory(table_options));
+  options.env = env.get();
+  ReopenWithColumnFamilies(GetCFNames(), options);
+
+  // Test the non-batched version of MultiGet with multiple column
+  // families
+  std::vector<std::string> key_str;
+  size_t i;
+  for (i = 0; i < 5; ++i) {
+    key_str.emplace_back(Key(static_cast<int>(i)));
+  }
+  std::vector<ColumnFamilyHandle*> cfs(key_str.size());
+  ;
+  std::vector<Slice> keys(key_str.size());
+  std::vector<std::string> values(key_str.size());
+  for (i = 0; i < key_str.size(); ++i) {
+    cfs[i] = handles_[i];
+    keys[i] = Slice(key_str[i].data(), key_str[i].size());
+  }
+
+  ReadOptions ro;
+  ro.deadline = std::chrono::microseconds{env->NowMicros() + 10000};
+  // Delay the first IO by 200ms
+  fs->SetDelaySequence(ro.deadline, {{0, 20000}});
+
+  std::vector<Status> statuses = dbfull()->MultiGet(ro, cfs, keys, &values);
+  // The first key is successful because we check after the lookup, but
+  // subsequent keys fail due to deadline exceeded
+  CheckStatus(statuses, 1);
+
+  // Clear the cache
+  cache->SetCapacity(0);
+  cache->SetCapacity(1048576);
+  // Test non-batched Multiget with multiple column families and
+  // introducing an IO delay in one of the middle CFs
+  key_str.clear();
+  for (i = 0; i < 10; ++i) {
+    key_str.emplace_back(Key(static_cast<int>(i)));
+  }
+  cfs.resize(key_str.size());
+  keys.resize(key_str.size());
+  values.resize(key_str.size());
+  for (i = 0; i < key_str.size(); ++i) {
+    // 2 keys per CF
+    cfs[i] = handles_[i / 2];
+    keys[i] = Slice(key_str[i].data(), key_str[i].size());
+  }
+  ro.deadline = std::chrono::microseconds{env->NowMicros() + 10000};
+  fs->SetDelaySequence(ro.deadline, {{1, 20000}});
+  statuses = dbfull()->MultiGet(ro, cfs, keys, &values);
+  CheckStatus(statuses, 3);
+
+  // Test batched MultiGet with an IO delay in the first data block read.
+  // Both keys in the first CF should succeed as they're in the same data
+  // block and would form one batch, and we check for deadline between
+  // batches.
+  std::vector<PinnableSlice> pin_values(keys.size());
+  cache->SetCapacity(0);
+  cache->SetCapacity(1048576);
+  statuses.clear();
+  statuses.resize(keys.size());
+  ro.deadline = std::chrono::microseconds{env->NowMicros() + 10000};
+  fs->SetDelaySequence(ro.deadline, {{0, 20000}});
+  dbfull()->MultiGet(ro, keys.size(), cfs.data(), keys.data(),
+                     pin_values.data(), statuses.data());
+  CheckStatus(statuses, 2);
+
+  // Similar to the previous one, but an IO delay in the third CF data block
+  // read
+  for (PinnableSlice& value : pin_values) {
+    value.Reset();
+  }
+  cache->SetCapacity(0);
+  cache->SetCapacity(1048576);
+  statuses.clear();
+  statuses.resize(keys.size());
+  ro.deadline = std::chrono::microseconds{env->NowMicros() + 10000};
+  fs->SetDelaySequence(ro.deadline, {{2, 20000}});
+  dbfull()->MultiGet(ro, keys.size(), cfs.data(), keys.data(),
+                     pin_values.data(), statuses.data());
+  CheckStatus(statuses, 6);
+
+  // Similar to the previous one, but an IO delay in the last but one CF
+  for (PinnableSlice& value : pin_values) {
+    value.Reset();
+  }
+  cache->SetCapacity(0);
+  cache->SetCapacity(1048576);
+  statuses.clear();
+  statuses.resize(keys.size());
+  ro.deadline = std::chrono::microseconds{env->NowMicros() + 10000};
+  fs->SetDelaySequence(ro.deadline, {{3, 20000}});
+  dbfull()->MultiGet(ro, keys.size(), cfs.data(), keys.data(),
+                     pin_values.data(), statuses.data());
+  CheckStatus(statuses, 8);
+
+  // Test batched MultiGet with single CF and lots of keys. Inject delay
+  // into the second batch of keys. As each batch is 32, the first 64 keys,
+  // i.e first two batches, should succeed and the rest should time out
+  for (PinnableSlice& value : pin_values) {
+    value.Reset();
+  }
+  cache->SetCapacity(0);
+  cache->SetCapacity(1048576);
+  key_str.clear();
+  for (i = 0; i < 100; ++i) {
+    key_str.emplace_back(Key(static_cast<int>(i)));
+  }
+  keys.resize(key_str.size());
+  pin_values.clear();
+  pin_values.resize(key_str.size());
+  for (i = 0; i < key_str.size(); ++i) {
+    keys[i] = Slice(key_str[i].data(), key_str[i].size());
+  }
+  statuses.clear();
+  statuses.resize(keys.size());
+  ro.deadline = std::chrono::microseconds{env->NowMicros() + 10000};
+  fs->SetDelaySequence(ro.deadline, {{1, 20000}});
+  dbfull()->MultiGet(ro, handles_[0], keys.size(), keys.data(),
+                     pin_values.data(), statuses.data());
+  CheckStatus(statuses, 64);
+  Close();
+}

 }  // namespace ROCKSDB_NAMESPACE

@@ -517,6 +517,139 @@ TEST_F(DBBlockCacheTest, IndexAndFilterBlocksCachePriority) {
  }
 }

+namespace {
+
+// An LRUCache wrapper that can falsely report "not found" on Lookup.
+// This allows us to manipulate BlockBasedTableReader into thinking
+// another thread inserted the data in between Lookup and Insert,
+// while mostly preserving the LRUCache interface/behavior.
+class LookupLiarCache : public CacheWrapper {
+  int nth_lookup_not_found_ = 0;
+
+ public:
+  explicit LookupLiarCache(std::shared_ptr<Cache> target)
+      : CacheWrapper(std::move(target)) {}
+
+  Handle* Lookup(const Slice& key, Statistics* stats) override {
+    if (nth_lookup_not_found_ == 1) {
+      nth_lookup_not_found_ = 0;
+      return nullptr;
+    }
+    if (nth_lookup_not_found_ > 1) {
+      --nth_lookup_not_found_;
+    }
+    return CacheWrapper::Lookup(key, stats);
+  }
+
+  // 1 == next lookup, 2 == after next, etc.
+  void SetNthLookupNotFound(int n) { nth_lookup_not_found_ = n; }
+};
+
+}  // anonymous namespace
+
+TEST_F(DBBlockCacheTest, AddRedundantStats) {
+  const size_t capacity = size_t{1} << 25;
+  const int num_shard_bits = 0;  // 1 shard
+  int iterations_tested = 0;
+  for (std::shared_ptr<Cache> base_cache :
+       {NewLRUCache(capacity, num_shard_bits),
+        NewClockCache(capacity, num_shard_bits)}) {
+    if (!base_cache) {
+      // Skip clock cache when not supported
+      continue;
+    }
+    ++iterations_tested;
+    Options options = CurrentOptions();
+    options.create_if_missing = true;
+    options.statistics = ROCKSDB_NAMESPACE::CreateDBStatistics();
+
+    std::shared_ptr<LookupLiarCache> cache =
+        std::make_shared<LookupLiarCache>(base_cache);
+
+    BlockBasedTableOptions table_options;
+    table_options.cache_index_and_filter_blocks = true;
+    table_options.block_cache = cache;
+    table_options.filter_policy.reset(NewBloomFilterPolicy(50));
+    options.table_factory.reset(new BlockBasedTableFactory(table_options));
+    DestroyAndReopen(options);
+
+    // Create a new table.
+    ASSERT_OK(Put("foo", "value"));
+    ASSERT_OK(Put("bar", "value"));
+    ASSERT_OK(Flush());
+    ASSERT_EQ(1, NumTableFilesAtLevel(0));
+
+    // Normal access filter+index+data.
+    ASSERT_EQ("value", Get("foo"));
+
+    ASSERT_EQ(1, TestGetTickerCount(options, BLOCK_CACHE_INDEX_ADD));
+    ASSERT_EQ(1, TestGetTickerCount(options, BLOCK_CACHE_FILTER_ADD));
+    ASSERT_EQ(1, TestGetTickerCount(options, BLOCK_CACHE_DATA_ADD));
+    // --------
+    ASSERT_EQ(3, TestGetTickerCount(options, BLOCK_CACHE_ADD));
+
+    ASSERT_EQ(0, TestGetTickerCount(options, BLOCK_CACHE_INDEX_ADD_REDUNDANT));
+    ASSERT_EQ(0, TestGetTickerCount(options, BLOCK_CACHE_FILTER_ADD_REDUNDANT));
+    ASSERT_EQ(0, TestGetTickerCount(options, BLOCK_CACHE_DATA_ADD_REDUNDANT));
+    // --------
+    ASSERT_EQ(0, TestGetTickerCount(options, BLOCK_CACHE_ADD_REDUNDANT));
+
+    // Againt access filter+index+data, but force redundant load+insert on index
+    cache->SetNthLookupNotFound(2);
+    ASSERT_EQ("value", Get("bar"));
+
+    ASSERT_EQ(2, TestGetTickerCount(options, BLOCK_CACHE_INDEX_ADD));
+    ASSERT_EQ(1, TestGetTickerCount(options, BLOCK_CACHE_FILTER_ADD));
+    ASSERT_EQ(1, TestGetTickerCount(options, BLOCK_CACHE_DATA_ADD));
+    // --------
+    ASSERT_EQ(4, TestGetTickerCount(options, BLOCK_CACHE_ADD));
+
+    ASSERT_EQ(1, TestGetTickerCount(options, BLOCK_CACHE_INDEX_ADD_REDUNDANT));
+    ASSERT_EQ(0, TestGetTickerCount(options, BLOCK_CACHE_FILTER_ADD_REDUNDANT));
+    ASSERT_EQ(0, TestGetTickerCount(options, BLOCK_CACHE_DATA_ADD_REDUNDANT));
+    // --------
+    ASSERT_EQ(1, TestGetTickerCount(options, BLOCK_CACHE_ADD_REDUNDANT));
+
+    // Access just filter (with high probability), and force redundant
+    // load+insert
+    cache->SetNthLookupNotFound(1);
+    ASSERT_EQ("NOT_FOUND", Get("this key was not added"));
+
+    EXPECT_EQ(2, TestGetTickerCount(options, BLOCK_CACHE_INDEX_ADD));
+    EXPECT_EQ(2, TestGetTickerCount(options, BLOCK_CACHE_FILTER_ADD));
+    EXPECT_EQ(1, TestGetTickerCount(options, BLOCK_CACHE_DATA_ADD));
+    // --------
+    EXPECT_EQ(5, TestGetTickerCount(options, BLOCK_CACHE_ADD));
+
+    EXPECT_EQ(1, TestGetTickerCount(options, BLOCK_CACHE_INDEX_ADD_REDUNDANT));
+    EXPECT_EQ(1, TestGetTickerCount(options, BLOCK_CACHE_FILTER_ADD_REDUNDANT));
+    EXPECT_EQ(0, TestGetTickerCount(options, BLOCK_CACHE_DATA_ADD_REDUNDANT));
+    // --------
+    EXPECT_EQ(2, TestGetTickerCount(options, BLOCK_CACHE_ADD_REDUNDANT));
+
+    // Access just data, forcing redundant load+insert
+    ReadOptions read_options;
+    std::unique_ptr<Iterator> iter{db_->NewIterator(read_options)};
+    cache->SetNthLookupNotFound(1);
+    iter->SeekToFirst();
+    ASSERT_TRUE(iter->Valid());
+    ASSERT_EQ(iter->key(), "bar");
+
+    EXPECT_EQ(2, TestGetTickerCount(options, BLOCK_CACHE_INDEX_ADD));
+    EXPECT_EQ(2, TestGetTickerCount(options, BLOCK_CACHE_FILTER_ADD));
+    EXPECT_EQ(2, TestGetTickerCount(options, BLOCK_CACHE_DATA_ADD));
+    // --------
+    EXPECT_EQ(6, TestGetTickerCount(options, BLOCK_CACHE_ADD));
+
+    EXPECT_EQ(1, TestGetTickerCount(options, BLOCK_CACHE_INDEX_ADD_REDUNDANT));
+    EXPECT_EQ(1, TestGetTickerCount(options, BLOCK_CACHE_FILTER_ADD_REDUNDANT));
+    EXPECT_EQ(1, TestGetTickerCount(options, BLOCK_CACHE_DATA_ADD_REDUNDANT));
+    // --------
+    EXPECT_EQ(3, TestGetTickerCount(options, BLOCK_CACHE_ADD_REDUNDANT));
+  }
+  EXPECT_GE(iterations_tested, 1);
+}
+
 TEST_F(DBBlockCacheTest, ParanoidFileChecks) {
  Options options = CurrentOptions();
  options.create_if_missing = true;
@@ -8,6 +8,7 @@
 // found in the LICENSE file. See the AUTHORS file for names of contributors.

 #include "db/db_test_util.h"
+#include "options/options_helper.h"
 #include "port/stack_trace.h"
 #include "rocksdb/perf_context.h"
 #include "table/block_based/filter_policy_internal.h"
@@ -1029,6 +1030,206 @@ TEST_F(DBBloomFilterTest, MemtablePrefixBloomOutOfDomain) {
  ASSERT_EQ(kKey, iter->key());
 }

+class DBBloomFilterTestVaryPrefixAndFormatVer
+    : public DBTestBase,
+      public testing::WithParamInterface<std::tuple<bool, uint32_t>> {
+ protected:
+  bool use_prefix_;
+  uint32_t format_version_;
+
+ public:
+  DBBloomFilterTestVaryPrefixAndFormatVer()
+      : DBTestBase("/db_bloom_filter_tests") {}
+
+  ~DBBloomFilterTestVaryPrefixAndFormatVer() override {}
+
+  void SetUp() override {
+    use_prefix_ = std::get<0>(GetParam());
+    format_version_ = std::get<1>(GetParam());
+  }
+
+  static std::string UKey(uint32_t i) { return Key(static_cast<int>(i)); }
+};
+
+TEST_P(DBBloomFilterTestVaryPrefixAndFormatVer, PartitionedMultiGet) {
+  Options options = CurrentOptions();
+  if (use_prefix_) {
+    // Entire key from UKey()
+    options.prefix_extractor.reset(NewCappedPrefixTransform(9));
+  }
+  options.statistics = ROCKSDB_NAMESPACE::CreateDBStatistics();
+  BlockBasedTableOptions bbto;
+  bbto.filter_policy.reset(NewBloomFilterPolicy(20));
+  bbto.partition_filters = true;
+  bbto.index_type = BlockBasedTableOptions::IndexType::kTwoLevelIndexSearch;
+  bbto.whole_key_filtering = !use_prefix_;
+  bbto.metadata_block_size = 128;
+  options.table_factory.reset(NewBlockBasedTableFactory(bbto));
+  DestroyAndReopen(options);
+  ReadOptions ropts;
+
+  constexpr uint32_t N = 10000;
+  // Add N/2 evens
+  for (uint32_t i = 0; i < N; i += 2) {
+    ASSERT_OK(Put(UKey(i), UKey(i)));
+  }
+  ASSERT_OK(Flush());
+#ifndef ROCKSDB_LITE
+  ASSERT_EQ(TotalTableFiles(), 1);
+#endif
+
+  constexpr uint32_t Q = 29;
+  // MultiGet In
+  std::array<std::string, Q> keys;
+  std::array<Slice, Q> key_slices;
+  std::array<ColumnFamilyHandle*, Q> column_families;
+  // MultiGet Out
+  std::array<Status, Q> statuses;
+  std::array<PinnableSlice, Q> values;
+
+  TestGetAndResetTickerCount(options, BLOCK_CACHE_FILTER_HIT);
+  TestGetAndResetTickerCount(options, BLOCK_CACHE_FILTER_MISS);
+  TestGetAndResetTickerCount(options, BLOOM_FILTER_PREFIX_USEFUL);
+  TestGetAndResetTickerCount(options, BLOOM_FILTER_USEFUL);
+  TestGetAndResetTickerCount(options, BLOOM_FILTER_PREFIX_CHECKED);
+  TestGetAndResetTickerCount(options, BLOOM_FILTER_FULL_POSITIVE);
+  TestGetAndResetTickerCount(options, BLOOM_FILTER_FULL_TRUE_POSITIVE);
+
+  // Check that initial clump of keys only loads one partition filter from
+  // block cache.
+  // And that spread out keys load many partition filters.
+  // In both cases, mix present vs. not present keys.
+  for (uint32_t stride : {uint32_t{1}, (N / Q) | 1}) {
+    for (uint32_t i = 0; i < Q; ++i) {
+      keys[i] = UKey(i * stride);
+      key_slices[i] = Slice(keys[i]);
+      column_families[i] = db_->DefaultColumnFamily();
+      statuses[i] = Status();
+      values[i] = PinnableSlice();
+    }
+
+    db_->MultiGet(ropts, Q, &column_families[0], &key_slices[0], &values[0],
+                  /*timestamps=*/nullptr, &statuses[0], true);
+
+    // Confirm correct status results
+    uint32_t number_not_found = 0;
+    for (uint32_t i = 0; i < Q; ++i) {
+      if ((i * stride % 2) == 0) {
+        ASSERT_OK(statuses[i]);
+      } else {
+        ASSERT_TRUE(statuses[i].IsNotFound());
+        ++number_not_found;
+      }
+    }
+
+    // Confirm correct Bloom stats (no FPs)
+    uint64_t filter_useful = TestGetAndResetTickerCount(
+        options,
+        use_prefix_ ? BLOOM_FILTER_PREFIX_USEFUL : BLOOM_FILTER_USEFUL);
+    uint64_t filter_checked =
+        TestGetAndResetTickerCount(options, use_prefix_
+                                                ? BLOOM_FILTER_PREFIX_CHECKED
+                                                : BLOOM_FILTER_FULL_POSITIVE) +
+        (use_prefix_ ? 0 : filter_useful);
+    EXPECT_EQ(filter_useful, number_not_found);
+    EXPECT_EQ(filter_checked, Q);
+    if (!use_prefix_) {
+      EXPECT_EQ(
+          TestGetAndResetTickerCount(options, BLOOM_FILTER_FULL_TRUE_POSITIVE),
+          Q - number_not_found);
+    }
+
+    // Confirm no duplicate loading same filter partition
+    uint64_t filter_accesses =
+        TestGetAndResetTickerCount(options, BLOCK_CACHE_FILTER_HIT) +
+        TestGetAndResetTickerCount(options, BLOCK_CACHE_FILTER_MISS);
+    if (stride == 1) {
+      EXPECT_EQ(filter_accesses, 1);
+    } else {
+      // for large stride
+      EXPECT_GE(filter_accesses, Q / 2 + 1);
+    }
+  }
+
+  // Check that a clump of keys (present and not) works when spanning
+  // two partitions
+  int found_spanning = 0;
+  for (uint32_t start = 0; start < N / 2;) {
+    for (uint32_t i = 0; i < Q; ++i) {
+      keys[i] = UKey(start + i);
+      key_slices[i] = Slice(keys[i]);
+      column_families[i] = db_->DefaultColumnFamily();
+      statuses[i] = Status();
+      values[i] = PinnableSlice();
+    }
+
+    db_->MultiGet(ropts, Q, &column_families[0], &key_slices[0], &values[0],
+                  /*timestamps=*/nullptr, &statuses[0], true);
+
+    // Confirm correct status results
+    uint32_t number_not_found = 0;
+    for (uint32_t i = 0; i < Q; ++i) {
+      if (((start + i) % 2) == 0) {
+        ASSERT_OK(statuses[i]);
+      } else {
+        ASSERT_TRUE(statuses[i].IsNotFound());
+        ++number_not_found;
+      }
+    }
+
+    // Confirm correct Bloom stats (might see some FPs)
+    uint64_t filter_useful = TestGetAndResetTickerCount(
+        options,
+        use_prefix_ ? BLOOM_FILTER_PREFIX_USEFUL : BLOOM_FILTER_USEFUL);
+    uint64_t filter_checked =
+        TestGetAndResetTickerCount(options, use_prefix_
+                                                ? BLOOM_FILTER_PREFIX_CHECKED
+                                                : BLOOM_FILTER_FULL_POSITIVE) +
+        (use_prefix_ ? 0 : filter_useful);
+    EXPECT_GE(filter_useful, number_not_found - 2);  // possible FP
+    EXPECT_EQ(filter_checked, Q);
+    if (!use_prefix_) {
+      EXPECT_EQ(
+          TestGetAndResetTickerCount(options, BLOOM_FILTER_FULL_TRUE_POSITIVE),
+          Q - number_not_found);
+    }
+
+    // Confirm no duplicate loading of same filter partition
+    uint64_t filter_accesses =
+        TestGetAndResetTickerCount(options, BLOCK_CACHE_FILTER_HIT) +
+        TestGetAndResetTickerCount(options, BLOCK_CACHE_FILTER_MISS);
+    if (filter_accesses == 2) {
+      // Spanned across partitions.
+      ++found_spanning;
+      if (found_spanning >= 2) {
+        break;
+      } else {
+        // Ensure that at least once we have at least one present and
+        // one non-present key on both sides of partition boundary.
+        start += 2;
+      }
+    } else {
+      EXPECT_EQ(filter_accesses, 1);
+      // See explanation at "start += 2"
+      start += Q - 4;
+    }
+  }
+  EXPECT_TRUE(found_spanning >= 2);
+}
+
+INSTANTIATE_TEST_CASE_P(DBBloomFilterTestVaryPrefixAndFormatVer,
+                        DBBloomFilterTestVaryPrefixAndFormatVer,
+                        ::testing::Values(
+                            // (use_prefix, format_version)
+                            std::make_tuple(false, 2),
+                            std::make_tuple(false, 3),
+                            std::make_tuple(false, 4),
+                            std::make_tuple(false, 5),
+                            std::make_tuple(true, 2),
+                            std::make_tuple(true, 3),
+                            std::make_tuple(true, 4),
+                            std::make_tuple(true, 5)));
+
 #ifndef ROCKSDB_LITE
 namespace {
 namespace BFP2 {
@@ -1343,8 +1544,7 @@ TEST_F(DBBloomFilterTest, OptimizeFiltersForHits) {
  for (int i = 0; i < numkeys; i += 2) {
    keys.push_back(i);
  }
-  std::random_shuffle(std::begin(keys), std::end(keys));
-
+  RandomShuffle(std::begin(keys), std::end(keys));
  int num_inserted = 0;
  for (int key : keys) {
    ASSERT_OK(Put(1, Key(key), "val"));
@@ -157,21 +157,21 @@ Options DeletionTriggerOptions(Options options) {
 bool HaveOverlappingKeyRanges(
    const Comparator* c,
    const SstFileMetaData& a, const SstFileMetaData& b) {
-  if (c->Compare(a.smallestkey, b.smallestkey) >= 0) {
-    if (c->Compare(a.smallestkey, b.largestkey) <= 0) {
+  if (c->CompareWithoutTimestamp(a.smallestkey, b.smallestkey) >= 0) {
+    if (c->CompareWithoutTimestamp(a.smallestkey, b.largestkey) <= 0) {
      // b.smallestkey <= a.smallestkey <= b.largestkey
      return true;
    }
-  } else if (c->Compare(a.largestkey, b.smallestkey) >= 0) {
+  } else if (c->CompareWithoutTimestamp(a.largestkey, b.smallestkey) >= 0) {
    // a.smallestkey < b.smallestkey <= a.largestkey
    return true;
  }
-  if (c->Compare(a.largestkey, b.largestkey) <= 0) {
-    if (c->Compare(a.largestkey, b.smallestkey) >= 0) {
+  if (c->CompareWithoutTimestamp(a.largestkey, b.largestkey) <= 0) {
+    if (c->CompareWithoutTimestamp(a.largestkey, b.smallestkey) >= 0) {
      // b.smallestkey <= a.largestkey <= b.largestkey
      return true;
    }
-  } else if (c->Compare(a.smallestkey, b.largestkey) <= 0) {
+  } else if (c->CompareWithoutTimestamp(a.smallestkey, b.largestkey) <= 0) {
    // a.smallestkey <= b.largestkey < a.largestkey
    return true;
  }
@@ -4762,7 +4762,7 @@ TEST_P(CompactionPriTest, Test) {
  for (int i = 0; i < kNKeys; i++) {
    keys[i] = i;
  }
-  std::random_shuffle(std::begin(keys), std::end(keys));
+  RandomShuffle(std::begin(keys), std::end(keys), rnd.Next());

  for (int i = 0; i < kNKeys; i++) {
    ASSERT_OK(Put(Key(keys[i]), RandomString(&rnd, 102)));
@@ -5024,10 +5024,11 @@ TEST_P(DBCompactionTestWithParam, FixFileIngestionCompactionDeadlock) {

 TEST_F(DBCompactionTest, ConsistencyFailTest) {
  Options options = CurrentOptions();
+  options.force_consistency_checks = true;
  DestroyAndReopen(options);

  ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->SetCallBack(
-      "VersionBuilder::CheckConsistency", [&](void* arg) {
+      "VersionBuilder::CheckConsistency0", [&](void* arg) {
        auto p =
            reinterpret_cast<std::pair<FileMetaData**, FileMetaData**>*>(arg);
        // just swap the two FileMetaData so that we hit error
@@ -5046,6 +5047,48 @@ TEST_F(DBCompactionTest, ConsistencyFailTest) {

  ASSERT_NOK(Put("foo", "bar"));
  ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->DisableProcessing();
+  SyncPoint::GetInstance()->ClearAllCallBacks();
+}
+
+TEST_F(DBCompactionTest, ConsistencyFailTest2) {
+  Options options = CurrentOptions();
+  options.force_consistency_checks = true;
+  options.target_file_size_base = 1000;
+  options.level0_file_num_compaction_trigger = 2;
+  BlockBasedTableOptions bbto;
+  bbto.block_size = 400;  // small block size
+  options.table_factory.reset(new BlockBasedTableFactory(bbto));
+  DestroyAndReopen(options);
+
+  ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->SetCallBack(
+      "VersionBuilder::CheckConsistency1", [&](void* arg) {
+        auto p =
+            reinterpret_cast<std::pair<FileMetaData**, FileMetaData**>*>(arg);
+        // just swap the two FileMetaData so that we hit error
+        // in CheckConsistency funcion
+        FileMetaData* temp = *(p->first);
+        *(p->first) = *(p->second);
+        *(p->second) = temp;
+      });
+
+  ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->EnableProcessing();
+
+  Random rnd(301);
+  std::string value = RandomString(&rnd, 1000);
+
+  ASSERT_OK(Put("foo1", value));
+  ASSERT_OK(Put("z", ""));
+  Flush();
+  ASSERT_OK(Put("foo2", value));
+  ASSERT_OK(Put("z", ""));
+  Flush();
+
+  // This probably returns non-OK, but we rely on the next Put()
+  // to determine the DB is frozen.
+  dbfull()->TEST_WaitForCompact();
+  ASSERT_NOK(Put("foo", "bar"));
+  ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->DisableProcessing();
+  SyncPoint::GetInstance()->ClearAllCallBacks();
 }

 void IngestOneKeyValue(DBImpl* db, const std::string& key,
@@ -50,7 +50,7 @@ TEST_F(DBTestDynamicLevel, DynamicLevelMaxBytesBase) {
      keys[i] = i;
    }
    if (ordered_insert == 0) {
-      std::random_shuffle(std::begin(keys), std::end(keys));
+      RandomShuffle(std::begin(keys), std::end(keys), rnd.Next());
    }
    for (int max_background_compactions = 1; max_background_compactions < 4;
         max_background_compactions += 2) {
@@ -90,6 +90,9 @@ Status DBImpl::GetLiveFiles(std::vector<std::string>& ret,
      mutex_.Unlock();
      status = AtomicFlushMemTables(cfds, FlushOptions(),
                                    FlushReason::kGetLiveFiles);
+      if (status.IsColumnFamilyDropped()) {
+        status = Status::OK();
+      }
      mutex_.Lock();
    } else {
      for (auto cfd : *versions_->GetColumnFamilySet()) {
@@ -103,8 +106,10 @@ Status DBImpl::GetLiveFiles(std::vector<std::string>& ret,
        TEST_SYNC_POINT("DBImpl::GetLiveFiles:2");
        mutex_.Lock();
        cfd->UnrefAndTryDelete();
-        if (!status.ok()) {
+        if (!status.ok() && !status.IsColumnFamilyDropped()) {
          break;
+        } else if (status.IsColumnFamilyDropped()) {
+          status = Status::OK();
        }
      }
    }
@@ -118,27 +123,33 @@ Status DBImpl::GetLiveFiles(std::vector<std::string>& ret,
    }
  }

-  // Make a set of all of the live *.sst files
-  std::vector<FileDescriptor> live;
+  // Make a set of all of the live table and blob files
+  std::vector<uint64_t> live_table_files;
+  std::vector<uint64_t> live_blob_files;
  for (auto cfd : *versions_->GetColumnFamilySet()) {
    if (cfd->IsDropped()) {
      continue;
    }
-    cfd->current()->AddLiveFiles(&live);
+    cfd->current()->AddLiveFiles(&live_table_files, &live_blob_files);
  }

  ret.clear();
-  ret.reserve(live.size() + 3);  // *.sst + CURRENT + MANIFEST + OPTIONS
+  ret.reserve(live_table_files.size() + live_blob_files.size() +
+              3);  // for CURRENT + MANIFEST + OPTIONS

  // create names of the live files. The names are not absolute
  // paths, instead they are relative to dbname_;
-  for (const auto& live_file : live) {
-    ret.push_back(MakeTableFileName("", live_file.GetNumber()));
+  for (const auto& table_file_number : live_table_files) {
+    ret.emplace_back(MakeTableFileName("", table_file_number));
  }

-  ret.push_back(CurrentFileName(""));
-  ret.push_back(DescriptorFileName("", versions_->manifest_file_number()));
-  ret.push_back(OptionsFileName("", versions_->options_file_number()));
+  for (const auto& blob_file_number : live_blob_files) {
+    ret.emplace_back(BlobFileName("", blob_file_number));
+  }
+
+  ret.emplace_back(CurrentFileName(""));
+  ret.emplace_back(DescriptorFileName("", versions_->manifest_file_number()));
+  ret.emplace_back(OptionsFileName("", versions_->options_file_number()));

  // find length of manifest file while holding the mutex lock
  *manifest_file_size = versions_->manifest_file_size();
@@ -870,9 +870,7 @@ void DBImpl::DumpStats() {
 Status DBImpl::TablesRangeTombstoneSummary(ColumnFamilyHandle* column_family,
                                           int max_entries_to_print,
                                           std::string* out_str) {
-  auto* cfh =
-      static_cast_with_check<ColumnFamilyHandleImpl, ColumnFamilyHandle>(
-          column_family);
+  auto* cfh = static_cast_with_check<ColumnFamilyHandleImpl>(column_family);
  ColumnFamilyData* cfd = cfh->cfd();

  SuperVersion* super_version = cfd->GetReferencedSuperVersion(this);
@@ -1010,12 +1008,12 @@ Status DBImpl::SetDBOptions(
    }
    if (s.ok()) {
      const BGJobLimits current_bg_job_limits =
-          GetBGJobLimits(immutable_db_options_.max_background_flushes,
+          GetBGJobLimits(mutable_db_options_.max_background_flushes,
                         mutable_db_options_.max_background_compactions,
                         mutable_db_options_.max_background_jobs,
                         /* parallelize_compactions */ true);
      const BGJobLimits new_bg_job_limits = GetBGJobLimits(
-          immutable_db_options_.max_background_flushes,
+          new_options.max_background_flushes,
          new_options.max_background_compactions,
          new_options.max_background_jobs, /* parallelize_compactions */ true);

@@ -1313,7 +1311,7 @@ bool DBImpl::SetPreserveDeletesSequenceNumber(SequenceNumber seqnum) {

 InternalIterator* DBImpl::NewInternalIterator(
    Arena* arena, RangeDelAggregator* range_del_agg, SequenceNumber sequence,
-    ColumnFamilyHandle* column_family) {
+    ColumnFamilyHandle* column_family, bool allow_unprepared_value) {
  ColumnFamilyData* cfd;
  if (column_family == nullptr) {
    cfd = default_cf_handle_->cfd();
@@ -1327,7 +1325,7 @@ InternalIterator* DBImpl::NewInternalIterator(
  mutex_.Unlock();
  ReadOptions roptions;
  return NewInternalIterator(roptions, cfd, super_version, arena, range_del_agg,
-                             sequence);
+                             sequence, allow_unprepared_value);
 }

 void DBImpl::SchedulePurge() {
@@ -1450,7 +1448,8 @@ InternalIterator* DBImpl::NewInternalIterator(const ReadOptions& read_options,
                                              SuperVersion* super_version,
                                              Arena* arena,
                                              RangeDelAggregator* range_del_agg,
-                                              SequenceNumber sequence) {
+                                              SequenceNumber sequence,
+                                              bool allow_unprepared_value) {
  InternalIterator* internal_iter;
  assert(arena != nullptr);
  assert(range_del_agg != nullptr);
@@ -1482,7 +1481,8 @@ InternalIterator* DBImpl::NewInternalIterator(const ReadOptions& read_options,
    // Collect iterators for files in L0 - Ln
    if (read_options.read_tier != kMemtableTier) {
      super_version->current->AddIterators(read_options, file_options_,
-                                           &merge_iter_builder, range_del_agg);
+                                           &merge_iter_builder, range_del_agg,
+                                           allow_unprepared_value);
    }
    internal_iter = merge_iter_builder.Finish();
    IterState* cleanup =
@@ -1527,6 +1527,20 @@ Status DBImpl::GetImpl(const ReadOptions& read_options, const Slice& key,
                       GetImplOptions& get_impl_options) {
  assert(get_impl_options.value != nullptr ||
         get_impl_options.merge_operands != nullptr);
+
+#ifndef NDEBUG
+  assert(get_impl_options.column_family);
+  ColumnFamilyHandle* cf = get_impl_options.column_family;
+  const Comparator* const ucmp = cf->GetComparator();
+  assert(ucmp);
+  if (ucmp->timestamp_size() > 0) {
+    assert(read_options.timestamp);
+    assert(read_options.timestamp->size() == ucmp->timestamp_size());
+  } else {
+    assert(!read_options.timestamp);
+  }
+#endif  // NDEBUG
+
  PERF_CPU_TIMER_GUARD(get_cpu_nanos, env_);
  StopWatch sw(env_, stats_, DB_GET);
  PERF_TIMER_GUARD(get_snapshot_time);
@@ -1702,7 +1716,7 @@ std::vector<Status> DBImpl::MultiGet(
    const std::vector<ColumnFamilyHandle*>& column_family,
    const std::vector<Slice>& keys, std::vector<std::string>* values) {
  return MultiGet(read_options, column_family, keys, values,
-                  /*timestamps*/ nullptr);
+                  /*timestamps=*/nullptr);
 }

 std::vector<Status> DBImpl::MultiGet(
@@ -1714,6 +1728,20 @@ std::vector<Status> DBImpl::MultiGet(
  StopWatch sw(env_, stats_, DB_MULTIGET);
  PERF_TIMER_GUARD(get_snapshot_time);

+#ifndef NDEBUG
+  for (const auto* cfh : column_family) {
+    assert(cfh);
+    const Comparator* const ucmp = cfh->GetComparator();
+    assert(ucmp);
+    if (ucmp->timestamp_size() > 0) {
+      assert(read_options.timestamp);
+      assert(ucmp->timestamp_size() == read_options.timestamp->size());
+    } else {
+      assert(!read_options.timestamp);
+    }
+  }
+#endif  // NDEBUG
+
  SequenceNumber consistent_seqnum;

  std::unordered_map<uint32_t, MultiGetColumnFamilyData> multiget_cf_data(
@@ -1758,14 +1786,16 @@ std::vector<Status> DBImpl::MultiGet(
  // s is both in/out. When in, s could either be OK or MergeInProgress.
  // merge_operands will contain the sequence of merges in the latter case.
  size_t num_found = 0;
-  for (size_t i = 0; i < num_keys; ++i) {
+  size_t keys_read;
+  for (keys_read = 0; keys_read < num_keys; ++keys_read) {
    merge_context.Clear();
-    Status& s = stat_list[i];
-    std::string* value = &(*values)[i];
-    std::string* timestamp = timestamps ? &(*timestamps)[i] : nullptr;
+    Status& s = stat_list[keys_read];
+    std::string* value = &(*values)[keys_read];
+    std::string* timestamp = timestamps ? &(*timestamps)[keys_read] : nullptr;

-    LookupKey lkey(keys[i], consistent_seqnum, read_options.timestamp);
-    auto cfh = reinterpret_cast<ColumnFamilyHandleImpl*>(column_family[i]);
+    LookupKey lkey(keys[keys_read], consistent_seqnum, read_options.timestamp);
+    auto cfh =
+        static_cast_with_check<ColumnFamilyHandleImpl>(column_family[keys_read]);
    SequenceNumber max_covering_tombstone_seq = 0;
    auto mgd_iter = multiget_cf_data.find(cfh->cfd()->GetID());
    assert(mgd_iter != multiget_cf_data.end());
@@ -1801,6 +1831,22 @@ std::vector<Status> DBImpl::MultiGet(
      bytes_read += value->size();
      num_found++;
    }
+
+    if (read_options.deadline.count() &&
+        env_->NowMicros() >
+            static_cast<uint64_t>(read_options.deadline.count())) {
+      break;
+    }
+  }
+
+  if (keys_read < num_keys) {
+    // The only reason to break out of the loop is when the deadline is
+    // exceeded
+    assert(env_->NowMicros() >
+        static_cast<uint64_t>(read_options.deadline.count()));
+    for (++keys_read; keys_read < num_keys; ++keys_read) {
+      stat_list[keys_read] = Status::TimedOut();
+    }
  }

  // Post processing (decrement reference counts and record statistics)
@@ -1955,7 +2001,7 @@ void DBImpl::MultiGet(const ReadOptions& read_options, const size_t num_keys,
                      PinnableSlice* values, Status* statuses,
                      const bool sorted_input) {
  return MultiGet(read_options, num_keys, column_families, keys, values,
-                  /*timestamps*/ nullptr, statuses, sorted_input);
+                  /*timestamps=*/nullptr, statuses, sorted_input);
 }

 void DBImpl::MultiGet(const ReadOptions& read_options, const size_t num_keys,
@@ -1965,12 +2011,29 @@ void DBImpl::MultiGet(const ReadOptions& read_options, const size_t num_keys,
  if (num_keys == 0) {
    return;
  }
+
+#ifndef NDEBUG
+  for (size_t i = 0; i < num_keys; ++i) {
+    ColumnFamilyHandle* cfh = column_families[i];
+    assert(cfh);
+    const Comparator* const ucmp = cfh->GetComparator();
+    assert(ucmp);
+    if (ucmp->timestamp_size() > 0) {
+      assert(read_options.timestamp);
+      assert(read_options.timestamp->size() == ucmp->timestamp_size());
+    } else {
+      assert(!read_options.timestamp);
+    }
+  }
+#endif  // NDEBUG
+
  autovector<KeyContext, MultiGetContext::MAX_BATCH_SIZE> key_context;
  autovector<KeyContext*, MultiGetContext::MAX_BATCH_SIZE> sorted_keys;
  sorted_keys.resize(num_keys);
  for (size_t i = 0; i < num_keys; ++i) {
    key_context.emplace_back(column_families[i], keys[i], &values[i],
-                             &timestamps[i], &statuses[i]);
+                             timestamps ? &timestamps[i] : nullptr,
+                             &statuses[i]);
  }
  for (size_t i = 0; i < num_keys; ++i) {
    sorted_keys[i] = &key_context[i];
@@ -2010,14 +2073,31 @@ void DBImpl::MultiGet(const ReadOptions& read_options, const size_t num_keys,
      read_options, nullptr, iter_deref_lambda, &multiget_cf_data,
      &consistent_seqnum);

-  for (auto cf_iter = multiget_cf_data.begin();
-       cf_iter != multiget_cf_data.end(); ++cf_iter) {
-    MultiGetImpl(read_options, cf_iter->start, cf_iter->num_keys, &sorted_keys,
-                 cf_iter->super_version, consistent_seqnum, nullptr, nullptr);
+  Status s;
+  auto cf_iter = multiget_cf_data.begin();
+  for (; cf_iter != multiget_cf_data.end(); ++cf_iter) {
+    s = MultiGetImpl(read_options, cf_iter->start, cf_iter->num_keys,
+                     &sorted_keys, cf_iter->super_version, consistent_seqnum,
+                     nullptr, nullptr);
+    if (!s.ok()) {
+      break;
+    }
+  }
+  if (!s.ok()) {
+    assert(s.IsTimedOut());
+    for (++cf_iter; cf_iter != multiget_cf_data.end(); ++cf_iter) {
+      for (size_t i = cf_iter->start; i < cf_iter->start + cf_iter->num_keys;
+           ++i) {
+        *sorted_keys[i]->s = Status::TimedOut();
+      }
+    }
+  }
+
+  for (const auto& iter : multiget_cf_data) {
    if (!unref_only) {
-      ReturnAndCleanupSuperVersion(cf_iter->cfd, cf_iter->super_version);
+      ReturnAndCleanupSuperVersion(iter.cfd, iter.super_version);
    } else {
-      cf_iter->cfd->GetSuperVersion()->Unref();
+      iter.cfd->GetSuperVersion()->Unref();
    }
  }
 }
@@ -2040,7 +2120,8 @@ struct CompareKeyContext {
    }

    // Both keys are from the same column family
-    int cmp = comparator->Compare(*(lhs->key), *(rhs->key));
+    int cmp = comparator->CompareWithoutTimestamp(
+        *(lhs->key), /*a_has_ts=*/false, *(rhs->key), /*b_has_ts=*/false);
    if (cmp < 0) {
      return true;
    }
@@ -2072,7 +2153,8 @@ void DBImpl::PrepareMultiGetKeys(
        }

        // Both keys are from the same column family
-        int cmp = comparator->Compare(*(lhs->key), *(rhs->key));
+        int cmp = comparator->CompareWithoutTimestamp(
+            *(lhs->key), /*a_has_ts=*/false, *(rhs->key), /*b_has_ts=*/false);
        assert(cmp <= 0);
      }
      index++;
@@ -2158,14 +2240,24 @@ void DBImpl::MultiGetWithCallback(
    consistent_seqnum = callback->max_visible_seq();
  }

-  MultiGetImpl(read_options, 0, num_keys, sorted_keys,
-               multiget_cf_data[0].super_version, consistent_seqnum, nullptr,
-               nullptr);
+  Status s = MultiGetImpl(read_options, 0, num_keys, sorted_keys,
+                          multiget_cf_data[0].super_version, consistent_seqnum,
+                          nullptr, nullptr);
+  assert(s.ok() || s.IsTimedOut());
  ReturnAndCleanupSuperVersion(multiget_cf_data[0].cfd,
                               multiget_cf_data[0].super_version);
 }

-void DBImpl::MultiGetImpl(
+// The actual implementation of batched MultiGet. Parameters -
+// start_key - Index in the sorted_keys vector to start processing from
+// num_keys - Number of keys to lookup, starting with sorted_keys[start_key]
+// sorted_keys - The entire batch of sorted keys for this CF
+//
+// The per key status is returned in the KeyContext structures pointed to by
+// sorted_keys. An overall Status is also returned, with the only possible
+// values being Status::OK() and Status::TimedOut(). The latter indicates
+// that the call exceeded read_options.deadline
+Status DBImpl::MultiGetImpl(
    const ReadOptions& read_options, size_t start_key, size_t num_keys,
    autovector<KeyContext*, MultiGetContext::MAX_BATCH_SIZE>* sorted_keys,
    SuperVersion* super_version, SequenceNumber snapshot,
@@ -2178,12 +2270,20 @@ void DBImpl::MultiGetImpl(
  // s is both in/out. When in, s could either be OK or MergeInProgress.
  // merge_operands will contain the sequence of merges in the latter case.
  size_t keys_left = num_keys;
+  Status s;
  while (keys_left) {
+    if (read_options.deadline.count() &&
+        env_->NowMicros() >
+            static_cast<uint64_t>(read_options.deadline.count())) {
+      s = Status::TimedOut();
+      break;
+    }
+
    size_t batch_size = (keys_left > MultiGetContext::MAX_BATCH_SIZE)
                            ? MultiGetContext::MAX_BATCH_SIZE
                            : keys_left;
    MultiGetContext ctx(sorted_keys, start_key + num_keys - keys_left,
-                        batch_size, snapshot);
+                        batch_size, snapshot, read_options);
    MultiGetRange range = ctx.GetMultiGetRange();
    bool lookup_current = false;

@@ -2221,13 +2321,21 @@ void DBImpl::MultiGetImpl(
  PERF_TIMER_GUARD(get_post_process_time);
  size_t num_found = 0;
  uint64_t bytes_read = 0;
-  for (size_t i = start_key; i < start_key + num_keys; ++i) {
+  for (size_t i = start_key; i < start_key + num_keys - keys_left; ++i) {
    KeyContext* key = (*sorted_keys)[i];
    if (key->s->ok()) {
      bytes_read += key->value->size();
      num_found++;
    }
  }
+  if (keys_left) {
+    assert(s.IsTimedOut());
+    for (size_t i = start_key + num_keys - keys_left; i < start_key + num_keys;
+         ++i) {
+      KeyContext* key = (*sorted_keys)[i];
+      *key->s = Status::TimedOut();
+    }
+  }

  RecordTick(stats_, NUMBER_MULTIGET_CALLS);
  RecordTick(stats_, NUMBER_MULTIGET_KEYS_READ, num_keys);
@@ -2236,6 +2344,8 @@ void DBImpl::MultiGetImpl(
  RecordInHistogram(stats_, BYTES_PER_MULTIGET, bytes_read);
  PERF_COUNTER_ADD(multiget_read_bytes, bytes_read);
  PERF_TIMER_STOP(get_post_process_time);
+
+  return s;
 }

 Status DBImpl::CreateColumnFamily(const ColumnFamilyOptions& cf_options,
@@ -2524,6 +2634,12 @@ Iterator* DBImpl::NewIterator(const ReadOptions& read_options,
    return NewErrorIterator(
        Status::NotSupported("Managed iterator is not supported anymore."));
  }
+  // We will eventually support deadline for iterators too, but safeguard
+  // for now
+  if (read_options.deadline != std::chrono::microseconds::zero()) {
+    return NewErrorIterator(
+        Status::NotSupported("ReadOptions deadline is not supported"));
+  }
  Iterator* result = nullptr;
  if (read_options.read_tier == kPersistedTier) {
    return NewErrorIterator(Status::NotSupported(
@@ -2548,7 +2664,8 @@ Iterator* DBImpl::NewIterator(const ReadOptions& read_options,

 #else
    SuperVersion* sv = cfd->GetReferencedSuperVersion(this);
-    auto iter = new ForwardIterator(this, read_options, cfd, sv);
+    auto iter = new ForwardIterator(this, read_options, cfd, sv,
+                                    /* allow_unprepared_value */ true);
    result = NewDBIterator(
        env_, read_options, *cfd->ioptions(), sv->mutable_cf_options,
        cfd->user_comparator(), iter, kMaxSequenceNumber,
@@ -2625,7 +2742,8 @@ ArenaWrappedDBIter* DBImpl::NewIteratorImpl(const ReadOptions& read_options,

  InternalIterator* internal_iter =
      NewInternalIterator(read_options, cfd, sv, db_iter->GetArena(),
-                          db_iter->GetRangeDelAggregator(), snapshot);
+                          db_iter->GetRangeDelAggregator(), snapshot,
+                          /* allow_unprepared_value */ true);
  db_iter->SetIterUnderDBIter(internal_iter);

  return db_iter;
@@ -2653,7 +2771,8 @@ Status DBImpl::NewIterators(
    for (auto cfh : column_families) {
      auto cfd = reinterpret_cast<ColumnFamilyHandleImpl*>(cfh)->cfd();
      SuperVersion* sv = cfd->GetReferencedSuperVersion(this);
-      auto iter = new ForwardIterator(this, read_options, cfd, sv);
+      auto iter = new ForwardIterator(this, read_options, cfd, sv,
+                                      /* allow_unprepared_value */ true);
      iterators->push_back(NewDBIterator(
          env_, read_options, *cfd->ioptions(), sv->mutable_cf_options,
          cfd->user_comparator(), iter, kMaxSequenceNumber,
@@ -581,9 +581,14 @@ class DBImpl : public DB {
  // 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.
+  // If allow_unprepared_value is true, the returned iterator may defer reading
+  // the value and so will require PrepareValue() to be called before value();
+  // allow_unprepared_value = false is convenient when this optimization is not
+  // useful, e.g. when reading the whole column family.
  InternalIterator* NewInternalIterator(
      Arena* arena, RangeDelAggregator* range_del_agg, SequenceNumber sequence,
-      ColumnFamilyHandle* column_family = nullptr);
+      ColumnFamilyHandle* column_family = nullptr,
+      bool allow_unprepared_value = false);

  LogsWithPrepTracker* logs_with_prep_tracker() {
    return &logs_with_prep_tracker_;
@@ -709,7 +714,8 @@ class DBImpl : public DB {

  InternalIterator* NewInternalIterator(
      const ReadOptions&, ColumnFamilyData* cfd, SuperVersion* super_version,
-      Arena* arena, RangeDelAggregator* range_del_agg, SequenceNumber sequence);
+      Arena* arena, RangeDelAggregator* range_del_agg, SequenceNumber sequence,
+      bool allow_unprepared_value);

  // hollow transactions shell used for recovery.
  // these will then be passed to TransactionDB so that
@@ -963,6 +969,12 @@ class DBImpl : public DB {
  void TEST_WaitForPersistStatsRun(std::function<void()> callback) const;
  bool TEST_IsPersistentStatsEnabled() const;
  size_t TEST_EstimateInMemoryStatsHistorySize() const;
+
+  VersionSet* TEST_GetVersionSet() const { return versions_.get(); }
+
+  const std::unordered_set<uint64_t>& TEST_GetFilesGrabbedForPurge() const {
+    return files_grabbed_for_purge_;
+  }
 #endif  // NDEBUG

 protected:
@@ -1143,13 +1155,11 @@ class DBImpl : public DB {
  // REQUIRES: db mutex held when calling this function, but the db mutex can
  // be released and re-acquired. Db mutex will be held when the function
  // returns.
-  // Currently, this function should be called only in best-efforts recovery
-  // mode.
  // After best-efforts recovery, there may be SST files in db/cf paths that are
  // not referenced in the MANIFEST. We delete these SST files. In the
  // meantime, we find out the largest file number present in the paths, and
  // bump up the version set's next_file_number_ to be 1 + largest_file_number.
-  Status CleanupFilesAfterRecovery();
+  Status FinishBestEffortsRecovery();

 private:
  friend class DB;
@@ -1763,7 +1773,7 @@ class DBImpl : public DB {
  // to have acquired the SuperVersion and pass in a snapshot sequence number
  // in order to construct the LookupKeys. The start_key and num_keys specify
  // the range of keys in the sorted_keys vector for a single column family.
-  void MultiGetImpl(
+  Status MultiGetImpl(
      const ReadOptions& read_options, size_t start_key, size_t num_keys,
      autovector<KeyContext*, MultiGetContext::MAX_BATCH_SIZE>* sorted_keys,
      SuperVersion* sv, SequenceNumber snap_seqnum, ReadCallback* callback,
@@ -1931,7 +1941,7 @@ class DBImpl : public DB {
  std::unordered_map<uint64_t, PurgeFileInfo> purge_files_;

  // A vector to store the file numbers that have been assigned to certain
-  // JobContext. Current implementation tracks ssts only.
+  // JobContext. Current implementation tracks table and blob files only.
  std::unordered_set<uint64_t> files_grabbed_for_purge_;

  // A queue to store log writers to close
@@ -1906,7 +1906,7 @@ Status DBImpl::WaitForFlushMemTables(
      }
    }
    if (1 == num_dropped && 1 == num) {
-      return Status::InvalidArgument("Cannot flush a dropped CF");
+      return Status::ColumnFamilyDropped();
    }
    // Column families involved in this flush request have either been dropped
    // or finished flush. Then it's time to finish waiting.
@@ -2030,7 +2030,7 @@ void DBImpl::MaybeScheduleFlushOrCompaction() {

 DBImpl::BGJobLimits DBImpl::GetBGJobLimits() const {
  mutex_.AssertHeld();
-  return GetBGJobLimits(immutable_db_options_.max_background_flushes,
+  return GetBGJobLimits(mutable_db_options_.max_background_flushes,
                        mutable_db_options_.max_background_compactions,
                        mutable_db_options_.max_background_jobs,
                        write_controller_.NeedSpeedupCompaction());
@@ -2143,8 +2143,7 @@ void DBImpl::BGWorkFlush(void* arg) {

  IOSTATS_SET_THREAD_POOL_ID(fta.thread_pri_);
  TEST_SYNC_POINT("DBImpl::BGWorkFlush");
-  static_cast_with_check<DBImpl, DB>(fta.db_)->BackgroundCallFlush(
-      fta.thread_pri_);
+  static_cast_with_check<DBImpl>(fta.db_)->BackgroundCallFlush(fta.thread_pri_);
  TEST_SYNC_POINT("DBImpl::BGWorkFlush:done");
 }

@@ -2155,7 +2154,7 @@ void DBImpl::BGWorkCompaction(void* arg) {
  TEST_SYNC_POINT("DBImpl::BGWorkCompaction");
  auto prepicked_compaction =
      static_cast<PrepickedCompaction*>(ca.prepicked_compaction);
-  static_cast_with_check<DBImpl, DB>(ca.db)->BackgroundCallCompaction(
+  static_cast_with_check<DBImpl>(ca.db)->BackgroundCallCompaction(
      prepicked_compaction, Env::Priority::LOW);
  delete prepicked_compaction;
 }
@@ -2549,8 +2548,8 @@ Status DBImpl::BackgroundCompaction(bool* made_progress,
                       "[%s] Manual compaction from level-%d from %s .. "
                       "%s; nothing to do\n",
                       m->cfd->GetName().c_str(), m->input_level,
-                       (m->begin ? m->begin->DebugString().c_str() : "(begin)"),
-                       (m->end ? m->end->DebugString().c_str() : "(end)"));
+                       (m->begin ? m->begin->DebugString(true).c_str() : "(begin)"),
+                       (m->end ? m->end->DebugString(true).c_str() : "(end)"));
    } else {
      // First check if we have enough room to do the compaction
      bool enough_room = EnoughRoomForCompaction(
@@ -2569,11 +2568,11 @@ Status DBImpl::BackgroundCompaction(bool* made_progress,
            "[%s] Manual compaction from level-%d to level-%d from %s .. "
            "%s; will stop at %s\n",
            m->cfd->GetName().c_str(), m->input_level, c->output_level(),
-            (m->begin ? m->begin->DebugString().c_str() : "(begin)"),
-            (m->end ? m->end->DebugString().c_str() : "(end)"),
+            (m->begin ? m->begin->DebugString(true).c_str() : "(begin)"),
+            (m->end ? m->end->DebugString(true).c_str() : "(end)"),
            ((m->done || m->manual_end == nullptr)
                 ? "(end)"
-                 : m->manual_end->DebugString().c_str()));
+                 : m->manual_end->DebugString(true).c_str()));
      }
    }
  } else if (!is_prepicked && !compaction_queue_.empty()) {
@@ -36,7 +36,7 @@ uint64_t DBImpl::MinObsoleteSstNumberToKeep() {
  return std::numeric_limits<uint64_t>::max();
 }

-// * Returns the list of live files in 'sst_live'
+// * Returns the list of live files in 'sst_live' and 'blob_live'.
 // If it's doing full scan:
 // * Returns the list of all files in the filesystem in
 // 'full_scan_candidate_files'.
@@ -77,26 +77,26 @@ void DBImpl::FindObsoleteFiles(JobContext* job_context, bool force,
  // Since job_context->min_pending_output is set, until file scan finishes,
  // mutex_ cannot be released. Otherwise, we might see no min_pending_output
  // here but later find newer generated unfinalized files while scanning.
-  if (!pending_outputs_.empty()) {
-    job_context->min_pending_output = *pending_outputs_.begin();
-  } else {
-    // delete all of them
-    job_context->min_pending_output = std::numeric_limits<uint64_t>::max();
-  }
+  job_context->min_pending_output = MinObsoleteSstNumberToKeep();

  // Get obsolete files.  This function will also update the list of
  // pending files in VersionSet().
-  versions_->GetObsoleteFiles(&job_context->sst_delete_files,
-                              &job_context->manifest_delete_files,
-                              job_context->min_pending_output);
+  versions_->GetObsoleteFiles(
+      &job_context->sst_delete_files, &job_context->blob_delete_files,
+      &job_context->manifest_delete_files, job_context->min_pending_output);

-  // Mark the elements in job_context->sst_delete_files as grabbedForPurge
-  // so that other threads calling FindObsoleteFiles with full_scan=true
-  // will not add these files to candidate list for purge.
+  // Mark the elements in job_context->sst_delete_files and
+  // job_context->blob_delete_files as "grabbed for purge" so that other threads
+  // calling FindObsoleteFiles with full_scan=true will not add these files to
+  // candidate list for purge.
  for (const auto& sst_to_del : job_context->sst_delete_files) {
    MarkAsGrabbedForPurge(sst_to_del.metadata->fd.GetNumber());
  }

+  for (const auto& blob_file : job_context->blob_delete_files) {
+    MarkAsGrabbedForPurge(blob_file.GetBlobFileNumber());
+  }
+
  // store the current filenum, lognum, etc
  job_context->manifest_file_number = versions_->manifest_file_number();
  job_context->pending_manifest_file_number =
@@ -104,7 +104,7 @@ void DBImpl::FindObsoleteFiles(JobContext* job_context, bool force,
  job_context->log_number = MinLogNumberToKeep();
  job_context->prev_log_number = versions_->prev_log_number();

-  versions_->AddLiveFiles(&job_context->sst_live);
+  versions_->AddLiveFiles(&job_context->sst_live, &job_context->blob_live);
  if (doing_the_full_scan) {
    InfoLogPrefix info_log_prefix(!immutable_db_options_.db_log_dir.empty(),
                                  dbname_);
@@ -257,8 +257,11 @@ bool CompareCandidateFile(const JobContext::CandidateFileInfo& first,
 void DBImpl::DeleteObsoleteFileImpl(int job_id, const std::string& fname,
                                    const std::string& path_to_sync,
                                    FileType type, uint64_t number) {
+  TEST_SYNC_POINT_CALLBACK("DBImpl::DeleteObsoleteFileImpl::BeforeDeletion",
+                           const_cast<std::string*>(&fname));
+
  Status file_deletion_status;
-  if (type == kTableFile || type == kLogFile) {
+  if (type == kTableFile || type == kBlobFile || type == kLogFile) {
    file_deletion_status =
        DeleteDBFile(&immutable_db_options_, fname, path_to_sync,
                     /*force_bg=*/false, /*force_fg=*/!wal_in_db_path_);
@@ -304,19 +307,19 @@ void DBImpl::PurgeObsoleteFiles(JobContext& state, bool schedule_only) {
  // FindObsoleteFiles() should've populated this so nonzero
  assert(state.manifest_file_number != 0);

-  // Now, convert live list to an unordered map, WITHOUT mutex held;
-  // set is slow.
-  std::unordered_map<uint64_t, const FileDescriptor*> sst_live_map;
-  for (const FileDescriptor& fd : state.sst_live) {
-    sst_live_map[fd.GetNumber()] = &fd;
-  }
+  // Now, convert lists to unordered sets, WITHOUT mutex held; set is slow.
+  std::unordered_set<uint64_t> sst_live_set(state.sst_live.begin(),
+                                            state.sst_live.end());
+  std::unordered_set<uint64_t> blob_live_set(state.blob_live.begin(),
+                                             state.blob_live.end());
  std::unordered_set<uint64_t> log_recycle_files_set(
      state.log_recycle_files.begin(), state.log_recycle_files.end());

  auto candidate_files = state.full_scan_candidate_files;
  candidate_files.reserve(
      candidate_files.size() + state.sst_delete_files.size() +
-      state.log_delete_files.size() + state.manifest_delete_files.size());
+      state.blob_delete_files.size() + state.log_delete_files.size() +
+      state.manifest_delete_files.size());
  // We may ignore the dbname when generating the file names.
  for (auto& file : state.sst_delete_files) {
    candidate_files.emplace_back(
@@ -327,6 +330,11 @@ void DBImpl::PurgeObsoleteFiles(JobContext& state, bool schedule_only) {
    file.DeleteMetadata();
  }

+  for (const auto& blob_file : state.blob_delete_files) {
+    candidate_files.emplace_back(BlobFileName(blob_file.GetBlobFileNumber()),
+                                 blob_file.GetPath());
+  }
+
  for (auto file_num : state.log_delete_files) {
    if (file_num > 0) {
      candidate_files.emplace_back(LogFileName(file_num),
@@ -413,12 +421,19 @@ void DBImpl::PurgeObsoleteFiles(JobContext& state, bool schedule_only) {
      case kTableFile:
        // If the second condition is not there, this makes
        // DontDeletePendingOutputs fail
-        keep = (sst_live_map.find(number) != sst_live_map.end()) ||
+        keep = (sst_live_set.find(number) != sst_live_set.end()) ||
               number >= state.min_pending_output;
        if (!keep) {
          files_to_del.insert(number);
        }
        break;
+      case kBlobFile:
+        keep = number >= state.min_pending_output ||
+               (blob_live_set.find(number) != blob_live_set.end());
+        if (!keep) {
+          files_to_del.insert(number);
+        }
+        break;
      case kTempFile:
        // Any temp files that are currently being written to must
        // be recorded in pending_outputs_, which is inserted into "live".
@@ -428,7 +443,8 @@ void DBImpl::PurgeObsoleteFiles(JobContext& state, bool schedule_only) {
        //
        // TODO(yhchiang): carefully modify the third condition to safely
        //                 remove the temp options files.
-        keep = (sst_live_map.find(number) != sst_live_map.end()) ||
+        keep = (sst_live_set.find(number) != sst_live_set.end()) ||
+               (blob_live_set.find(number) != blob_live_set.end()) ||
               (number == state.pending_manifest_file_number) ||
               (to_delete.find(kOptionsFileNamePrefix) != std::string::npos);
        break;
@@ -451,7 +467,6 @@ void DBImpl::PurgeObsoleteFiles(JobContext& state, bool schedule_only) {
      case kDBLockFile:
      case kIdentityFile:
      case kMetaDatabase:
-      case kBlobFile:
        keep = true;
        break;
    }
@@ -467,6 +482,9 @@ void DBImpl::PurgeObsoleteFiles(JobContext& state, bool schedule_only) {
      TableCache::Evict(table_cache_.get(), number);
      fname = MakeTableFileName(candidate_file.file_path, number);
      dir_to_sync = candidate_file.file_path;
+    } else if (type == kBlobFile) {
+      fname = BlobFileName(candidate_file.file_path, number);
+      dir_to_sync = candidate_file.file_path;
    } else {
      dir_to_sync =
          (type == kLogFile) ? immutable_db_options_.wal_dir : dbname_;
@@ -665,7 +683,7 @@ uint64_t PrecomputeMinLogNumberToKeep(
  return min_log_number_to_keep;
 }

-Status DBImpl::CleanupFilesAfterRecovery() {
+Status DBImpl::FinishBestEffortsRecovery() {
  mutex_.AssertHeld();
  std::vector<std::string> paths;
  paths.push_back(dbname_);
@@ -704,8 +722,22 @@ Status DBImpl::CleanupFilesAfterRecovery() {
  if (largest_file_number > next_file_number) {
    versions_->next_file_number_.store(largest_file_number + 1);
  }
+
+  VersionEdit edit;
+  edit.SetNextFile(versions_->next_file_number_.load());
+  assert(versions_->GetColumnFamilySet());
+  ColumnFamilyData* default_cfd = versions_->GetColumnFamilySet()->GetDefault();
+  assert(default_cfd);
+  // Even if new_descriptor_log is false, we will still switch to a new
+  // MANIFEST and update CURRENT file, since this is in recovery.
+  Status s = versions_->LogAndApply(
+      default_cfd, *default_cfd->GetLatestMutableCFOptions(), &edit, &mutex_,
+      directories_.GetDbDir(), /*new_descriptor_log*/ false);
+  if (!s.ok()) {
+    return s;
+  }
+
  mutex_.Unlock();
-  Status s;
  for (const auto& fname : files_to_delete) {
    s = env_->DeleteFile(fname);
    if (!s.ok()) {
@@ -425,7 +425,7 @@ Status DBImpl::Recover(
    s = versions_->TryRecover(column_families, read_only, &db_id_,
                              &missing_table_file);
    if (s.ok()) {
-      s = CleanupFilesAfterRecovery();
+      s = FinishBestEffortsRecovery();
    }
  }
  if (!s.ok()) {
@@ -87,7 +87,8 @@ Iterator* DBImplReadOnly::NewIterator(const ReadOptions& read_options,
      super_version->version_number, read_callback);
  auto internal_iter =
      NewInternalIterator(read_options, cfd, super_version, db_iter->GetArena(),
-                          db_iter->GetRangeDelAggregator(), read_seq);
+                          db_iter->GetRangeDelAggregator(), read_seq,
+                          /* allow_unprepared_value */ true);
  db_iter->SetIterUnderDBIter(internal_iter);
  return db_iter;
 }
@@ -118,7 +119,8 @@ Status DBImplReadOnly::NewIterators(
        sv->version_number, read_callback);
    auto* internal_iter =
        NewInternalIterator(read_options, cfd, sv, db_iter->GetArena(),
-                            db_iter->GetRangeDelAggregator(), read_seq);
+                            db_iter->GetRangeDelAggregator(), read_seq,
+                            /* allow_unprepared_value */ true);
    db_iter->SetIterUnderDBIter(internal_iter);
    iterators->push_back(db_iter);
  }
@@ -417,7 +417,8 @@ ArenaWrappedDBIter* DBImplSecondary::NewIteratorImpl(
      super_version->version_number, read_callback);
  auto internal_iter =
      NewInternalIterator(read_options, cfd, super_version, db_iter->GetArena(),
-                          db_iter->GetRangeDelAggregator(), snapshot);
+                          db_iter->GetRangeDelAggregator(), snapshot,
+                          /* allow_unprepared_value */ true);
  db_iter->SetIterUnderDBIter(internal_iter);
  return db_iter;
 }
@@ -1820,6 +1820,8 @@ Status DB::Put(const WriteOptions& opt, ColumnFamilyHandle* column_family,
  const Slice* ts = opt.timestamp;
  assert(nullptr != ts);
  size_t ts_sz = ts->size();
+  assert(column_family->GetComparator());
+  assert(ts_sz == column_family->GetComparator()->timestamp_size());
  WriteBatch batch(key.size() + ts_sz + value.size() + 24, /*max_bytes=*/0,
                   ts_sz);
  Status s = batch.Put(column_family, key, value);
@@ -45,6 +45,8 @@ class DBSecondaryTest : public DBTestBase {

  void OpenSecondary(const Options& options);

+  Status TryOpenSecondary(const Options& options);
+
  void OpenSecondaryWithColumnFamilies(
      const std::vector<std::string>& column_families, const Options& options);

@@ -70,9 +72,13 @@ class DBSecondaryTest : public DBTestBase {
 };

 void DBSecondaryTest::OpenSecondary(const Options& options) {
+  ASSERT_OK(TryOpenSecondary(options));
+}
+
+Status DBSecondaryTest::TryOpenSecondary(const Options& options) {
  Status s =
      DB::OpenAsSecondary(options, dbname_, secondary_path_, &db_secondary_);
-  ASSERT_OK(s);
+  return s;
 }

 void DBSecondaryTest::OpenSecondaryWithColumnFamilies(
@@ -858,6 +864,56 @@ TEST_F(DBSecondaryTest, CheckConsistencyWhenOpen) {
  thread.join();
  ASSERT_TRUE(called);
 }
+
+TEST_F(DBSecondaryTest, StartFromInconsistent) {
+  Options options = CurrentOptions();
+  DestroyAndReopen(options);
+  ASSERT_OK(Put("foo", "value"));
+  ASSERT_OK(Flush());
+  SyncPoint::GetInstance()->DisableProcessing();
+  SyncPoint::GetInstance()->ClearAllCallBacks();
+  SyncPoint::GetInstance()->SetCallBack(
+      "VersionBuilder::CheckConsistencyBeforeReturn", [&](void* arg) {
+        ASSERT_NE(nullptr, arg);
+        *(reinterpret_cast<Status*>(arg)) =
+            Status::Corruption("Inject corruption");
+      });
+  SyncPoint::GetInstance()->EnableProcessing();
+  Options options1;
+  Status s = TryOpenSecondary(options1);
+  ASSERT_TRUE(s.IsCorruption());
+}
+
+TEST_F(DBSecondaryTest, InconsistencyDuringCatchUp) {
+  Options options = CurrentOptions();
+  DestroyAndReopen(options);
+  ASSERT_OK(Put("foo", "value"));
+  ASSERT_OK(Flush());
+
+  Options options1;
+  OpenSecondary(options1);
+
+  {
+    std::string value;
+    ASSERT_OK(db_secondary_->Get(ReadOptions(), "foo", &value));
+    ASSERT_EQ("value", value);
+  }
+
+  ASSERT_OK(Put("bar", "value1"));
+  ASSERT_OK(Flush());
+
+  SyncPoint::GetInstance()->DisableProcessing();
+  SyncPoint::GetInstance()->ClearAllCallBacks();
+  SyncPoint::GetInstance()->SetCallBack(
+      "VersionBuilder::CheckConsistencyBeforeReturn", [&](void* arg) {
+        ASSERT_NE(nullptr, arg);
+        *(reinterpret_cast<Status*>(arg)) =
+            Status::Corruption("Inject corruption");
+      });
+  SyncPoint::GetInstance()->EnableProcessing();
+  Status s = db_secondary_->TryCatchUpWithPrimary();
+  ASSERT_TRUE(s.IsCorruption());
+}
 #endif  //! ROCKSDB_LITE

 }  // namespace ROCKSDB_NAMESPACE
@@ -73,6 +73,7 @@ DBIter::DBIter(Env* _env, const ReadOptions& read_options,
      cfd_(cfd),
      start_seqnum_(read_options.iter_start_seqnum),
      timestamp_ub_(read_options.timestamp),
+      timestamp_lb_(read_options.iter_start_ts),
      timestamp_size_(timestamp_ub_ ? timestamp_ub_->size() : 0) {
  RecordTick(statistics_, NO_ITERATOR_CREATED);
  if (pin_thru_lifetime_) {
@@ -246,23 +247,31 @@ bool DBIter::FindNextUserEntryInternal(bool skipping_saved_key,

    assert(ikey_.user_key.size() >= timestamp_size_);
    Slice ts;
+    bool more_recent = false;
    if (timestamp_size_ > 0) {
      ts = ExtractTimestampFromUserKey(ikey_.user_key, timestamp_size_);
    }
-    if (IsVisible(ikey_.sequence, ts)) {
+    if (IsVisible(ikey_.sequence, ts, &more_recent)) {
      // If the previous entry is of seqnum 0, the current entry will not
      // possibly be skipped. This condition can potentially be relaxed to
      // prev_key.seq <= ikey_.sequence. We are cautious because it will be more
      // prone to bugs causing the same user key with the same sequence number.
-      if (!is_prev_key_seqnum_zero && skipping_saved_key &&
-          user_comparator_.CompareWithoutTimestamp(
-              ikey_.user_key, saved_key_.GetUserKey()) <= 0) {
+      // Note that with current timestamp implementation, the same user key can
+      // have different timestamps and zero sequence number on the bottommost
+      // level. This will change in the future.
+      if ((!is_prev_key_seqnum_zero || timestamp_size_ > 0) &&
+          skipping_saved_key &&
+          CompareKeyForSkip(ikey_.user_key, saved_key_.GetUserKey()) <= 0) {
        num_skipped++;  // skip this entry
        PERF_COUNTER_ADD(internal_key_skipped_count, 1);
      } else {
        assert(!skipping_saved_key ||
-               user_comparator_.CompareWithoutTimestamp(
-                   ikey_.user_key, saved_key_.GetUserKey()) > 0);
+               CompareKeyForSkip(ikey_.user_key, saved_key_.GetUserKey()) > 0);
+        if (!iter_.PrepareValue()) {
+          assert(!iter_.status().ok());
+          valid_ = false;
+          return false;
+        }
        num_skipped = 0;
        reseek_done = false;
        switch (ikey_.type) {
@@ -363,11 +372,13 @@ bool DBIter::FindNextUserEntryInternal(bool skipping_saved_key,
        }
      }
    } else {
-      PERF_COUNTER_ADD(internal_recent_skipped_count, 1);
+      if (more_recent) {
+        PERF_COUNTER_ADD(internal_recent_skipped_count, 1);
+      }

-      // This key was inserted after our snapshot was taken.
-      // If this happens too many times in a row for the same user key, we want
-      // to seek to the target sequence number.
+      // This key was inserted after our snapshot was taken or skipped by
+      // timestamp range. If this happens too many times in a row for the same
+      // user key, we want to seek to the target sequence number.
      int cmp = user_comparator_.CompareWithoutTimestamp(
          ikey_.user_key, saved_key_.GetUserKey());
      if (cmp == 0 || (skipping_saved_key && cmp < 0)) {
@@ -446,6 +457,7 @@ bool DBIter::FindNextUserEntryInternal(bool skipping_saved_key,
 // Scan from the newer entries to older entries.
 // PRE: iter_.key() points to the first merge type entry
 //      saved_key_ stores the user key
+//      iter_.PrepareValue() has been called
 // POST: saved_value_ has the merged value for the user key
 //       iter_ points to the next entry (or invalid)
 bool DBIter::MergeValuesNewToOld() {
@@ -475,14 +487,21 @@ bool DBIter::MergeValuesNewToOld() {
    if (!user_comparator_.Equal(ikey.user_key, saved_key_.GetUserKey())) {
      // hit the next user key, stop right here
      break;
-    } else if (kTypeDeletion == ikey.type || kTypeSingleDeletion == ikey.type ||
+    }
+    if (kTypeDeletion == ikey.type || kTypeSingleDeletion == ikey.type ||
               range_del_agg_.ShouldDelete(
                   ikey, RangeDelPositioningMode::kForwardTraversal)) {
      // hit a delete with the same user key, stop right here
      // iter_ is positioned after delete
      iter_.Next();
      break;
-    } else if (kTypeValue == ikey.type) {
+    }
+    if (!iter_.PrepareValue()) {
+      valid_ = false;
+      return false;
+    }
+
+    if (kTypeValue == ikey.type) {
      // hit a put, merge the put value with operands and store the
      // final result in saved_value_. We are done!
      const Slice val = iter_.value();
@@ -754,6 +773,11 @@ bool DBIter::FindValueForCurrentKey() {
      return FindValueForCurrentKeyUsingSeek();
    }

+    if (!iter_.PrepareValue()) {
+      valid_ = false;
+      return false;
+    }
+
    last_key_entry_type = ikey.type;
    switch (last_key_entry_type) {
      case kTypeValue:
@@ -931,6 +955,10 @@ bool DBIter::FindValueForCurrentKeyUsingSeek() {
    valid_ = false;
    return false;
  }
+  if (!iter_.PrepareValue()) {
+    valid_ = false;
+    return false;
+  }
  if (ikey.type == kTypeValue || ikey.type == kTypeBlobIndex) {
    assert(iter_.iter()->IsValuePinned());
    pinned_value_ = iter_.value();
@@ -962,12 +990,17 @@ bool DBIter::FindValueForCurrentKeyUsingSeek() {
    if (!user_comparator_.Equal(ikey.user_key, saved_key_.GetUserKey())) {
      break;
    }
-
    if (ikey.type == kTypeDeletion || ikey.type == kTypeSingleDeletion ||
        range_del_agg_.ShouldDelete(
            ikey, RangeDelPositioningMode::kForwardTraversal)) {
      break;
-    } else if (ikey.type == kTypeValue) {
+    }
+    if (!iter_.PrepareValue()) {
+      valid_ = false;
+      return false;
+    }
+
+    if (ikey.type == kTypeValue) {
      const Slice val = iter_.value();
      Status s = MergeHelper::TimedFullMerge(
          merge_operator_, saved_key_.GetUserKey(), &val,
@@ -1101,20 +1134,24 @@ bool DBIter::TooManyInternalKeysSkipped(bool increment) {
  return false;
 }

-bool DBIter::IsVisible(SequenceNumber sequence, const Slice& ts) {
+bool DBIter::IsVisible(SequenceNumber sequence, const Slice& ts,
+                       bool* more_recent) {
  // Remember that comparator orders preceding timestamp as larger.
-  int cmp_ts = timestamp_ub_ != nullptr
-                   ? user_comparator_.CompareTimestamp(ts, *timestamp_ub_)
-                   : 0;
-  if (cmp_ts > 0) {
-    return false;
-  }
-  if (read_callback_ == nullptr) {
-    return sequence <= sequence_;
-  } else {
-    // TODO(yanqin): support timestamp in read_callback_.
-    return read_callback_->IsVisible(sequence);
+  // TODO(yanqin): support timestamp in read_callback_.
+  bool visible_by_seq = (read_callback_ == nullptr)
+                            ? sequence <= sequence_
+                            : read_callback_->IsVisible(sequence);
+
+  bool visible_by_ts =
+      (timestamp_ub_ == nullptr ||
+       user_comparator_.CompareTimestamp(ts, *timestamp_ub_) <= 0) &&
+      (timestamp_lb_ == nullptr ||
+       user_comparator_.CompareTimestamp(ts, *timestamp_lb_) >= 0);
+
+  if (more_recent) {
+    *more_recent = !visible_by_seq;
  }
+  return visible_by_seq && visible_by_ts;
 }

 void DBIter::SetSavedKeyToSeekTarget(const Slice& target) {
@@ -231,7 +231,8 @@ class DBIter final : public Iterator {
  // entry can be found within the prefix.
  void PrevInternal(const Slice* prefix);
  bool TooManyInternalKeysSkipped(bool increment = true);
-  bool IsVisible(SequenceNumber sequence, const Slice& ts);
+  bool IsVisible(SequenceNumber sequence, const Slice& ts,
+                 bool* more_recent = nullptr);

  // Temporarily pin the blocks that we encounter until ReleaseTempPinnedData()
  // is called
@@ -270,6 +271,15 @@ class DBIter final : public Iterator {
    return expect_total_order_inner_iter_;
  }

+  // If lower bound of timestamp is given by ReadOptions.iter_start_ts, we need
+  // to return versions of the same key. We cannot just skip if the key value
+  // is the same but timestamps are different but fall in timestamp range.
+  inline int CompareKeyForSkip(const Slice& a, const Slice& b) {
+    return timestamp_lb_ != nullptr
+               ? user_comparator_.Compare(a, b)
+               : user_comparator_.CompareWithoutTimestamp(a, b);
+  }
+
  const SliceTransform* prefix_extractor_;
  Env* const env_;
  Logger* logger_;
@@ -338,6 +348,7 @@ class DBIter final : public Iterator {
  // if this value > 0 iterator will return internal keys
  SequenceNumber start_seqnum_;
  const Slice* const timestamp_ub_;
+  const Slice* const timestamp_lb_;
  const size_t timestamp_size_;
 };

@@ -1167,32 +1167,62 @@ TEST_P(DBIteratorTest, IndexWithFirstKey) {
    ropt.tailing = tailing;
    std::unique_ptr<Iterator> iter(NewIterator(ropt));

+    ropt.read_tier = ReadTier::kBlockCacheTier;
+    std::unique_ptr<Iterator> nonblocking_iter(NewIterator(ropt));
+
    iter->Seek("b10");
    ASSERT_TRUE(iter->Valid());
    EXPECT_EQ("b2", iter->key().ToString());
    EXPECT_EQ("y2", iter->value().ToString());
    EXPECT_EQ(1, stats->getTickerCount(BLOCK_CACHE_DATA_MISS));

+    // The cache-only iterator should succeed too, using the blocks pulled into
+    // the cache by the previous iterator.
+    nonblocking_iter->Seek("b10");
+    ASSERT_TRUE(nonblocking_iter->Valid());
+    EXPECT_EQ("b2", nonblocking_iter->key().ToString());
+    EXPECT_EQ("y2", nonblocking_iter->value().ToString());
+    EXPECT_EQ(1, stats->getTickerCount(BLOCK_CACHE_DATA_HIT));
+
+    // ... but it shouldn't be able to step forward since the next block is
+    // not in cache yet.
+    nonblocking_iter->Next();
+    ASSERT_FALSE(nonblocking_iter->Valid());
+    ASSERT_TRUE(nonblocking_iter->status().IsIncomplete());
+
+    // ... nor should a seek to the next key succeed.
+    nonblocking_iter->Seek("b20");
+    ASSERT_FALSE(nonblocking_iter->Valid());
+    ASSERT_TRUE(nonblocking_iter->status().IsIncomplete());
+
    iter->Next();
    ASSERT_TRUE(iter->Valid());
    EXPECT_EQ("b3", iter->key().ToString());
    EXPECT_EQ("y3", iter->value().ToString());
-    EXPECT_EQ(2, stats->getTickerCount(BLOCK_CACHE_DATA_MISS));
-    EXPECT_EQ(0, stats->getTickerCount(BLOCK_CACHE_DATA_HIT));
+    EXPECT_EQ(4, stats->getTickerCount(BLOCK_CACHE_DATA_MISS));
+    EXPECT_EQ(1, stats->getTickerCount(BLOCK_CACHE_DATA_HIT));
+
+    // After the blocking iterator loaded the next block, the nonblocking
+    // iterator's seek should succeed.
+    nonblocking_iter->Seek("b20");
+    ASSERT_TRUE(nonblocking_iter->Valid());
+    EXPECT_EQ("b3", nonblocking_iter->key().ToString());
+    EXPECT_EQ("y3", nonblocking_iter->value().ToString());
+    EXPECT_EQ(2, stats->getTickerCount(BLOCK_CACHE_DATA_HIT));

    iter->Seek("c0");
    ASSERT_TRUE(iter->Valid());
    EXPECT_EQ("c0", iter->key().ToString());
    EXPECT_EQ("z1,z2", iter->value().ToString());
-    EXPECT_EQ(0, stats->getTickerCount(BLOCK_CACHE_DATA_HIT));
-    EXPECT_EQ(4, stats->getTickerCount(BLOCK_CACHE_DATA_MISS));
+    EXPECT_EQ(2, stats->getTickerCount(BLOCK_CACHE_DATA_HIT));
+    EXPECT_EQ(6, stats->getTickerCount(BLOCK_CACHE_DATA_MISS));

    iter->Next();
    ASSERT_TRUE(iter->Valid());
    EXPECT_EQ("c3", iter->key().ToString());
    EXPECT_EQ("z3", iter->value().ToString());
-    EXPECT_EQ(0, stats->getTickerCount(BLOCK_CACHE_DATA_HIT));
-    EXPECT_EQ(5, stats->getTickerCount(BLOCK_CACHE_DATA_MISS));
+    EXPECT_EQ(2, stats->getTickerCount(BLOCK_CACHE_DATA_HIT));
+    EXPECT_EQ(7, stats->getTickerCount(BLOCK_CACHE_DATA_MISS));

    iter.reset();

@@ -1207,13 +1237,13 @@ TEST_P(DBIteratorTest, IndexWithFirstKey) {
    ASSERT_TRUE(iter->Valid());
    EXPECT_EQ("b2", iter->key().ToString());
    EXPECT_EQ("y2", iter->value().ToString());
-    EXPECT_EQ(1, stats->getTickerCount(BLOCK_CACHE_DATA_HIT));
-    EXPECT_EQ(5, stats->getTickerCount(BLOCK_CACHE_DATA_MISS));
+    EXPECT_EQ(3, stats->getTickerCount(BLOCK_CACHE_DATA_HIT));
+    EXPECT_EQ(7, stats->getTickerCount(BLOCK_CACHE_DATA_MISS));

    iter->Next();
    ASSERT_FALSE(iter->Valid());
-    EXPECT_EQ(1, stats->getTickerCount(BLOCK_CACHE_DATA_HIT));
-    EXPECT_EQ(5, stats->getTickerCount(BLOCK_CACHE_DATA_MISS));
+    EXPECT_EQ(3, stats->getTickerCount(BLOCK_CACHE_DATA_HIT));
+    EXPECT_EQ(7, stats->getTickerCount(BLOCK_CACHE_DATA_MISS));
  }
 }

@@ -33,13 +33,14 @@ class DBOptionsTest : public DBTestBase {
  std::unordered_map<std::string, std::string> GetMutableDBOptionsMap(
      const DBOptions& options) {
    std::string options_str;
-    GetStringFromDBOptions(&options_str, options);
+    ConfigOptions config_options;
+    config_options.delimiter = "; ";
+    GetStringFromDBOptions(config_options, options, &options_str);
    std::unordered_map<std::string, std::string> options_map;
    StringToMap(options_str, &options_map);
    std::unordered_map<std::string, std::string> mutable_map;
    for (const auto opt : db_options_type_info) {
-      if (opt.second.is_mutable &&
-          opt.second.verification != OptionVerificationType::kDeprecated) {
+      if (opt.second.IsMutable() && opt.second.ShouldSerialize()) {
        mutable_map[opt.first] = options_map[opt.first];
      }
    }
@@ -49,13 +50,15 @@ class DBOptionsTest : public DBTestBase {
  std::unordered_map<std::string, std::string> GetMutableCFOptionsMap(
      const ColumnFamilyOptions& options) {
    std::string options_str;
-    GetStringFromColumnFamilyOptions(&options_str, options);
+    ConfigOptions config_options;
+    config_options.delimiter = "; ";
+
+    GetStringFromColumnFamilyOptions(config_options, options, &options_str);
    std::unordered_map<std::string, std::string> options_map;
    StringToMap(options_str, &options_map);
    std::unordered_map<std::string, std::string> mutable_map;
    for (const auto opt : cf_options_type_info) {
-      if (opt.second.is_mutable &&
-          opt.second.verification != OptionVerificationType::kDeprecated) {
+      if (opt.second.IsMutable() && opt.second.ShouldSerialize()) {
        mutable_map[opt.first] = options_map[opt.first];
      }
    }
@@ -404,6 +407,20 @@ TEST_F(DBOptionsTest, SetBackgroundCompactionThreads) {
  ASSERT_EQ(3, dbfull()->TEST_BGCompactionsAllowed());
 }

+TEST_F(DBOptionsTest, SetBackgroundFlushThreads) {
+  Options options;
+  options.create_if_missing = true;
+  options.max_background_flushes = 1;
+  options.env = env_;
+  Reopen(options);
+  ASSERT_EQ(1, dbfull()->TEST_BGFlushesAllowed());
+  ASSERT_EQ(1, env_->GetBackgroundThreads(Env::Priority::HIGH));
+  ASSERT_OK(dbfull()->SetDBOptions({{"max_background_flushes", "3"}}));
+  ASSERT_EQ(3, env_->GetBackgroundThreads(Env::Priority::HIGH));
+  ASSERT_EQ(3, dbfull()->TEST_BGFlushesAllowed());
+}
+
+
 TEST_F(DBOptionsTest, SetBackgroundJobs) {
  Options options;
  options.create_if_missing = true;
@@ -859,8 +876,6 @@ TEST_F(DBOptionsTest, FIFOTtlBackwardCompatible) {
  ASSERT_EQ(dbfull()->GetOptions().ttl, 191);
 }

-#endif  // ROCKSDB_LITE
-
 TEST_F(DBOptionsTest, ChangeCompression) {
  if (!Snappy_Supported() || !LZ4_Supported()) {
    return;
@@ -872,6 +887,7 @@ TEST_F(DBOptionsTest, ChangeCompression) {
  options.compression = CompressionType::kLZ4Compression;
  options.bottommost_compression = CompressionType::kNoCompression;
  options.bottommost_compression_opts.level = 2;
+  options.bottommost_compression_opts.parallel_threads = 1;

  ASSERT_OK(TryReopen(options));

@@ -897,12 +913,14 @@ TEST_F(DBOptionsTest, ChangeCompression) {
  ASSERT_TRUE(compacted);
  ASSERT_EQ(CompressionType::kNoCompression, compression_used);
  ASSERT_EQ(options.compression_opts.level, compression_opt_used.level);
+  ASSERT_EQ(options.compression_opts.parallel_threads,
+            compression_opt_used.parallel_threads);

  compression_used = CompressionType::kLZ4Compression;
  compacted = false;
  ASSERT_OK(dbfull()->SetOptions(
      {{"bottommost_compression", "kSnappyCompression"},
-       {"bottommost_compression_opts", "0:6:0:0:0:true"}}));
+       {"bottommost_compression_opts", "0:6:0:0:4:true"}}));
  ASSERT_OK(Put("foo", "foofoofoo"));
  ASSERT_OK(Put("bar", "foofoofoo"));
  ASSERT_OK(Flush());
@@ -913,10 +931,13 @@ TEST_F(DBOptionsTest, ChangeCompression) {
  ASSERT_TRUE(compacted);
  ASSERT_EQ(CompressionType::kSnappyCompression, compression_used);
  ASSERT_EQ(6, compression_opt_used.level);
+  // Right now parallel_level is not yet allowed to be changed.

  SyncPoint::GetInstance()->DisableProcessing();
 }

+#endif  // ROCKSDB_LITE
+
 }  // namespace ROCKSDB_NAMESPACE

 int main(int argc, char** argv) {
@@ -47,6 +47,21 @@ TEST_F(DBRangeDelTest, WriteBatchWithIndexNotSupported) {
  ASSERT_TRUE(indexedBatch.DeleteRange("dr1", "dr1").IsNotSupported());
 }

+TEST_F(DBRangeDelTest, EndSameAsStartCoversNothing) {
+  ASSERT_OK(db_->Put(WriteOptions(), "b", "val"));
+  ASSERT_OK(
+      db_->DeleteRange(WriteOptions(), db_->DefaultColumnFamily(), "b", "b"));
+  ASSERT_EQ("val", Get("b"));
+}
+
+TEST_F(DBRangeDelTest, EndComesBeforeStartInvalidArgument) {
+  db_->Put(WriteOptions(), "b", "val");
+  ASSERT_TRUE(
+      db_->DeleteRange(WriteOptions(), db_->DefaultColumnFamily(), "b", "a")
+          .IsInvalidArgument());
+  ASSERT_EQ("val", Get("b"));
+}
+
 TEST_F(DBRangeDelTest, FlushOutputHasOnlyRangeTombstones) {
  do {
    DestroyAndReopen(CurrentOptions());
@@ -356,37 +356,25 @@ TEST_F(DBSSTTest, RateLimitedDelete) {
      "InstrumentedCondVar::TimedWaitInternal", [&](void* arg) {
        // Turn timed wait into a simulated sleep
        uint64_t* abs_time_us = static_cast<uint64_t*>(arg);
-        int64_t cur_time = 0;
-        env_->GetCurrentTime(&cur_time);
-        if (*abs_time_us > static_cast<uint64_t>(cur_time)) {
-          env_->addon_time_.fetch_add(*abs_time_us -
-                                      static_cast<uint64_t>(cur_time));
+        uint64_t cur_time = env_->NowMicros();
+        if (*abs_time_us > cur_time) {
+          env_->addon_time_.fetch_add(*abs_time_us - cur_time);
        }

        // Randomly sleep shortly
        env_->addon_time_.fetch_add(
            static_cast<uint64_t>(Random::GetTLSInstance()->Uniform(10)));

-        // Set wait until time to before current to force not to sleep.
-        int64_t real_cur_time = 0;
-        Env::Default()->GetCurrentTime(&real_cur_time);
-        *abs_time_us = static_cast<uint64_t>(real_cur_time);
+        // Set wait until time to before (actual) current time to force not
+        // to sleep
+        *abs_time_us = Env::Default()->NowMicros();
      });

  ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->EnableProcessing();

-  env_->no_slowdown_ = true;
-  env_->time_elapse_only_sleep_ = true;
  Options options = CurrentOptions();
+  env_->SetTimeElapseOnlySleep(&options);
  options.disable_auto_compactions = true;
-  // Need to disable stats dumping and persisting which also use
-  // RepeatableThread, one of whose member variables is of type
-  // InstrumentedCondVar. The callback for
-  // InstrumentedCondVar::TimedWaitInternal can be triggered by stats dumping
-  // and persisting threads and cause time_spent_deleting measurement to become
-  // incorrect.
-  options.stats_dump_period_sec = 0;
-  options.stats_persist_period_sec = 0;
  options.env = env_;

  int64_t rate_bytes_per_sec = 1024 * 10;  // 10 Kbs / Sec
@@ -1421,7 +1421,7 @@ TEST_F(DBTest, ApproximateSizesMemTable) {
    keys[i * 3 + 1] = i * 5 + 1;
    keys[i * 3 + 2] = i * 5 + 2;
  }
-  std::random_shuffle(std::begin(keys), std::end(keys));
+  RandomShuffle(std::begin(keys), std::end(keys));

  for (int i = 0; i < N * 3; i++) {
    ASSERT_OK(Put(Key(keys[i] + 1000), RandomString(&rnd, 1024)));
@@ -2309,6 +2309,42 @@ TEST_F(DBTest, ReadonlyDBGetLiveManifestSize) {
    Close();
  } while (ChangeCompactOptions());
 }
+
+TEST_F(DBTest, GetLiveBlobFiles) {
+  VersionSet* const versions = dbfull()->TEST_GetVersionSet();
+  assert(versions);
+  assert(versions->GetColumnFamilySet());
+
+  ColumnFamilyData* const cfd = versions->GetColumnFamilySet()->GetDefault();
+  assert(cfd);
+
+  // Add a live blob file.
+  VersionEdit edit;
+
+  constexpr uint64_t blob_file_number = 234;
+  constexpr uint64_t total_blob_count = 555;
+  constexpr uint64_t total_blob_bytes = 66666;
+  constexpr char checksum_method[] = "CRC32";
+  constexpr char checksum_value[] = "3d87ff57";
+
+  edit.AddBlobFile(blob_file_number, total_blob_count, total_blob_bytes,
+                   checksum_method, checksum_value);
+
+  dbfull()->TEST_LockMutex();
+  Status s = versions->LogAndApply(cfd, *cfd->GetLatestMutableCFOptions(),
+                                   &edit, dbfull()->mutex());
+  dbfull()->TEST_UnlockMutex();
+
+  ASSERT_OK(s);
+
+  // Make sure it appears in the results returned by GetLiveFiles.
+  uint64_t manifest_size = 0;
+  std::vector<std::string> files;
+  ASSERT_OK(dbfull()->GetLiveFiles(files, &manifest_size));
+
+  ASSERT_FALSE(files.empty());
+  ASSERT_EQ(files[0], BlobFileName("", blob_file_number));
+}
 #endif

 TEST_F(DBTest, PurgeInfoLogs) {
@@ -4530,7 +4566,7 @@ TEST_F(DBTest, DynamicLevelCompressionPerLevel) {
  for (int i = 0; i < kNKeys; i++) {
    keys[i] = i;
  }
-  std::random_shuffle(std::begin(keys), std::end(keys));
+  RandomShuffle(std::begin(keys), std::end(keys));

  Random rnd(301);
  Options options;
@@ -4613,7 +4649,7 @@ TEST_F(DBTest, DynamicLevelCompressionPerLevel2) {
  for (int i = 0; i < kNKeys; i++) {
    keys[i] = i;
  }
-  std::random_shuffle(std::begin(keys), std::end(keys));
+  RandomShuffle(std::begin(keys), std::end(keys));

  Random rnd(301);
  Options options;
@@ -1288,6 +1288,10 @@ TEST_F(DBTest2, CompressionOptions) {
  const int kValSize = 20;
  Random rnd(301);

+  std::vector<uint32_t> compression_parallel_threads = {1, 4};
+
+  std::map<std::string, std::string> key_value_written;
+
  for (int iter = 0; iter <= 2; iter++) {
    listener->max_level_checked = 0;

@@ -1312,19 +1316,37 @@ TEST_F(DBTest2, CompressionOptions) {
      options.bottommost_compression = kDisableCompressionOption;
    }

-    DestroyAndReopen(options);
-    // Write 10 random files
-    for (int i = 0; i < 10; i++) {
-      for (int j = 0; j < 5; j++) {
-        ASSERT_OK(
-            Put(RandomString(&rnd, kKeySize), RandomString(&rnd, kValSize)));
-      }
-      ASSERT_OK(Flush());
-      dbfull()->TEST_WaitForCompact();
-    }
+    for (auto num_threads : compression_parallel_threads) {
+      options.compression_opts.parallel_threads = num_threads;
+      options.bottommost_compression_opts.parallel_threads = num_threads;

-    // Make sure that we wrote enough to check all 7 levels
-    ASSERT_EQ(listener->max_level_checked, 6);
+      DestroyAndReopen(options);
+      // Write 10 random files
+      for (int i = 0; i < 10; i++) {
+        for (int j = 0; j < 5; j++) {
+          std::string key = RandomString(&rnd, kKeySize);
+          std::string value = RandomString(&rnd, kValSize);
+          key_value_written[key] = value;
+          ASSERT_OK(Put(key, value));
+        }
+        ASSERT_OK(Flush());
+        dbfull()->TEST_WaitForCompact();
+      }
+
+      // Make sure that we wrote enough to check all 7 levels
+      ASSERT_EQ(listener->max_level_checked, 6);
+
+      // Make sure database content is the same as key_value_written
+      std::unique_ptr<Iterator> db_iter(db_->NewIterator(ReadOptions()));
+      for (db_iter->SeekToFirst(); db_iter->Valid(); db_iter->Next()) {
+        std::string key = db_iter->key().ToString();
+        std::string value = db_iter->value().ToString();
+        ASSERT_NE(key_value_written.find(key), key_value_written.end());
+        ASSERT_EQ(key_value_written[key], value);
+        key_value_written.erase(key);
+      }
+      ASSERT_EQ(0, key_value_written.size());
+    }
  }
 }

@@ -4306,6 +4328,24 @@ TEST_F(DBTest2, SameSmallestInSameLevel) {
  ASSERT_EQ("2,3,4,5,6,7,8", Get("key"));
 }

+TEST_F(DBTest2, FileConsistencyCheckInOpen) {
+  Put("foo", "bar");
+  Flush();
+
+  SyncPoint::GetInstance()->SetCallBack(
+      "VersionBuilder::CheckConsistencyBeforeReturn", [&](void* arg) {
+        Status* ret_s = static_cast<Status*>(arg);
+        *ret_s = Status::Corruption("fcc");
+      });
+  SyncPoint::GetInstance()->EnableProcessing();
+
+  Options options = CurrentOptions();
+  options.force_consistency_checks = true;
+  ASSERT_NOK(TryReopen(options));
+
+  SyncPoint::GetInstance()->DisableProcessing();
+}
+
 TEST_F(DBTest2, BlockBasedTablePrefixIndexSeekForPrev) {
  // create a DB with block prefix index
  BlockBasedTableOptions table_options;
@@ -14,10 +14,19 @@

 namespace ROCKSDB_NAMESPACE {

+namespace {
+int64_t MaybeCurrentTime(Env* env) {
+  int64_t time = 1337346000;  // arbitrary fallback default
+  (void)env->GetCurrentTime(&time);
+  return time;
+}
+}  // namespace
+
 // Special Env used to delay background operations

 SpecialEnv::SpecialEnv(Env* base)
    : EnvWrapper(base),
+      maybe_starting_time_(MaybeCurrentTime(base)),
      rnd_(301),
      sleep_counter_(this),
      addon_time_(0),
@@ -399,20 +408,7 @@ Options DBTestBase::GetOptions(
        options.use_direct_reads = true;
        options.use_direct_io_for_flush_and_compaction = true;
        options.compaction_readahead_size = 2 * 1024 * 1024;
-  #if !defined(OS_MACOSX) && !defined(OS_WIN) && !defined(OS_SOLARIS) && \
-      !defined(OS_AIX) && !defined(OS_OPENBSD)
-        ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->SetCallBack(
-            "NewWritableFile:O_DIRECT", [&](void* arg) {
-              int* val = static_cast<int*>(arg);
-              *val &= ~O_DIRECT;
-            });
-        ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->SetCallBack(
-            "NewRandomAccessFile:O_DIRECT", [&](void* arg) {
-              int* val = static_cast<int*>(arg);
-              *val &= ~O_DIRECT;
-            });
-        ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->EnableProcessing();
-#endif
+        test::SetupSyncPointsToMockDirectIO();
        break;
      }
 #endif  // ROCKSDB_LITE
@@ -502,10 +502,14 @@ class SpecialEnv : public EnvWrapper {

  virtual Status GetCurrentTime(int64_t* unix_time) override {
    Status s;
-    if (!time_elapse_only_sleep_) {
+    if (time_elapse_only_sleep_) {
+      *unix_time = maybe_starting_time_;
+    } else {
      s = target()->GetCurrentTime(unix_time);
    }
    if (s.ok()) {
+      // FIXME: addon_time_ sometimes used to mean seconds (here) and
+      // sometimes microseconds
      *unix_time += addon_time_.load();
    }
    return s;
@@ -531,6 +535,20 @@ class SpecialEnv : public EnvWrapper {
    return target()->DeleteFile(fname);
  }

+  void SetTimeElapseOnlySleep(Options* options) {
+    time_elapse_only_sleep_ = true;
+    no_slowdown_ = true;
+    // Need to disable stats dumping and persisting which also use
+    // RepeatableThread, which uses InstrumentedCondVar::TimedWaitInternal.
+    // With time_elapse_only_sleep_, this can hang on some platforms.
+    // TODO: why? investigate/fix
+    options->stats_dump_period_sec = 0;
+    options->stats_persist_period_sec = 0;
+  }
+
+  // Something to return when mocking current time
+  const int64_t maybe_starting_time_;
+
  Random rnd_;
  port::Mutex rnd_mutex_;  // Lock to pretect rnd_

@@ -647,6 +665,72 @@ class TestPutOperator : public MergeOperator {
  virtual const char* Name() const override { return "TestPutOperator"; }
 };

+// A wrapper around Cache that can easily be extended with instrumentation,
+// etc.
+class CacheWrapper : public Cache {
+ public:
+  explicit CacheWrapper(std::shared_ptr<Cache> target)
+      : target_(std::move(target)) {}
+
+  const char* Name() const override { return target_->Name(); }
+
+  Status Insert(const Slice& key, void* value, size_t charge,
+                void (*deleter)(const Slice& key, void* value),
+                Handle** handle = nullptr,
+                Priority priority = Priority::LOW) override {
+    return target_->Insert(key, value, charge, deleter, handle, priority);
+  }
+
+  Handle* Lookup(const Slice& key, Statistics* stats = nullptr) override {
+    return target_->Lookup(key, stats);
+  }
+
+  bool Ref(Handle* handle) override { return target_->Ref(handle); }
+
+  bool Release(Handle* handle, bool force_erase = false) override {
+    return target_->Release(handle, force_erase);
+  }
+
+  void* Value(Handle* handle) override { return target_->Value(handle); }
+
+  void Erase(const Slice& key) override { target_->Erase(key); }
+  uint64_t NewId() override { return target_->NewId(); }
+
+  void SetCapacity(size_t capacity) override { target_->SetCapacity(capacity); }
+
+  void SetStrictCapacityLimit(bool strict_capacity_limit) override {
+    target_->SetStrictCapacityLimit(strict_capacity_limit);
+  }
+
+  bool HasStrictCapacityLimit() const override {
+    return target_->HasStrictCapacityLimit();
+  }
+
+  size_t GetCapacity() const override { return target_->GetCapacity(); }
+
+  size_t GetUsage() const override { return target_->GetUsage(); }
+
+  size_t GetUsage(Handle* handle) const override {
+    return target_->GetUsage(handle);
+  }
+
+  size_t GetPinnedUsage() const override { return target_->GetPinnedUsage(); }
+
+  size_t GetCharge(Handle* handle) const override {
+    return target_->GetCharge(handle);
+  }
+
+  void ApplyToAllCacheEntries(void (*callback)(void*, size_t),
+                              bool thread_safe) override {
+    target_->ApplyToAllCacheEntries(callback, thread_safe);
+  }
+
+  void EraseUnRefEntries() override { target_->EraseUnRefEntries(); }
+
+ protected:
+  std::shared_ptr<Cache> target_;
+};
+
 class DBTestBase : public testing::Test {
 public:
  // Sequence of option configurations to try
@@ -1422,8 +1422,11 @@ TEST_F(DBWALTest, RecoverFromCorruptedWALWithoutFlush) {
    delete iter;
    return data;
  };
-  for (auto& mode : wal_recovery_mode_string_map) {
-    options.wal_recovery_mode = mode.second;
+  for (auto& mode : {WALRecoveryMode::kTolerateCorruptedTailRecords,
+                     WALRecoveryMode::kAbsoluteConsistency,
+                     WALRecoveryMode::kPointInTimeRecovery,
+                     WALRecoveryMode::kSkipAnyCorruptedRecords}) {
+    options.wal_recovery_mode = mode;
    for (auto trunc : {true, false}) {
      for (int i = 0; i < 4; i++) {
        for (int j = jstart; j < jend; j++) {
@@ -26,22 +26,8 @@ class DBBasicTestWithTimestampBase : public DBTestBase {

 protected:
  static std::string Key1(uint64_t k) {
-    uint32_t x = 1;
-    const bool is_little_endian = (*reinterpret_cast<char*>(&x) != 0);
    std::string ret;
-    if (is_little_endian) {
-      ret.assign(reinterpret_cast<char*>(&k), sizeof(k));
-    } else {
-      ret.resize(sizeof(k));
-      ret[0] = k & 0xff;
-      ret[1] = (k >> 8) & 0xff;
-      ret[2] = (k >> 16) & 0xff;
-      ret[3] = (k >> 24) & 0xff;
-      ret[4] = (k >> 32) & 0xff;
-      ret[5] = (k >> 40) & 0xff;
-      ret[6] = (k >> 48) & 0xff;
-      ret[7] = (k >> 56) & 0xff;
-    }
+    PutFixed64(&ret, k);
    std::reverse(ret.begin(), ret.end());
    return ret;
  }
@@ -173,8 +159,6 @@ TEST_F(DBBasicTestWithTimestamp, SimpleForwardIterate) {
  const uint64_t kMaxKey = 1024;
  Options options = CurrentOptions();
  options.env = env_;
-  // TODO(yanqin) re-enable auto compaction
-  options.disable_auto_compactions = true;
  options.create_if_missing = true;
  const size_t kTimestampSize = Timestamp(0, 0).size();
  TestComparator test_cmp(kTimestampSize);
@@ -235,6 +219,56 @@ TEST_F(DBBasicTestWithTimestamp, SimpleForwardIterate) {
  Close();
 }

+TEST_F(DBBasicTestWithTimestamp, SimpleForwardIterateLowerTsBound) {
+  const int kNumKeysPerFile = 128;
+  const uint64_t kMaxKey = 1024;
+  Options options = CurrentOptions();
+  options.env = env_;
+  options.create_if_missing = true;
+  const size_t kTimestampSize = Timestamp(0, 0).size();
+  TestComparator test_cmp(kTimestampSize);
+  options.comparator = &test_cmp;
+  options.memtable_factory.reset(new SpecialSkipListFactory(kNumKeysPerFile));
+  DestroyAndReopen(options);
+  const std::vector<std::string> write_timestamps = {Timestamp(1, 0),
+                                                     Timestamp(3, 0)};
+  const std::vector<std::string> read_timestamps = {Timestamp(2, 0),
+                                                    Timestamp(4, 0)};
+  const std::vector<std::string> read_timestamps_lb = {Timestamp(1, 0),
+                                                       Timestamp(1, 0)};
+  for (size_t i = 0; i < write_timestamps.size(); ++i) {
+    WriteOptions write_opts;
+    Slice write_ts = write_timestamps[i];
+    write_opts.timestamp = &write_ts;
+    for (uint64_t key = 0; key <= kMaxKey; ++key) {
+      Status s = db_->Put(write_opts, Key1(key), "value" + std::to_string(i));
+      ASSERT_OK(s);
+    }
+  }
+  for (size_t i = 0; i < read_timestamps.size(); ++i) {
+    ReadOptions read_opts;
+    Slice read_ts = read_timestamps[i];
+    Slice read_ts_lb = read_timestamps_lb[i];
+    read_opts.timestamp = &read_ts;
+    read_opts.iter_start_ts = &read_ts_lb;
+    std::unique_ptr<Iterator> it(db_->NewIterator(read_opts));
+    int count = 0;
+    uint64_t key = 0;
+    for (it->Seek(Key1(0)), key = 0; it->Valid(); it->Next(), ++count, ++key) {
+      CheckIterUserEntry(it.get(), Key1(key), "value" + std::to_string(i),
+                         write_timestamps[i]);
+      if (i > 0) {
+        it->Next();
+        CheckIterUserEntry(it.get(), Key1(key), "value" + std::to_string(i - 1),
+                           write_timestamps[i - 1]);
+      }
+    }
+    size_t expected_count = kMaxKey + 1;
+    ASSERT_EQ(expected_count, count);
+  }
+  Close();
+}
+
 TEST_F(DBBasicTestWithTimestamp, ForwardIterateStartSeqnum) {
  const int kNumKeysPerFile = 128;
  const uint64_t kMaxKey = 0xffffffffffffffff;
@@ -242,7 +276,9 @@ TEST_F(DBBasicTestWithTimestamp, ForwardIterateStartSeqnum) {
  Options options = CurrentOptions();
  options.env = env_;
  options.create_if_missing = true;
-  // TODO(yanqin) re-enable auto compaction
+  // Need to disable compaction to bottommost level when sequence number will be
+  // zeroed out, causing the verification of sequence number to fail in this
+  // test.
  options.disable_auto_compactions = true;
  const size_t kTimestampSize = Timestamp(0, 0).size();
  TestComparator test_cmp(kTimestampSize);
@@ -300,8 +336,6 @@ TEST_F(DBBasicTestWithTimestamp, ReseekToTargetTimestamp) {
  constexpr size_t kNumKeys = 16;
  options.max_sequential_skip_in_iterations = kNumKeys / 2;
  options.statistics = ROCKSDB_NAMESPACE::CreateDBStatistics();
-  // TODO(yanqin) re-enable auto compaction
-  options.disable_auto_compactions = true;
  const size_t kTimestampSize = Timestamp(0, 0).size();
  TestComparator test_cmp(kTimestampSize);
  options.comparator = &test_cmp;
@@ -337,8 +371,6 @@ TEST_F(DBBasicTestWithTimestamp, ReseekToNextUserKey) {
  constexpr size_t kNumKeys = 16;
  options.max_sequential_skip_in_iterations = kNumKeys / 2;
  options.statistics = ROCKSDB_NAMESPACE::CreateDBStatistics();
-  // TODO(yanqin) re-enable auto compaction
-  options.disable_auto_compactions = true;
  const size_t kTimestampSize = Timestamp(0, 0).size();
  TestComparator test_cmp(kTimestampSize);
  options.comparator = &test_cmp;
@@ -419,8 +451,9 @@ TEST_F(DBBasicTestWithTimestamp, MaxKeysSkipped) {

 class DBBasicTestWithTimestampCompressionSettings
    : public DBBasicTestWithTimestampBase,
-      public testing::WithParamInterface<std::tuple<
-          std::shared_ptr<const FilterPolicy>, CompressionType, uint32_t>> {
+      public testing::WithParamInterface<
+          std::tuple<std::shared_ptr<const FilterPolicy>, CompressionType,
+                     uint32_t, uint32_t>> {
 public:
  DBBasicTestWithTimestampCompressionSettings()
      : DBBasicTestWithTimestampBase(
@@ -460,6 +493,7 @@ TEST_P(DBBasicTestWithTimestampCompressionSettings, PutAndGet) {
  if (comp_type == kZSTD) {
    options.compression_opts.zstd_max_train_bytes = std::get<2>(GetParam());
  }
+  options.compression_opts.parallel_threads = std::get<3>(GetParam());
  options.target_file_size_base = 1 << 26;  // 64MB
  DestroyAndReopen(options);
  CreateAndReopenWithCF({"pikachu"}, options);
@@ -572,6 +606,7 @@ TEST_P(DBBasicTestWithTimestampCompressionSettings, PutAndGetWithCompaction) {
  if (comp_type == kZSTD) {
    options.compression_opts.zstd_max_train_bytes = std::get<2>(GetParam());
  }
+  options.compression_opts.parallel_threads = std::get<3>(GetParam());
  DestroyAndReopen(options);
  CreateAndReopenWithCF({"pikachu"}, options);

@@ -581,7 +616,7 @@ TEST_P(DBBasicTestWithTimestampCompressionSettings, PutAndGetWithCompaction) {
  std::vector<std::string> read_ts_list;

  const auto& verify_records_func = [&](size_t i, size_t begin, size_t end,
-                                       ColumnFamilyHandle* cfh) {
+                                        ColumnFamilyHandle* cfh) {
    std::string value;
    std::string timestamp;

@@ -619,9 +654,9 @@ TEST_P(DBBasicTestWithTimestampCompressionSettings, PutAndGetWithCompaction) {
          // higherlevel[0].largest.userkey
          ASSERT_OK(Flush(cf));

-          // compact files (2 at each level) to a lower level such that all keys
-          // with the same timestamp is at one level, with newer versions at
-          // higher levels.
+          // compact files (2 at each level) to a lower level such that all
+          // keys with the same timestamp is at one level, with newer versions
+          // at higher levels.
          CompactionOptions compact_opt;
          compact_opt.compression = kNoCompression;
          db_->CompactFiles(compact_opt, handles_[cf],
@@ -739,6 +774,55 @@ TEST_F(DBBasicTestWithTimestamp, BatchWriteAndMultiGet) {
  Close();
 }

+TEST_F(DBBasicTestWithTimestamp, MultiGetNoReturnTs) {
+  Options options = CurrentOptions();
+  options.env = env_;
+  const size_t kTimestampSize = Timestamp(0, 0).size();
+  TestComparator test_cmp(kTimestampSize);
+  options.comparator = &test_cmp;
+  DestroyAndReopen(options);
+  WriteOptions write_opts;
+  std::string ts_str = Timestamp(1, 0);
+  Slice ts = ts_str;
+  write_opts.timestamp = &ts;
+  ASSERT_OK(db_->Put(write_opts, "foo", "value"));
+  ASSERT_OK(db_->Put(write_opts, "bar", "value"));
+  ASSERT_OK(db_->Put(write_opts, "fooxxxxxxxxxxxxxxxx", "value"));
+  ASSERT_OK(db_->Put(write_opts, "barxxxxxxxxxxxxxxxx", "value"));
+  ColumnFamilyHandle* cfh = dbfull()->DefaultColumnFamily();
+  ts_str = Timestamp(2, 0);
+  ts = ts_str;
+  ReadOptions read_opts;
+  read_opts.timestamp = &ts;
+  {
+    ColumnFamilyHandle* column_families[] = {cfh, cfh};
+    Slice keys[] = {"foo", "bar"};
+    PinnableSlice values[] = {PinnableSlice(), PinnableSlice()};
+    Status statuses[] = {Status::OK(), Status::OK()};
+    dbfull()->MultiGet(read_opts, /*num_keys=*/2, &column_families[0], &keys[0],
+                       &values[0], &statuses[0], /*sorted_input=*/false);
+    for (const auto& s : statuses) {
+      ASSERT_OK(s);
+    }
+  }
+  {
+    ColumnFamilyHandle* column_families[] = {cfh, cfh, cfh, cfh};
+    // Make user keys longer than configured timestamp size (16 bytes) to
+    // verify RocksDB does not use the trailing bytes 'x' as timestamp.
+    Slice keys[] = {"fooxxxxxxxxxxxxxxxx", "barxxxxxxxxxxxxxxxx", "foo", "bar"};
+    PinnableSlice values[] = {PinnableSlice(), PinnableSlice(), PinnableSlice(),
+                              PinnableSlice()};
+    Status statuses[] = {Status::OK(), Status::OK(), Status::OK(),
+                         Status::OK()};
+    dbfull()->MultiGet(read_opts, /*num_keys=*/4, &column_families[0], &keys[0],
+                       &values[0], &statuses[0], /*sorted_input=*/false);
+    for (const auto& s : statuses) {
+      ASSERT_OK(s);
+    }
+  }
+  Close();
+}
+
 #endif  // !ROCKSDB_LITE

 INSTANTIATE_TEST_CASE_P(
@@ -749,7 +833,7 @@ INSTANTIATE_TEST_CASE_P(
                              NewBloomFilterPolicy(10, false))),
        ::testing::Values(kNoCompression, kZlibCompression, kLZ4Compression,
                          kLZ4HCCompression, kZSTD),
-        ::testing::Values(0, 1 << 14)));
+        ::testing::Values(0, 1 << 14), ::testing::Values(1, 4)));

 class DBBasicTestWithTimestampPrefixSeek
    : public DBBasicTestWithTimestampBase,
@@ -767,8 +851,6 @@ TEST_P(DBBasicTestWithTimestampPrefixSeek, ForwardIterateWithPrefix) {
  Options options = CurrentOptions();
  options.env = env_;
  options.create_if_missing = true;
-  // TODO(yanqin): re-enable auto compactions
-  options.disable_auto_compactions = true;
  const size_t kTimestampSize = Timestamp(0, 0).size();
  TestComparator test_cmp(kTimestampSize);
  options.comparator = &test_cmp;
@@ -0,0 +1,119 @@
+//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root 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/compaction/compaction.h"
+#include "db/db_test_util.h"
+#include "port/stack_trace.h"
+
+namespace ROCKSDB_NAMESPACE {
+
+namespace {
+std::string Key1(uint64_t key) {
+  std::string ret;
+  PutFixed64(&ret, key);
+  std::reverse(ret.begin(), ret.end());
+  return ret;
+}
+
+std::string Timestamp(uint64_t ts) {
+  std::string ret;
+  PutFixed64(&ret, ts);
+  return ret;
+}
+}  // anonymous namespace
+
+class TimestampCompatibleCompactionTest : public DBTestBase {
+ public:
+  TimestampCompatibleCompactionTest()
+      : DBTestBase("/ts_compatible_compaction_test") {}
+
+  std::string Get(const std::string& key, uint64_t ts) {
+    ReadOptions read_opts;
+    std::string ts_str = Timestamp(ts);
+    Slice ts_slice = ts_str;
+    read_opts.timestamp = &ts_slice;
+    std::string value;
+    Status s = db_->Get(read_opts, key, &value);
+    if (s.IsNotFound()) {
+      value.assign("NOT_FOUND");
+    } else if (!s.ok()) {
+      value.assign(s.ToString());
+    }
+    return value;
+  }
+};
+
+TEST_F(TimestampCompatibleCompactionTest, UserKeyCrossFileBoundary) {
+  Options options = CurrentOptions();
+  options.env = env_;
+  options.compaction_style = kCompactionStyleLevel;
+  options.comparator = test::ComparatorWithU64Ts();
+  options.level0_file_num_compaction_trigger = 3;
+  constexpr size_t kNumKeysPerFile = 101;
+  options.memtable_factory.reset(new SpecialSkipListFactory(kNumKeysPerFile));
+  DestroyAndReopen(options);
+  SyncPoint::GetInstance()->DisableProcessing();
+  SyncPoint::GetInstance()->ClearAllCallBacks();
+  SyncPoint::GetInstance()->SetCallBack(
+      "LevelCompactionPicker::PickCompaction:Return", [&](void* arg) {
+        const auto* compaction = reinterpret_cast<Compaction*>(arg);
+        ASSERT_NE(nullptr, compaction);
+        ASSERT_EQ(0, compaction->start_level());
+        ASSERT_EQ(1, compaction->num_input_levels());
+        // Check that all 3 L0 ssts are picked for level compaction.
+        ASSERT_EQ(3, compaction->num_input_files(0));
+      });
+  SyncPoint::GetInstance()->EnableProcessing();
+  // Write a L0 with keys 0, 1, ..., 99 with ts from 100 to 199.
+  uint64_t ts = 100;
+  uint64_t key = 0;
+  WriteOptions write_opts;
+  for (; key < kNumKeysPerFile - 1; ++key, ++ts) {
+    std::string ts_str = Timestamp(ts);
+    Slice ts_slice = ts_str;
+    write_opts.timestamp = &ts_slice;
+    ASSERT_OK(db_->Put(write_opts, Key1(key), "foo_" + std::to_string(key)));
+  }
+  // Write another L0 with keys 99 with newer ts.
+  ASSERT_OK(Flush());
+  uint64_t saved_read_ts1 = ts++;
+  key = 99;
+  for (int i = 0; i < 4; ++i, ++ts) {
+    std::string ts_str = Timestamp(ts);
+    Slice ts_slice = ts_str;
+    write_opts.timestamp = &ts_slice;
+    ASSERT_OK(db_->Put(write_opts, Key1(key), "bar_" + std::to_string(key)));
+  }
+  ASSERT_OK(Flush());
+  uint64_t saved_read_ts2 = ts++;
+  // Write another L0 with keys 99, 100, 101, ..., 150
+  for (; key <= 150; ++key, ++ts) {
+    std::string ts_str = Timestamp(ts);
+    Slice ts_slice = ts_str;
+    write_opts.timestamp = &ts_slice;
+    ASSERT_OK(db_->Put(write_opts, Key1(key), "foo1_" + std::to_string(key)));
+  }
+  ASSERT_OK(Flush());
+  // Wait for compaction to finish
+  ASSERT_OK(dbfull()->TEST_WaitForCompact());
+  uint64_t read_ts = ts;
+  ASSERT_EQ("foo_99", Get(Key1(99), saved_read_ts1));
+  ASSERT_EQ("bar_99", Get(Key1(99), saved_read_ts2));
+  ASSERT_EQ("foo1_99", Get(Key1(99), read_ts));
+  SyncPoint::GetInstance()->ClearAllCallBacks();
+  SyncPoint::GetInstance()->DisableProcessing();
+}
+
+}  // namespace ROCKSDB_NAMESPACE
+
+int main(int argc, char** argv) {
+  ROCKSDB_NAMESPACE::port::InstallStackTraceHandler();
+  ::testing::InitGoogleTest(&argc, argv);
+  return RUN_ALL_TESTS();
+}
@@ -498,15 +498,15 @@ TEST_F(DBErrorHandlingFSTest, CompactionManifestWriteRetryableError) {
  ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->SetCallBack(
      "VersionSet::LogAndApply:WriteManifest", [&](void*) {
        if (fail_manifest.load()) {
-          fault_fs->SetFilesystemActive(false,error_msg); }
-        });
+          fault_fs->SetFilesystemActive(false, error_msg);
+        }
+      });
  ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->EnableProcessing();

  Put(Key(1), "val");
  s = Flush();
  ASSERT_EQ(s, Status::OK());

-
  TEST_SYNC_POINT("CompactionManifestWriteError:0");
  TEST_SYNC_POINT("CompactionManifestWriteError:1");

@@ -181,8 +181,8 @@ TEST_F(FlushJobTest, NonEmpty) {
  // Note: the first two blob references will not be considered when resolving
  // the oldest blob file referenced (the first one is inlined TTL, while the
  // second one is TTL and thus points to a TTL blob file).
-  constexpr std::array<uint64_t, 6> blob_file_numbers{
-      kInvalidBlobFileNumber, 5, 103, 17, 102, 101};
+  constexpr std::array<uint64_t, 6> blob_file_numbers{{
+      kInvalidBlobFileNumber, 5, 103, 17, 102, 101}};
  for (size_t i = 0; i < blob_file_numbers.size(); ++i) {
    std::string key(ToString(i + 10001));
    std::string blob_index;
@@ -36,7 +36,8 @@ class ForwardLevelIterator : public InternalIterator {
  ForwardLevelIterator(const ColumnFamilyData* const cfd,
                       const ReadOptions& read_options,
                       const std::vector<FileMetaData*>& files,
-                       const SliceTransform* prefix_extractor)
+                       const SliceTransform* prefix_extractor,
+                       bool allow_unprepared_value)
      : cfd_(cfd),
        read_options_(read_options),
        files_(files),
@@ -44,7 +45,8 @@ class ForwardLevelIterator : public InternalIterator {
        file_index_(std::numeric_limits<uint32_t>::max()),
        file_iter_(nullptr),
        pinned_iters_mgr_(nullptr),
-        prefix_extractor_(prefix_extractor) {}
+        prefix_extractor_(prefix_extractor),
+        allow_unprepared_value_(allow_unprepared_value) {}

  ~ForwardLevelIterator() override {
    // Reset current pointer
@@ -83,7 +85,8 @@ class ForwardLevelIterator : public InternalIterator {
        /*file_read_hist=*/nullptr, TableReaderCaller::kUserIterator,
        /*arena=*/nullptr, /*skip_filters=*/false, /*level=*/-1,
        /*smallest_compaction_key=*/nullptr,
-        /*largest_compaction_key=*/nullptr);
+        /*largest_compaction_key=*/nullptr,
+        allow_unprepared_value_);
    file_iter_->SetPinnedItersMgr(pinned_iters_mgr_);
    valid_ = false;
    if (!range_del_agg.IsEmpty()) {
@@ -171,6 +174,16 @@ class ForwardLevelIterator : public InternalIterator {
    }
    return Status::OK();
  }
+  bool PrepareValue() override {
+    assert(valid_);
+    if (file_iter_->PrepareValue()) {
+      return true;
+    }
+
+    assert(!file_iter_->Valid());
+    valid_ = false;
+    return false;
+  }
  bool IsKeyPinned() const override {
    return pinned_iters_mgr_ && pinned_iters_mgr_->PinningEnabled() &&
           file_iter_->IsKeyPinned();
@@ -197,16 +210,19 @@ class ForwardLevelIterator : public InternalIterator {
  InternalIterator* file_iter_;
  PinnedIteratorsManager* pinned_iters_mgr_;
  const SliceTransform* prefix_extractor_;
+  const bool allow_unprepared_value_;
 };

 ForwardIterator::ForwardIterator(DBImpl* db, const ReadOptions& read_options,
                                 ColumnFamilyData* cfd,
-                                 SuperVersion* current_sv)
+                                 SuperVersion* current_sv,
+                                 bool allow_unprepared_value)
    : db_(db),
      read_options_(read_options),
      cfd_(cfd),
      prefix_extractor_(current_sv->mutable_cf_options.prefix_extractor.get()),
      user_comparator_(cfd->user_comparator()),
+      allow_unprepared_value_(allow_unprepared_value),
      immutable_min_heap_(MinIterComparator(&cfd_->internal_comparator())),
      sv_(current_sv),
      mutable_iter_(nullptr),
@@ -560,6 +576,22 @@ Status ForwardIterator::status() const {
  return immutable_status_;
 }

+bool ForwardIterator::PrepareValue() {
+  assert(valid_);
+  if (current_->PrepareValue()) {
+    return true;
+  }
+
+  assert(!current_->Valid());
+  assert(!current_->status().ok());
+  assert(current_ != mutable_iter_); // memtable iterator can't fail
+  assert(immutable_status_.ok());
+
+  valid_ = false;
+  immutable_status_ = current_->status();
+  return false;
+}
+
 Status ForwardIterator::GetProperty(std::string prop_name, std::string* prop) {
  assert(prop != nullptr);
  if (prop_name == "rocksdb.iterator.super-version-number") {
@@ -655,7 +687,8 @@ void ForwardIterator::RebuildIterators(bool refresh_sv) {
        TableReaderCaller::kUserIterator, /*arena=*/nullptr,
        /*skip_filters=*/false, /*level=*/-1,
        /*smallest_compaction_key=*/nullptr,
-        /*largest_compaction_key=*/nullptr));
+        /*largest_compaction_key=*/nullptr,
+        allow_unprepared_value_));
  }
  BuildLevelIterators(vstorage);
  current_ = nullptr;
@@ -732,7 +765,8 @@ void ForwardIterator::RenewIterators() {
        TableReaderCaller::kUserIterator, /*arena=*/nullptr,
        /*skip_filters=*/false, /*level=*/-1,
        /*smallest_compaction_key=*/nullptr,
-        /*largest_compaction_key=*/nullptr));
+        /*largest_compaction_key=*/nullptr,
+        allow_unprepared_value_));
  }

  for (auto* f : l0_iters_) {
@@ -775,7 +809,8 @@ void ForwardIterator::BuildLevelIterators(const VersionStorageInfo* vstorage) {
    } else {
      level_iters_.push_back(new ForwardLevelIterator(
          cfd_, read_options_, level_files,
-          sv_->mutable_cf_options.prefix_extractor.get()));
+          sv_->mutable_cf_options.prefix_extractor.get(),
+          allow_unprepared_value_));
    }
  }
 }
@@ -796,7 +831,8 @@ void ForwardIterator::ResetIncompleteIterators() {
        TableReaderCaller::kUserIterator, /*arena=*/nullptr,
        /*skip_filters=*/false, /*level=*/-1,
        /*smallest_compaction_key=*/nullptr,
-        /*largest_compaction_key=*/nullptr);
+        /*largest_compaction_key=*/nullptr,
+        allow_unprepared_value_);
    l0_iters_[i]->SetPinnedItersMgr(pinned_iters_mgr_);
  }

@@ -52,7 +52,8 @@ typedef std::priority_queue<InternalIterator*, std::vector<InternalIterator*>,
 class ForwardIterator : public InternalIterator {
 public:
  ForwardIterator(DBImpl* db, const ReadOptions& read_options,
-                  ColumnFamilyData* cfd, SuperVersion* current_sv = nullptr);
+                  ColumnFamilyData* cfd, SuperVersion* current_sv = nullptr,
+                  bool allow_unprepared_value = false);
  virtual ~ForwardIterator();

  void SeekForPrev(const Slice& /*target*/) override {
@@ -75,6 +76,7 @@ class ForwardIterator : public InternalIterator {
  virtual Slice key() const override;
  virtual Slice value() const override;
  virtual Status status() const override;
+  virtual bool PrepareValue() override;
  virtual Status GetProperty(std::string prop_name, std::string* prop) override;
  virtual void SetPinnedItersMgr(
      PinnedIteratorsManager* pinned_iters_mgr) override;
@@ -120,6 +122,7 @@ class ForwardIterator : public InternalIterator {
  ColumnFamilyData* const cfd_;
  const SliceTransform* const prefix_extractor_;
  const Comparator* user_comparator_;
+  const bool allow_unprepared_value_;
  MinIterHeap immutable_min_heap_;

  SuperVersion* sv_;
@@ -33,7 +33,6 @@ Status ImportColumnFamilyJob::Prepare(uint64_t next_file_number,
    files_to_import_.push_back(file_to_import);
  }

-  const auto ucmp = cfd_->internal_comparator().user_comparator();
  auto num_files = files_to_import_.size();
  if (num_files == 0) {
    return Status::InvalidArgument("The list of files is empty");
@@ -55,17 +54,18 @@ Status ImportColumnFamilyJob::Prepare(uint64_t next_file_number,
        }
      }

-      std::sort(sorted_files.begin(), sorted_files.end(),
-                [&ucmp](const IngestedFileInfo* info1,
-                        const IngestedFileInfo* info2) {
-                  return sstableKeyCompare(ucmp, info1->smallest_internal_key,
-                                           info2->smallest_internal_key) < 0;
-                });
+      std::sort(
+          sorted_files.begin(), sorted_files.end(),
+          [this](const IngestedFileInfo* info1, const IngestedFileInfo* info2) {
+            return cfd_->internal_comparator().Compare(
+                       info1->smallest_internal_key,
+                       info2->smallest_internal_key) < 0;
+          });

-      for (size_t i = 0; i < sorted_files.size() - 1; i++) {
-        if (sstableKeyCompare(ucmp, sorted_files[i]->largest_internal_key,
-                              sorted_files[i + 1]->smallest_internal_key) >=
-            0) {
+      for (size_t i = 0; i + 1 < sorted_files.size(); i++) {
+        if (cfd_->internal_comparator().Compare(
+                sorted_files[i]->largest_internal_key,
+                sorted_files[i + 1]->smallest_internal_key) >= 0) {
          return Status::InvalidArgument("Files have overlapping ranges");
        }
      }
@@ -430,6 +430,68 @@ TEST_F(ImportColumnFamilyTest, ImportExportedSSTFromAnotherDB) {
  test::DestroyDir(env_, dbname_ + "/db_copy");
 }

+TEST_F(ImportColumnFamilyTest, LevelFilesOverlappingAtEndpoints) {
+  // Imports a column family containing a level where two files overlap at their
+  // endpoints. "Overlap" means the largest user key in one file is the same as
+  // the smallest user key in the second file.
+  const int kFileBytes = 128 << 10;  // 128KB
+  const int kValueBytes = 1 << 10;   // 1KB
+  const int kNumFiles = 4;
+
+  Options options = CurrentOptions();
+  options.disable_auto_compactions = true;
+  options.num_levels = 2;
+  CreateAndReopenWithCF({"koko"}, options);
+
+  Random rnd(301);
+  // Every key is snapshot protected to ensure older versions will not be
+  // dropped during compaction.
+  std::vector<const Snapshot*> snapshots;
+  snapshots.reserve(kFileBytes / kValueBytes * kNumFiles);
+  for (int i = 0; i < kNumFiles; ++i) {
+    for (int j = 0; j < kFileBytes / kValueBytes; ++j) {
+      auto value = RandomString(&rnd, kValueBytes);
+      ASSERT_OK(Put(1, "key", value));
+      snapshots.push_back(db_->GetSnapshot());
+    }
+    ASSERT_OK(Flush(1));
+  }
+
+  // Compact to create overlapping L1 files.
+  ASSERT_OK(
+      db_->CompactRange(CompactRangeOptions(), handles_[1], nullptr, nullptr));
+  ASSERT_GT(NumTableFilesAtLevel(1, 1), 1);
+
+  Checkpoint* checkpoint;
+  ASSERT_OK(Checkpoint::Create(db_, &checkpoint));
+  ASSERT_OK(checkpoint->ExportColumnFamily(handles_[1], export_files_dir_,
+                                           &metadata_ptr_));
+  ASSERT_NE(metadata_ptr_, nullptr);
+  delete checkpoint;
+
+  // Create a new db and import the files.
+  DB* db_copy;
+  test::DestroyDir(env_, dbname_ + "/db_copy");
+  ASSERT_OK(DB::Open(options, dbname_ + "/db_copy", &db_copy));
+  ColumnFamilyHandle* cfh = nullptr;
+  ASSERT_OK(db_copy->CreateColumnFamilyWithImport(ColumnFamilyOptions(), "yoyo",
+                                                  ImportColumnFamilyOptions(),
+                                                  *metadata_ptr_, &cfh));
+  ASSERT_NE(cfh, nullptr);
+
+  {
+    std::string value;
+    ASSERT_OK(db_copy->Get(ReadOptions(), cfh, "key", &value));
+  }
+  db_copy->DropColumnFamily(cfh);
+  db_copy->DestroyColumnFamilyHandle(cfh);
+  delete db_copy;
+  test::DestroyDir(env_, dbname_ + "/db_copy");
+  for (const Snapshot* snapshot : snapshots) {
+    db_->ReleaseSnapshot(snapshot);
+  }
+}
+
 TEST_F(ImportColumnFamilyTest, ImportColumnFamilyNegativeTest) {
  Options options = CurrentOptions();
  CreateAndReopenWithCF({"koko"}, options);
@@ -102,8 +102,9 @@ struct SuperVersionContext {

 struct JobContext {
  inline bool HaveSomethingToDelete() const {
-    return full_scan_candidate_files.size() || sst_delete_files.size() ||
-           log_delete_files.size() || manifest_delete_files.size();
+    return !(full_scan_candidate_files.empty() && sst_delete_files.empty() &&
+             blob_delete_files.empty() && log_delete_files.empty() &&
+             manifest_delete_files.empty());
  }

  inline bool HaveSomethingToClean() const {
@@ -140,11 +141,17 @@ struct JobContext {
  std::vector<CandidateFileInfo> full_scan_candidate_files;

  // the list of all live sst files that cannot be deleted
-  std::vector<FileDescriptor> sst_live;
+  std::vector<uint64_t> sst_live;

-  // a list of sst files that we need to delete
+  // the list of sst files that we need to delete
  std::vector<ObsoleteFileInfo> sst_delete_files;

+  // the list of all live blob files that cannot be deleted
+  std::vector<uint64_t> blob_live;
+
+  // the list of blob files that we need to delete
+  std::vector<ObsoleteBlobFileInfo> blob_delete_files;
+
  // a list of log files that we need to delete
  std::vector<uint64_t> log_delete_files;

@@ -11,11 +11,11 @@

 #include <stdio.h>
 #include "file/sequence_file_reader.h"
+#include "port/lang.h"
 #include "rocksdb/env.h"
 #include "test_util/sync_point.h"
 #include "util/coding.h"
 #include "util/crc32c.h"
-#include "util/util.h"

 namespace ROCKSDB_NAMESPACE {
 namespace log {
@@ -49,7 +49,6 @@ class Reader {
  //
  // If "checksum" is true, verify checksums if available.
  Reader(std::shared_ptr<Logger> info_log,
-         // @lint-ignore TXT2 T25377293 Grandfathered in
         std::unique_ptr<SequentialFileReader>&& file, Reporter* reporter,
         bool checksum, uint64_t log_num);
  // No copying allowed
@@ -159,7 +158,6 @@ class Reader {
 class FragmentBufferedReader : public Reader {
 public:
  FragmentBufferedReader(std::shared_ptr<Logger> info_log,
-                         // @lint-ignore TXT2 T25377293 Grandfathered in
                         std::unique_ptr<SequentialFileReader>&& _file,
                         Reporter* reporter, bool checksum, uint64_t log_num)
      : Reader(info_log, std::move(_file), reporter, checksum, log_num),
@@ -23,6 +23,7 @@
 #include "memory/memory_usage.h"
 #include "monitoring/perf_context_imp.h"
 #include "monitoring/statistics.h"
+#include "port/lang.h"
 #include "port/port.h"
 #include "rocksdb/comparator.h"
 #include "rocksdb/env.h"
@@ -36,7 +37,6 @@
 #include "util/autovector.h"
 #include "util/coding.h"
 #include "util/mutexlock.h"
-#include "util/util.h"

 namespace ROCKSDB_NAMESPACE {

@@ -10,6 +10,7 @@
 #ifndef ROCKSDB_LITE

 #include <stdlib.h>
+#include <algorithm>
 #include <map>
 #include <string>
 #include <vector>
@@ -193,6 +194,124 @@ TEST_F(ObsoleteFilesTest, DeleteObsoleteOptionsFile) {
  ASSERT_EQ(2, opts_file_count);
 }

+TEST_F(ObsoleteFilesTest, BlobFiles) {
+  VersionSet* const versions = dbfull()->TEST_GetVersionSet();
+  assert(versions);
+  assert(versions->GetColumnFamilySet());
+
+  ColumnFamilyData* const cfd = versions->GetColumnFamilySet()->GetDefault();
+  assert(cfd);
+
+  // Add a blob file that consists of nothing but garbage (and is thus obsolete)
+  // and another one that is live.
+  VersionEdit edit;
+
+  constexpr uint64_t first_blob_file_number = 234;
+  constexpr uint64_t first_total_blob_count = 555;
+  constexpr uint64_t first_total_blob_bytes = 66666;
+  constexpr char first_checksum_method[] = "CRC32";
+  constexpr char first_checksum_value[] = "3d87ff57";
+
+  edit.AddBlobFile(first_blob_file_number, first_total_blob_count,
+                   first_total_blob_bytes, first_checksum_method,
+                   first_checksum_value);
+  edit.AddBlobFileGarbage(first_blob_file_number, first_total_blob_count,
+                          first_total_blob_bytes);
+
+  constexpr uint64_t second_blob_file_number = 456;
+  constexpr uint64_t second_total_blob_count = 100;
+  constexpr uint64_t second_total_blob_bytes = 2000000;
+  constexpr char second_checksum_method[] = "CRC32B";
+  constexpr char second_checksum_value[] = "6dbdf23a";
+  edit.AddBlobFile(second_blob_file_number, second_total_blob_count,
+                   second_total_blob_bytes, second_checksum_method,
+                   second_checksum_value);
+
+  dbfull()->TEST_LockMutex();
+  Status s = versions->LogAndApply(cfd, *cfd->GetLatestMutableCFOptions(),
+                                   &edit, dbfull()->mutex());
+  dbfull()->TEST_UnlockMutex();
+
+  ASSERT_OK(s);
+
+  // Check for obsolete files and make sure the first blob file is picked up
+  // and grabbed for purge. The second blob file should be on the live list.
+  constexpr int job_id = 0;
+  JobContext job_context{job_id};
+
+  dbfull()->TEST_LockMutex();
+  constexpr bool force_full_scan = false;
+  dbfull()->FindObsoleteFiles(&job_context, force_full_scan);
+  dbfull()->TEST_UnlockMutex();
+
+  ASSERT_TRUE(job_context.HaveSomethingToDelete());
+  ASSERT_EQ(job_context.blob_delete_files.size(), 1);
+  ASSERT_EQ(job_context.blob_delete_files[0].GetBlobFileNumber(),
+            first_blob_file_number);
+
+  const auto& files_grabbed_for_purge =
+      dbfull()->TEST_GetFilesGrabbedForPurge();
+  ASSERT_NE(files_grabbed_for_purge.find(first_blob_file_number),
+            files_grabbed_for_purge.end());
+
+  ASSERT_EQ(job_context.blob_live.size(), 1);
+  ASSERT_EQ(job_context.blob_live[0], second_blob_file_number);
+
+  // Hack the job context a bit by adding a few files to the full scan
+  // list and adjusting the pending file number. We add the two files
+  // above as well as two additional ones, where one is old
+  // and should be cleaned up, and the other is still pending.
+  assert(cfd->ioptions());
+  assert(!cfd->ioptions()->cf_paths.empty());
+  const std::string& path = cfd->ioptions()->cf_paths.front().path;
+
+  constexpr uint64_t old_blob_file_number = 123;
+  constexpr uint64_t pending_blob_file_number = 567;
+
+  job_context.full_scan_candidate_files.emplace_back(
+      BlobFileName(old_blob_file_number), path);
+  job_context.full_scan_candidate_files.emplace_back(
+      BlobFileName(first_blob_file_number), path);
+  job_context.full_scan_candidate_files.emplace_back(
+      BlobFileName(second_blob_file_number), path);
+  job_context.full_scan_candidate_files.emplace_back(
+      BlobFileName(pending_blob_file_number), path);
+
+  job_context.min_pending_output = pending_blob_file_number;
+
+  // Purge obsolete files and make sure we purge the old file and the first file
+  // (and keep the second file and the pending file).
+  std::vector<std::string> deleted_files;
+  SyncPoint::GetInstance()->SetCallBack(
+      "DBImpl::DeleteObsoleteFileImpl::BeforeDeletion", [&](void* arg) {
+        const std::string* file = static_cast<std::string*>(arg);
+        assert(file);
+
+        constexpr char blob_extension[] = ".blob";
+
+        if (file->find(blob_extension) != std::string::npos) {
+          deleted_files.emplace_back(*file);
+        }
+      });
+  SyncPoint::GetInstance()->EnableProcessing();
+
+  dbfull()->PurgeObsoleteFiles(job_context);
+  job_context.Clean();
+
+  SyncPoint::GetInstance()->DisableProcessing();
+  SyncPoint::GetInstance()->ClearAllCallBacks();
+
+  ASSERT_EQ(files_grabbed_for_purge.find(first_blob_file_number),
+            files_grabbed_for_purge.end());
+
+  std::sort(deleted_files.begin(), deleted_files.end());
+  const std::vector<std::string> expected_deleted_files{
+      BlobFileName(path, old_blob_file_number),
+      BlobFileName(path, first_blob_file_number)};
+
+  ASSERT_EQ(deleted_files, expected_deleted_files);
+}
+
 }  // namespace ROCKSDB_NAMESPACE

 #ifdef ROCKSDB_UNITTESTS_WITH_CUSTOM_OBJECTS_FROM_STATIC_LIBS
@@ -251,7 +251,7 @@ void ProfileQueries(bool enabled_time = false) {
  }

  if (FLAGS_random_key) {
-    std::random_shuffle(keys.begin(), keys.end());
+    RandomShuffle(std::begin(keys), std::end(keys));
  }
 #ifndef NDEBUG
  ThreadStatusUtil::TEST_SetStateDelay(ThreadStatus::STATE_MUTEX_WAIT, 1U);
@@ -524,7 +524,7 @@ TEST_F(PerfContextTest, SeekKeyComparison) {
  }

  if (FLAGS_random_key) {
-    std::random_shuffle(keys.begin(), keys.end());
+    RandomShuffle(std::begin(keys), std::end(keys));
  }

  HistogramImpl hist_put_time;
@@ -529,7 +529,8 @@ class Repairer {
          /*table_reader_ptr=*/nullptr, /*file_read_hist=*/nullptr,
          TableReaderCaller::kRepair, /*arena=*/nullptr, /*skip_filters=*/false,
          /*level=*/-1, /*smallest_compaction_key=*/nullptr,
-          /*largest_compaction_key=*/nullptr);
+          /*largest_compaction_key=*/nullptr,
+          /*allow_unprepared_value=*/false);
      ParsedInternalKey parsed;
      for (iter->SeekToFirst(); iter->Valid(); iter->Next()) {
        Slice key = iter->key();
@@ -62,6 +62,8 @@ void AppendVarint64(IterKey* key, uint64_t v) {

 }  // namespace

+const int kLoadConcurency = 128;
+
 TableCache::TableCache(const ImmutableCFOptions& ioptions,
                       const FileOptions& file_options, Cache* const cache,
                       BlockCacheTracer* const block_cache_tracer)
@@ -69,7 +71,8 @@ TableCache::TableCache(const ImmutableCFOptions& ioptions,
      file_options_(file_options),
      cache_(cache),
      immortal_tables_(false),
-      block_cache_tracer_(block_cache_tracer) {
+      block_cache_tracer_(block_cache_tracer),
+      loader_mutex_(kLoadConcurency, GetSliceNPHash64) {
  if (ioptions_.row_cache) {
    // If the same cache is shared by multiple instances, we need to
    // disambiguate its entries.
@@ -155,6 +158,13 @@ Status TableCache::FindTable(const FileOptions& file_options,
    if (no_io) {  // Don't do IO and return a not-found status
      return Status::Incomplete("Table not found in table_cache, no_io is set");
    }
+    MutexLock load_lock(loader_mutex_.get(key));
+    // We check the cache again under loading mutex
+    *handle = cache_->Lookup(key);
+    if (*handle != nullptr) {
+      return s;
+    }
+
    std::unique_ptr<TableReader> table_reader;
    s = GetTableReader(file_options, internal_comparator, fd,
                       false /* sequential mode */, record_read_stats,
@@ -184,7 +194,7 @@ InternalIterator* TableCache::NewIterator(
    TableReader** table_reader_ptr, HistogramImpl* file_read_hist,
    TableReaderCaller caller, Arena* arena, bool skip_filters, int level,
    const InternalKey* smallest_compaction_key,
-    const InternalKey* largest_compaction_key) {
+    const InternalKey* largest_compaction_key, bool allow_unprepared_value) {
  PERF_TIMER_GUARD(new_table_iterator_nanos);

  Status s;
@@ -213,7 +223,8 @@ InternalIterator* TableCache::NewIterator(
    } else {
      result = table_reader->NewIterator(options, prefix_extractor, arena,
                                   skip_filters, caller,
-                                   file_options.compaction_readahead_size);
+                                   file_options.compaction_readahead_size,
+                                   allow_unprepared_value);
    }
    if (handle != nullptr) {
      result->RegisterCleanup(&UnrefEntry, cache_, handle);
@@ -303,8 +314,7 @@ void TableCache::CreateRowCacheKeyPrefix(const ReadOptions& options,
  // Maybe we can include the whole file ifsnapshot == fd.largest_seqno.
  if (options.snapshot != nullptr &&
      (get_context->has_callback() ||
-       static_cast_with_check<const SnapshotImpl, const Snapshot>(
-           options.snapshot)
+       static_cast_with_check<const SnapshotImpl>(options.snapshot)
               ->GetSequenceNumber() <= fd.largest_seqno)) {
    // We should consider to use options.snapshot->GetSequenceNumber()
    // instead of GetInternalKeySeqno(k), which will make the code
@@ -73,7 +73,7 @@ class TableCache {
      const SliceTransform* prefix_extractor, TableReader** table_reader_ptr,
      HistogramImpl* file_read_hist, TableReaderCaller caller, Arena* arena,
      bool skip_filters, int level, const InternalKey* smallest_compaction_key,
-      const InternalKey* largest_compaction_key);
+      const InternalKey* largest_compaction_key, bool allow_unprepared_value);

  // If a seek to internal key "k" in specified file finds an entry,
  // call get_context->SaveValue() repeatedly until
@@ -221,6 +221,7 @@ class TableCache {
  std::string row_cache_id_;
  bool immortal_tables_;
  BlockCacheTracer* const block_cache_tracer_;
+  Striped<port::Mutex, Slice> loader_mutex_;
 };

 }  // namespace ROCKSDB_NAMESPACE
@@ -87,9 +87,10 @@ class VersionBuilder::Rep {
  };

  const FileOptions& file_options_;
-  Logger* info_log_;
+  const ImmutableCFOptions* const ioptions_;
  TableCache* table_cache_;
  VersionStorageInfo* base_vstorage_;
+  VersionSet* version_set_;
  int num_levels_;
  LevelState* levels_;
  // Store states of levels larger than num_levels_. We do this instead of
@@ -107,15 +108,18 @@ class VersionBuilder::Rep {
  std::map<uint64_t, std::shared_ptr<BlobFileMetaData>> changed_blob_files_;

 public:
-  Rep(const FileOptions& file_options, Logger* info_log,
-      TableCache* table_cache,
-      VersionStorageInfo* base_vstorage)
+  Rep(const FileOptions& file_options, const ImmutableCFOptions* ioptions,
+      TableCache* table_cache, VersionStorageInfo* base_vstorage,
+      VersionSet* version_set)
      : file_options_(file_options),
-        info_log_(info_log),
+        ioptions_(ioptions),
        table_cache_(table_cache),
        base_vstorage_(base_vstorage),
+        version_set_(version_set),
        num_levels_(base_vstorage->num_levels()),
        has_invalid_levels_(false) {
+    assert(ioptions_);
+
    levels_ = new LevelState[num_levels_];
    level_zero_cmp_.sort_method = FileComparator::kLevel0;
    level_nonzero_cmp_.sort_method = FileComparator::kLevelNon0;
@@ -232,11 +236,11 @@ class VersionBuilder::Rep {

        auto f1 = level_files[i - 1];
        auto f2 = level_files[i];
-#ifndef NDEBUG
-        auto pair = std::make_pair(&f1, &f2);
-        TEST_SYNC_POINT_CALLBACK("VersionBuilder::CheckConsistency", &pair);
-#endif
        if (level == 0) {
+#ifndef NDEBUG
+          auto pair = std::make_pair(&f1, &f2);
+          TEST_SYNC_POINT_CALLBACK("VersionBuilder::CheckConsistency0", &pair);
+#endif
          if (!level_zero_cmp_(f1, f2)) {
            fprintf(stderr, "L0 files are not sorted properly");
            return Status::Corruption("L0 files are not sorted properly");
@@ -275,6 +279,10 @@ class VersionBuilder::Rep {
                NumberToString(f2->fd.GetNumber()));
          }
        } else {
+#ifndef NDEBUG
+          auto pair = std::make_pair(&f1, &f2);
+          TEST_SYNC_POINT_CALLBACK("VersionBuilder::CheckConsistency1", &pair);
+#endif
          if (!level_nonzero_cmp_(f1, f2)) {
            fprintf(stderr, "L%d files are not sorted properly", level);
            return Status::Corruption("L" + NumberToString(level) +
@@ -312,7 +320,10 @@ class VersionBuilder::Rep {
      }
    }

-    return Status::OK();
+    Status ret_s;
+    TEST_SYNC_POINT_CALLBACK("VersionBuilder::CheckConsistencyBeforeReturn",
+                             &ret_s);
+    return ret_s;
  }

  Status CheckConsistencyForDeletes(VersionEdit* /*edit*/, uint64_t number,
@@ -388,15 +399,33 @@ class VersionBuilder::Rep {
      return Status::Corruption("VersionBuilder", oss.str());
    }

-    auto shared_meta = std::make_shared<SharedBlobFileMetaData>(
+    // Note: we use C++11 for now but in C++14, this could be done in a more
+    // elegant way using generalized lambda capture.
+    VersionSet* const vs = version_set_;
+    const ImmutableCFOptions* const ioptions = ioptions_;
+
+    auto deleter = [vs, ioptions](SharedBlobFileMetaData* shared_meta) {
+      if (vs) {
+        assert(ioptions);
+        assert(!ioptions->cf_paths.empty());
+        assert(shared_meta);
+
+        vs->AddObsoleteBlobFile(shared_meta->GetBlobFileNumber(),
+                                ioptions->cf_paths.front().path);
+      }
+
+      delete shared_meta;
+    };
+
+    auto shared_meta = SharedBlobFileMetaData::Create(
        blob_file_number, blob_file_addition.GetTotalBlobCount(),
        blob_file_addition.GetTotalBlobBytes(),
        blob_file_addition.GetChecksumMethod(),
-        blob_file_addition.GetChecksumValue());
+        blob_file_addition.GetChecksumValue(), deleter);

    constexpr uint64_t garbage_blob_count = 0;
    constexpr uint64_t garbage_blob_bytes = 0;
-    auto new_meta = std::make_shared<BlobFileMetaData>(
+    auto new_meta = BlobFileMetaData::Create(
        std::move(shared_meta), garbage_blob_count, garbage_blob_bytes);

    changed_blob_files_.emplace(blob_file_number, std::move(new_meta));
@@ -417,7 +446,7 @@ class VersionBuilder::Rep {

    assert(meta->GetBlobFileNumber() == blob_file_number);

-    auto new_meta = std::make_shared<BlobFileMetaData>(
+    auto new_meta = BlobFileMetaData::Create(
        meta->GetSharedMeta(),
        meta->GetGarbageBlobCount() + blob_file_garbage.GetGarbageBlobCount(),
        meta->GetGarbageBlobBytes() + blob_file_garbage.GetGarbageBlobBytes());
@@ -441,7 +470,10 @@ class VersionBuilder::Rep {
      const auto number = del_file.second;
      if (level < num_levels_) {
        levels_[level].deleted_files.insert(number);
-        CheckConsistencyForDeletes(edit, number, level);
+        s = CheckConsistencyForDeletes(edit, number, level);
+        if (!s.ok()) {
+          return s;
+        }

        auto exising = levels_[level].added_files.find(number);
        if (exising != levels_[level].added_files.end()) {
@@ -738,16 +770,19 @@ class VersionBuilder::Rep {
      // f is to-be-deleted table file
      vstorage->RemoveCurrentStats(f);
    } else {
-      vstorage->AddFile(level, f, info_log_);
+      assert(ioptions_);
+      vstorage->AddFile(level, f, ioptions_->info_log);
    }
  }
 };

 VersionBuilder::VersionBuilder(const FileOptions& file_options,
+                               const ImmutableCFOptions* ioptions,
                               TableCache* table_cache,
                               VersionStorageInfo* base_vstorage,
-                               Logger* info_log)
-    : rep_(new Rep(file_options, info_log, table_cache, base_vstorage)) {}
+                               VersionSet* version_set)
+    : rep_(new Rep(file_options, ioptions, table_cache, base_vstorage,
+                   version_set)) {}

 VersionBuilder::~VersionBuilder() = default;

@@ -773,8 +808,9 @@ Status VersionBuilder::LoadTableHandlers(
 BaseReferencedVersionBuilder::BaseReferencedVersionBuilder(
    ColumnFamilyData* cfd)
    : version_builder_(new VersionBuilder(
-          cfd->current()->version_set()->file_options(), cfd->table_cache(),
-          cfd->current()->storage_info(), cfd->ioptions()->info_log)),
+          cfd->current()->version_set()->file_options(), cfd->ioptions(),
+          cfd->table_cache(), cfd->current()->storage_info(),
+          cfd->current()->version_set())),
      version_(cfd->current()) {
  version_->Ref();
 }
@@ -782,8 +818,8 @@ BaseReferencedVersionBuilder::BaseReferencedVersionBuilder(
 BaseReferencedVersionBuilder::BaseReferencedVersionBuilder(
    ColumnFamilyData* cfd, Version* v)
    : version_builder_(new VersionBuilder(
-          cfd->current()->version_set()->file_options(), cfd->table_cache(),
-          v->storage_info(), cfd->ioptions()->info_log)),
+          cfd->current()->version_set()->file_options(), cfd->ioptions(),
+          cfd->table_cache(), v->storage_info(), v->version_set())),
      version_(v) {
  assert(version_ != cfd->current());
 }
@@ -16,12 +16,14 @@

 namespace ROCKSDB_NAMESPACE {

+struct ImmutableCFOptions;
 class TableCache;
 class VersionStorageInfo;
 class VersionEdit;
 struct FileMetaData;
 class InternalStats;
 class Version;
+class VersionSet;
 class ColumnFamilyData;

 // A helper class so we can efficiently apply a whole sequence
@@ -29,8 +31,9 @@ class ColumnFamilyData;
 // Versions that contain full copies of the intermediate state.
 class VersionBuilder {
 public:
-  VersionBuilder(const FileOptions& file_options, TableCache* table_cache,
-                 VersionStorageInfo* base_vstorage, Logger* info_log = nullptr);
+  VersionBuilder(const FileOptions& file_options,
+                 const ImmutableCFOptions* ioptions, TableCache* table_cache,
+                 VersionStorageInfo* base_vstorage, VersionSet* version_set);
  ~VersionBuilder();

  bool CheckConsistencyForNumLevels();
@@ -82,10 +82,10 @@ class VersionBuilderTest : public testing::Test {
               uint64_t total_blob_bytes, std::string checksum_method,
               std::string checksum_value, uint64_t garbage_blob_count,
               uint64_t garbage_blob_bytes) {
-    auto shared_meta = std::make_shared<SharedBlobFileMetaData>(
+    auto shared_meta = SharedBlobFileMetaData::Create(
        blob_file_number, total_blob_count, total_blob_bytes,
        std::move(checksum_method), std::move(checksum_value));
-    auto meta = std::make_shared<BlobFileMetaData>(
+    auto meta = BlobFileMetaData::Create(
        std::move(shared_meta), garbage_blob_count, garbage_blob_bytes);

    vstorage_.AddBlobFile(std::move(meta));
@@ -152,8 +152,11 @@ TEST_F(VersionBuilderTest, ApplyAndSaveTo) {
  version_edit.DeleteFile(3, 27U);

  EnvOptions env_options;
+  constexpr TableCache* table_cache = nullptr;
+  constexpr VersionSet* version_set = nullptr;

-  VersionBuilder version_builder(env_options, nullptr, &vstorage_);
+  VersionBuilder version_builder(env_options, &ioptions_, table_cache,
+                                 &vstorage_, version_set);

  VersionStorageInfo new_vstorage(&icmp_, ucmp_, options_.num_levels,
                                  kCompactionStyleLevel, nullptr, false);
@@ -190,8 +193,11 @@ TEST_F(VersionBuilderTest, ApplyAndSaveToDynamic) {
  version_edit.DeleteFile(0, 88U);

  EnvOptions env_options;
+  constexpr TableCache* table_cache = nullptr;
+  constexpr VersionSet* version_set = nullptr;

-  VersionBuilder version_builder(env_options, nullptr, &vstorage_);
+  VersionBuilder version_builder(env_options, &ioptions_, table_cache,
+                                 &vstorage_, version_set);

  VersionStorageInfo new_vstorage(&icmp_, ucmp_, options_.num_levels,
                                  kCompactionStyleLevel, nullptr, false);
@@ -233,8 +239,11 @@ TEST_F(VersionBuilderTest, ApplyAndSaveToDynamic2) {
  version_edit.DeleteFile(4, 8U);

  EnvOptions env_options;
+  constexpr TableCache* table_cache = nullptr;
+  constexpr VersionSet* version_set = nullptr;

-  VersionBuilder version_builder(env_options, nullptr, &vstorage_);
+  VersionBuilder version_builder(env_options, &ioptions_, table_cache,
+                                 &vstorage_, version_set);

  VersionStorageInfo new_vstorage(&icmp_, ucmp_, options_.num_levels,
                                  kCompactionStyleLevel, nullptr, false);
@@ -279,8 +288,11 @@ TEST_F(VersionBuilderTest, ApplyMultipleAndSaveTo) {
                       kUnknownFileChecksumFuncName);

  EnvOptions env_options;
+  constexpr TableCache* table_cache = nullptr;
+  constexpr VersionSet* version_set = nullptr;

-  VersionBuilder version_builder(env_options, nullptr, &vstorage_);
+  VersionBuilder version_builder(env_options, &ioptions_, table_cache,
+                                 &vstorage_, version_set);

  VersionStorageInfo new_vstorage(&icmp_, ucmp_, options_.num_levels,
                                  kCompactionStyleLevel, nullptr, false);
@@ -296,7 +308,12 @@ TEST_F(VersionBuilderTest, ApplyDeleteAndSaveTo) {
  UpdateVersionStorageInfo();

  EnvOptions env_options;
-  VersionBuilder version_builder(env_options, nullptr, &vstorage_);
+  constexpr TableCache* table_cache = nullptr;
+  constexpr VersionSet* version_set = nullptr;
+
+  VersionBuilder version_builder(env_options, &ioptions_, table_cache,
+                                 &vstorage_, version_set);
+
  VersionStorageInfo new_vstorage(&icmp_, ucmp_, options_.num_levels,
                                  kCompactionStyleLevel, nullptr, false);

@@ -353,7 +370,10 @@ TEST_F(VersionBuilderTest, ApplyDeleteAndSaveTo) {
 TEST_F(VersionBuilderTest, ApplyBlobFileAddition) {
  EnvOptions env_options;
  constexpr TableCache* table_cache = nullptr;
-  VersionBuilder builder(env_options, table_cache, &vstorage_);
+  constexpr VersionSet* version_set = nullptr;
+
+  VersionBuilder builder(env_options, &ioptions_, table_cache, &vstorage_,
+                         version_set);

  VersionEdit edit;

@@ -406,7 +426,10 @@ TEST_F(VersionBuilderTest, ApplyBlobFileAdditionAlreadyInBase) {

  EnvOptions env_options;
  constexpr TableCache* table_cache = nullptr;
-  VersionBuilder builder(env_options, table_cache, &vstorage_);
+  constexpr VersionSet* version_set = nullptr;
+
+  VersionBuilder builder(env_options, &ioptions_, table_cache, &vstorage_,
+                         version_set);

  VersionEdit edit;

@@ -423,7 +446,10 @@ TEST_F(VersionBuilderTest, ApplyBlobFileAdditionAlreadyApplied) {

  EnvOptions env_options;
  constexpr TableCache* table_cache = nullptr;
-  VersionBuilder builder(env_options, table_cache, &vstorage_);
+  constexpr VersionSet* version_set = nullptr;
+
+  VersionBuilder builder(env_options, &ioptions_, table_cache, &vstorage_,
+                         version_set);

  VersionEdit edit;

@@ -463,7 +489,10 @@ TEST_F(VersionBuilderTest, ApplyBlobFileGarbageFileInBase) {

  EnvOptions env_options;
  constexpr TableCache* table_cache = nullptr;
-  VersionBuilder builder(env_options, table_cache, &vstorage_);
+  constexpr VersionSet* version_set = nullptr;
+
+  VersionBuilder builder(env_options, &ioptions_, table_cache, &vstorage_,
+                         version_set);

  VersionEdit edit;

@@ -505,7 +534,10 @@ TEST_F(VersionBuilderTest, ApplyBlobFileGarbageFileAdditionApplied) {

  EnvOptions env_options;
  constexpr TableCache* table_cache = nullptr;
-  VersionBuilder builder(env_options, table_cache, &vstorage_);
+  constexpr VersionSet* version_set = nullptr;
+
+  VersionBuilder builder(env_options, &ioptions_, table_cache, &vstorage_,
+                         version_set);

  VersionEdit addition;

@@ -558,7 +590,10 @@ TEST_F(VersionBuilderTest, ApplyBlobFileGarbageFileNotFound) {

  EnvOptions env_options;
  constexpr TableCache* table_cache = nullptr;
-  VersionBuilder builder(env_options, table_cache, &vstorage_);
+  constexpr VersionSet* version_set = nullptr;
+
+  VersionBuilder builder(env_options, &ioptions_, table_cache, &vstorage_,
+                         version_set);

  VersionEdit edit;

@@ -591,7 +626,10 @@ TEST_F(VersionBuilderTest, SaveBlobFilesTo) {

  EnvOptions env_options;
  constexpr TableCache* table_cache = nullptr;
-  VersionBuilder builder(env_options, table_cache, &vstorage_);
+  constexpr VersionSet* version_set = nullptr;
+
+  VersionBuilder builder(env_options, &ioptions_, table_cache, &vstorage_,
+                         version_set);

  VersionEdit edit;

@@ -681,7 +719,10 @@ TEST_F(VersionBuilderTest, CheckConsistencyForBlobFiles) {
  // new table file--blob file pair.
  EnvOptions env_options;
  constexpr TableCache* table_cache = nullptr;
-  VersionBuilder builder(env_options, table_cache, &vstorage_);
+  constexpr VersionSet* version_set = nullptr;
+
+  VersionBuilder builder(env_options, &ioptions_, table_cache, &vstorage_,
+                         version_set);

  VersionEdit edit;

@@ -739,7 +780,10 @@ TEST_F(VersionBuilderTest, CheckConsistencyForBlobFilesNotInVersion) {

  EnvOptions env_options;
  constexpr TableCache* table_cache = nullptr;
-  VersionBuilder builder(env_options, table_cache, &vstorage_);
+  constexpr VersionSet* version_set = nullptr;
+
+  VersionBuilder builder(env_options, &ioptions_, table_cache, &vstorage_,
+                         version_set);

  // Save to a new version in order to trigger consistency checks.
  constexpr bool force_consistency_checks = true;
@@ -776,7 +820,10 @@ TEST_F(VersionBuilderTest, CheckConsistencyForBlobFilesAllGarbage) {

  EnvOptions env_options;
  constexpr TableCache* table_cache = nullptr;
-  VersionBuilder builder(env_options, table_cache, &vstorage_);
+  constexpr VersionSet* version_set = nullptr;
+
+  VersionBuilder builder(env_options, &ioptions_, table_cache, &vstorage_,
+                         version_set);

  // Save to a new version in order to trigger consistency checks.
  constexpr bool force_consistency_checks = true;
@@ -792,6 +839,36 @@ TEST_F(VersionBuilderTest, CheckConsistencyForBlobFilesAllGarbage) {
  UnrefFilesInVersion(&new_vstorage);
 }

+TEST_F(VersionBuilderTest, CheckConsistencyForFileDeletedTwice) {
+  Add(0, 1U, "150", "200", 100U);
+  UpdateVersionStorageInfo();
+
+  VersionEdit version_edit;
+  version_edit.DeleteFile(0, 1U);
+
+  EnvOptions env_options;
+  constexpr TableCache* table_cache = nullptr;
+  constexpr VersionSet* version_set = nullptr;
+
+  VersionBuilder version_builder(env_options, &ioptions_, table_cache,
+                                 &vstorage_, version_set);
+  VersionStorageInfo new_vstorage(&icmp_, ucmp_, options_.num_levels,
+                                  kCompactionStyleLevel, nullptr,
+                                  true /* force_consistency_checks */);
+  ASSERT_OK(version_builder.Apply(&version_edit));
+  ASSERT_OK(version_builder.SaveTo(&new_vstorage));
+
+  VersionBuilder version_builder2(env_options, &ioptions_, table_cache,
+                                 &new_vstorage, version_set);
+  VersionStorageInfo new_vstorage2(&icmp_, ucmp_, options_.num_levels,
+                                  kCompactionStyleLevel, nullptr,
+                                  true /* force_consistency_checks */);
+  ASSERT_NOK(version_builder2.Apply(&version_edit));
+
+  UnrefFilesInVersion(&new_vstorage);
+  UnrefFilesInVersion(&new_vstorage2);
+}
+
 TEST_F(VersionBuilderTest, EstimatedActiveKeys) {
  const uint32_t kTotalSamples = 20;
  const uint32_t kNumLevels = 5;
@@ -377,6 +377,7 @@ Status VersionEditHandler::MaybeCreateVersion(const VersionEdit& /*edit*/,
                                              ColumnFamilyData* cfd,
                                              bool force_create_version) {
  assert(cfd->initialized());
+  Status s;
  if (force_create_version) {
    auto builder_iter = builders_.find(cfd->GetID());
    assert(builder_iter != builders_.end());
@@ -384,13 +385,18 @@ Status VersionEditHandler::MaybeCreateVersion(const VersionEdit& /*edit*/,
    auto* v = new Version(cfd, version_set_, version_set_->file_options_,
                          *cfd->GetLatestMutableCFOptions(),
                          version_set_->current_version_number_++);
-    builder->SaveTo(v->storage_info());
-    // Install new version
-    v->PrepareApply(*cfd->GetLatestMutableCFOptions(),
-                    !(version_set_->db_options_->skip_stats_update_on_db_open));
-    version_set_->AppendVersion(cfd, v);
+    s = builder->SaveTo(v->storage_info());
+    if (s.ok()) {
+      // Install new version
+      v->PrepareApply(
+          *cfd->GetLatestMutableCFOptions(),
+          !(version_set_->db_options_->skip_stats_update_on_db_open));
+      version_set_->AppendVersion(cfd, v);
+    } else {
+      delete v;
+    }
  }
-  return Status::OK();
+  return s;
 }

 Status VersionEditHandler::LoadTables(ColumnFamilyData* cfd,
@@ -558,16 +564,20 @@ Status VersionEditHandlerPointInTime::MaybeCreateVersion(
    auto* version = new Version(cfd, version_set_, version_set_->file_options_,
                                *cfd->GetLatestMutableCFOptions(),
                                version_set_->current_version_number_++);
-    builder->SaveTo(version->storage_info());
-    version->PrepareApply(
-        *cfd->GetLatestMutableCFOptions(),
-        !version_set_->db_options_->skip_stats_update_on_db_open);
-    auto v_iter = versions_.find(cfd->GetID());
-    if (v_iter != versions_.end()) {
-      delete v_iter->second;
-      v_iter->second = version;
+    s = builder->SaveTo(version->storage_info());
+    if (s.ok()) {
+      version->PrepareApply(
+          *cfd->GetLatestMutableCFOptions(),
+          !version_set_->db_options_->skip_stats_update_on_db_open);
+      auto v_iter = versions_.find(cfd->GetID());
+      if (v_iter != versions_.end()) {
+        delete v_iter->second;
+        v_iter->second = version;
+      } else {
+        versions_.emplace(cfd->GetID(), version);
+      }
    } else {
-      versions_.emplace(cfd->GetID(), version);
+      delete version;
    }
  }
  return s;
@@ -861,7 +861,8 @@ class LevelIterator final : public InternalIterator {
                HistogramImpl* file_read_hist, TableReaderCaller caller,
                bool skip_filters, int level, RangeDelAggregator* range_del_agg,
                const std::vector<AtomicCompactionUnitBoundary>*
-                    compaction_boundaries = nullptr)
+                    compaction_boundaries = nullptr,
+                bool allow_unprepared_value = false)
      : table_cache_(table_cache),
        read_options_(read_options),
        file_options_(file_options),
@@ -873,6 +874,7 @@ class LevelIterator final : public InternalIterator {
        should_sample_(should_sample),
        caller_(caller),
        skip_filters_(skip_filters),
+        allow_unprepared_value_(allow_unprepared_value),
        file_index_(flevel_->num_files),
        level_(level),
        range_del_agg_(range_del_agg),
@@ -907,6 +909,10 @@ class LevelIterator final : public InternalIterator {
    return file_iter_.iter() ? file_iter_.status() : Status::OK();
  }

+  bool PrepareValue() override {
+    return file_iter_.PrepareValue();
+  }
+
  inline bool MayBeOutOfLowerBound() override {
    assert(Valid());
    return may_be_out_of_lower_bound_ && file_iter_.MayBeOutOfLowerBound();
@@ -979,7 +985,7 @@ class LevelIterator final : public InternalIterator {
        range_del_agg_, prefix_extractor_,
        nullptr /* don't need reference to table */, file_read_hist_, caller_,
        /*arena=*/nullptr, skip_filters_, level_, smallest_compaction_key,
-        largest_compaction_key);
+        largest_compaction_key, allow_unprepared_value_);
  }

  // Check if current file being fully within iterate_lower_bound.
@@ -990,9 +996,9 @@ class LevelIterator final : public InternalIterator {
    if (read_options_.iterate_lower_bound != nullptr &&
        file_index_ < flevel_->num_files) {
      may_be_out_of_lower_bound_ =
-          user_comparator_.Compare(
-              ExtractUserKey(file_smallest_key(file_index_)),
-              *read_options_.iterate_lower_bound) < 0;
+          user_comparator_.CompareWithoutTimestamp(
+              ExtractUserKey(file_smallest_key(file_index_)), /*a_has_ts=*/true,
+              *read_options_.iterate_lower_bound, /*b_has_ts=*/false) < 0;
    }
  }

@@ -1012,6 +1018,7 @@ class LevelIterator final : public InternalIterator {
  bool should_sample_;
  TableReaderCaller caller_;
  bool skip_filters_;
+  bool allow_unprepared_value_;
  bool may_be_out_of_lower_bound_ = true;
  size_t file_index_;
  int level_;
@@ -1117,6 +1124,7 @@ bool LevelIterator::NextAndGetResult(IterateResult* result) {
  if (is_valid) {
    result->key = key();
    result->may_be_out_of_upper_bound = MayBeOutOfUpperBound();
+    result->value_prepared = !allow_unprepared_value_;
  }
  return is_valid;
 }
@@ -1533,12 +1541,13 @@ double VersionStorageInfo::GetEstimatedCompressionRatioAtLevel(
 void Version::AddIterators(const ReadOptions& read_options,
                           const FileOptions& soptions,
                           MergeIteratorBuilder* merge_iter_builder,
-                           RangeDelAggregator* range_del_agg) {
+                           RangeDelAggregator* range_del_agg,
+                           bool allow_unprepared_value) {
  assert(storage_info_.finalized_);

  for (int level = 0; level < storage_info_.num_non_empty_levels(); level++) {
    AddIteratorsForLevel(read_options, soptions, merge_iter_builder, level,
-                         range_del_agg);
+                         range_del_agg, allow_unprepared_value);
  }
 }

@@ -1546,7 +1555,8 @@ void Version::AddIteratorsForLevel(const ReadOptions& read_options,
                                   const FileOptions& soptions,
                                   MergeIteratorBuilder* merge_iter_builder,
                                   int level,
-                                   RangeDelAggregator* range_del_agg) {
+                                   RangeDelAggregator* range_del_agg,
+                                   bool allow_unprepared_value) {
  assert(storage_info_.finalized_);
  if (level >= storage_info_.num_non_empty_levels()) {
    // This is an empty level
@@ -1571,7 +1581,8 @@ void Version::AddIteratorsForLevel(const ReadOptions& read_options,
          TableReaderCaller::kUserIterator, arena,
          /*skip_filters=*/false, /*level=*/0,
          /*smallest_compaction_key=*/nullptr,
-          /*largest_compaction_key=*/nullptr));
+          /*largest_compaction_key=*/nullptr,
+          allow_unprepared_value));
    }
    if (should_sample) {
      // Count ones for every L0 files. This is done per iterator creation
@@ -1593,7 +1604,8 @@ void Version::AddIteratorsForLevel(const ReadOptions& read_options,
        mutable_cf_options_.prefix_extractor.get(), should_sample_file_read(),
        cfd_->internal_stats()->GetFileReadHist(level),
        TableReaderCaller::kUserIterator, IsFilterSkipped(level), level,
-        range_del_agg, /*largest_compaction_key=*/nullptr));
+        range_del_agg, /*largest_compaction_key=*/nullptr,
+        allow_unprepared_value));
  }
 }

@@ -1629,7 +1641,8 @@ Status Version::OverlapWithLevelIterator(const ReadOptions& read_options,
          TableReaderCaller::kUserIterator, &arena,
          /*skip_filters=*/false, /*level=*/0,
          /*smallest_compaction_key=*/nullptr,
-          /*largest_compaction_key=*/nullptr));
+          /*largest_compaction_key=*/nullptr,
+          /*allow_unprepared_value=*/false));
      status = OverlapWithIterator(
          ucmp, smallest_user_key, largest_user_key, iter.get(), overlap);
      if (!status.ok() || *overlap) {
@@ -3401,13 +3414,27 @@ bool VersionStorageInfo::RangeMightExistAfterSortedRun(
  return false;
 }

-void Version::AddLiveFiles(std::vector<FileDescriptor>* live) {
-  for (int level = 0; level < storage_info_.num_levels(); level++) {
-    const std::vector<FileMetaData*>& files = storage_info_.files_[level];
-    for (const auto& file : files) {
-      live->push_back(file->fd);
+void Version::AddLiveFiles(std::vector<uint64_t>* live_table_files,
+                           std::vector<uint64_t>* live_blob_files) const {
+  assert(live_table_files);
+  assert(live_blob_files);
+
+  for (int level = 0; level < storage_info_.num_levels(); ++level) {
+    const auto& level_files = storage_info_.LevelFiles(level);
+    for (const auto& meta : level_files) {
+      assert(meta);
+
+      live_table_files->emplace_back(meta->fd.GetNumber());
    }
  }
+
+  const auto& blob_files = storage_info_.GetBlobFiles();
+  for (const auto& pair : blob_files) {
+    const auto& meta = pair.second;
+    assert(meta);
+
+    live_blob_files->emplace_back(meta->GetBlobFileNumber());
+  }
 }

 std::string Version::DebugString(bool hex, bool print_stats) const {
@@ -4581,7 +4608,11 @@ Status VersionSet::Recover(
      Version* v = new Version(cfd, this, file_options_,
                               *cfd->GetLatestMutableCFOptions(),
                               current_version_number_++);
-      builder->SaveTo(v->storage_info());
+      s = builder->SaveTo(v->storage_info());
+      if (!s.ok()) {
+        delete v;
+        return s;
+      }

      // Install recovered version
      v->PrepareApply(*cfd->GetLatestMutableCFOptions(),
@@ -5132,7 +5163,7 @@ Status VersionSet::DumpManifest(Options& options, std::string& dscname,
      Version* v = new Version(cfd, this, file_options_,
                               *cfd->GetLatestMutableCFOptions(),
                               current_version_number_++);
-      builder->SaveTo(v->storage_info());
+      s = builder->SaveTo(v->storage_info());
      v->PrepareApply(*cfd->GetLatestMutableCFOptions(), false);

      printf("--------------- Column family \"%s\"  (ID %" PRIu32
@@ -5211,6 +5242,8 @@ Status VersionSet::WriteCurrentStateToManifest(
  }

  for (auto cfd : *column_family_set_) {
+    assert(cfd);
+
    if (cfd->IsDropped()) {
      continue;
    }
@@ -5243,6 +5276,9 @@ Status VersionSet::WriteCurrentStateToManifest(
      VersionEdit edit;
      edit.SetColumnFamily(cfd->GetID());

+      assert(cfd->current());
+      assert(cfd->current()->storage_info());
+
      for (int level = 0; level < cfd->NumberLevels(); level++) {
        for (const auto& f :
             cfd->current()->storage_info()->LevelFiles(level)) {
@@ -5254,6 +5290,24 @@ Status VersionSet::WriteCurrentStateToManifest(
                       f->file_checksum, f->file_checksum_func_name);
        }
      }
+
+      const auto& blob_files = cfd->current()->storage_info()->GetBlobFiles();
+      for (const auto& pair : blob_files) {
+        const uint64_t blob_file_number = pair.first;
+        const auto& meta = pair.second;
+
+        assert(meta);
+        assert(blob_file_number == meta->GetBlobFileNumber());
+
+        edit.AddBlobFile(blob_file_number, meta->GetTotalBlobCount(),
+                         meta->GetTotalBlobBytes(), meta->GetChecksumMethod(),
+                         meta->GetChecksumValue());
+        if (meta->GetGarbageBlobCount() > 0) {
+          edit.AddBlobFileGarbage(blob_file_number, meta->GetGarbageBlobCount(),
+                                  meta->GetGarbageBlobBytes());
+        }
+      }
+
      const auto iter = curr_state.find(cfd->GetID());
      assert(iter != curr_state.end());
      uint64_t log_number = iter->second.log_number;
@@ -5471,44 +5525,70 @@ uint64_t VersionSet::ApproximateSize(Version* v, const FdWithKeyRange& f,
      v->GetMutableCFOptions().prefix_extractor.get());
 }

-void VersionSet::AddLiveFiles(std::vector<FileDescriptor>* live_list) {
+void VersionSet::AddLiveFiles(std::vector<uint64_t>* live_table_files,
+                              std::vector<uint64_t>* live_blob_files) const {
+  assert(live_table_files);
+  assert(live_blob_files);
+
  // pre-calculate space requirement
-  int64_t total_files = 0;
+  size_t total_table_files = 0;
+  size_t total_blob_files = 0;
+
+  assert(column_family_set_);
  for (auto cfd : *column_family_set_) {
+    assert(cfd);
+
    if (!cfd->initialized()) {
      continue;
    }
-    Version* dummy_versions = cfd->dummy_versions();
+
+    Version* const dummy_versions = cfd->dummy_versions();
+    assert(dummy_versions);
+
    for (Version* v = dummy_versions->next_; v != dummy_versions;
         v = v->next_) {
+      assert(v);
+
      const auto* vstorage = v->storage_info();
-      for (int level = 0; level < vstorage->num_levels(); level++) {
-        total_files += vstorage->LevelFiles(level).size();
+      assert(vstorage);
+
+      for (int level = 0; level < vstorage->num_levels(); ++level) {
+        total_table_files += vstorage->LevelFiles(level).size();
      }
+
+      total_blob_files += vstorage->GetBlobFiles().size();
    }
  }

  // just one time extension to the right size
-  live_list->reserve(live_list->size() + static_cast<size_t>(total_files));
+  live_table_files->reserve(live_table_files->size() + total_table_files);
+  live_blob_files->reserve(live_blob_files->size() + total_blob_files);

+  assert(column_family_set_);
  for (auto cfd : *column_family_set_) {
+    assert(cfd);
    if (!cfd->initialized()) {
      continue;
    }
+
    auto* current = cfd->current();
    bool found_current = false;
-    Version* dummy_versions = cfd->dummy_versions();
+
+    Version* const dummy_versions = cfd->dummy_versions();
+    assert(dummy_versions);
+
    for (Version* v = dummy_versions->next_; v != dummy_versions;
         v = v->next_) {
-      v->AddLiveFiles(live_list);
+      v->AddLiveFiles(live_table_files, live_blob_files);
      if (v == current) {
        found_current = true;
      }
    }
+
    if (!found_current && current != nullptr) {
      // Should never happen unless it is a bug.
      assert(false);
-      current->AddLiveFiles(live_list);
+      current->AddLiveFiles(live_table_files, live_blob_files);
    }
  }
 }
@@ -5549,7 +5629,8 @@ InternalIterator* VersionSet::MakeInputIterator(
              /*arena=*/nullptr,
              /*skip_filters=*/false, /*level=*/static_cast<int>(which),
              /*smallest_compaction_key=*/nullptr,
-              /*largest_compaction_key=*/nullptr);
+              /*largest_compaction_key=*/nullptr,
+              /*allow_unprepared_value=*/false);
        }
      } else {
        // Create concatenating iterator for the files from this level
@@ -5688,19 +5769,37 @@ void VersionSet::GetLiveFilesMetaData(std::vector<LiveFileMetaData>* metadata) {
 }

 void VersionSet::GetObsoleteFiles(std::vector<ObsoleteFileInfo>* files,
+                                  std::vector<ObsoleteBlobFileInfo>* blob_files,
                                  std::vector<std::string>* manifest_filenames,
                                  uint64_t min_pending_output) {
+  assert(files);
+  assert(blob_files);
+  assert(manifest_filenames);
+  assert(files->empty());
+  assert(blob_files->empty());
  assert(manifest_filenames->empty());
-  obsolete_manifests_.swap(*manifest_filenames);
+
  std::vector<ObsoleteFileInfo> pending_files;
  for (auto& f : obsolete_files_) {
    if (f.metadata->fd.GetNumber() < min_pending_output) {
-      files->push_back(std::move(f));
+      files->emplace_back(std::move(f));
    } else {
-      pending_files.push_back(std::move(f));
+      pending_files.emplace_back(std::move(f));
    }
  }
  obsolete_files_.swap(pending_files);
+
+  std::vector<ObsoleteBlobFileInfo> pending_blob_files;
+  for (auto& blob_file : obsolete_blob_files_) {
+    if (blob_file.GetBlobFileNumber() < min_pending_output) {
+      blob_files->emplace_back(std::move(blob_file));
+    } else {
+      pending_blob_files.emplace_back(std::move(blob_file));
+    }
+  }
+  obsolete_blob_files_.swap(pending_blob_files);
+
+  obsolete_manifests_.swap(*manifest_filenames);
 }

 ColumnFamilyData* VersionSet::CreateColumnFamily(
@@ -5911,13 +6010,23 @@ Status ReactiveVersionSet::Recover(
      Version* v = new Version(cfd, this, file_options_,
                               *cfd->GetLatestMutableCFOptions(),
                               current_version_number_++);
-      builder->SaveTo(v->storage_info());
+      s = builder->SaveTo(v->storage_info());

-      // Install recovered version
-      v->PrepareApply(*cfd->GetLatestMutableCFOptions(),
-                      !(db_options_->skip_stats_update_on_db_open));
-      AppendVersion(cfd, v);
+      if (s.ok()) {
+        // Install recovered version
+        v->PrepareApply(*cfd->GetLatestMutableCFOptions(),
+                        !(db_options_->skip_stats_update_on_db_open));
+        AppendVersion(cfd, v);
+      } else {
+        ROCKS_LOG_ERROR(db_options_->info_log,
+                        "[%s]: inconsistent version: %s\n",
+                        cfd->GetName().c_str(), s.ToString().c_str());
+        delete v;
+        break;
+      }
    }
+  }
+  if (s.ok()) {
    next_file_number_.store(version_edit.next_file_number_ + 1);
    last_allocated_sequence_ = version_edit.last_sequence_;
    last_published_sequence_ = version_edit.last_sequence_;
@@ -5994,6 +6103,8 @@ Status ReactiveVersionSet::ReadAndApply(
        s = ApplyOneVersionEditToBuilder(edit, cfds_changed, &temp_edit);
        if (s.ok()) {
          applied_edits++;
+        } else {
+          break;
        }
      }
    }
@@ -6003,13 +6114,14 @@ Status ReactiveVersionSet::ReadAndApply(
    }
    // It's possible that:
    // 1) s.IsCorruption(), indicating the current MANIFEST is corrupted.
+    //    Or the version(s) rebuilt from tailing the MANIFEST is inconsistent.
    // 2) we have finished reading the current MANIFEST.
    // 3) we have encountered an IOError reading the current MANIFEST.
    // We need to look for the next MANIFEST and start from there. If we cannot
    // find the next MANIFEST, we should exit the loop.
-    s = MaybeSwitchManifest(reader->GetReporter(), manifest_reader);
+    Status tmp_s = MaybeSwitchManifest(reader->GetReporter(), manifest_reader);
    reader = manifest_reader->get();
-    if (s.ok()) {
+    if (tmp_s.ok()) {
      if (reader->file()->file_name() == old_manifest_path) {
        // Still processing the same MANIFEST, thus no need to continue this
        // loop since no record is available if we have reached here.
@@ -6039,6 +6151,7 @@ Status ReactiveVersionSet::ReadAndApply(
            number_of_edits_to_skip_ += 2;
          }
        }
+        s = tmp_s;
      }
    }
  }
@@ -6131,12 +6244,16 @@ Status ReactiveVersionSet::ApplyOneVersionEditToBuilder(
      auto version = new Version(cfd, this, file_options_,
                                 *cfd->GetLatestMutableCFOptions(),
                                 current_version_number_++);
-      builder->SaveTo(version->storage_info());
-      version->PrepareApply(*cfd->GetLatestMutableCFOptions(), true);
-      AppendVersion(cfd, version);
-      active_version_builders_.erase(builder_iter);
-      if (cfds_changed->count(cfd) == 0) {
-        cfds_changed->insert(cfd);
+      s = builder->SaveTo(version->storage_info());
+      if (s.ok()) {
+        version->PrepareApply(*cfd->GetLatestMutableCFOptions(), true);
+        AppendVersion(cfd, version);
+        active_version_builders_.erase(builder_iter);
+        if (cfds_changed->count(cfd) == 0) {
+          cfds_changed->insert(cfd);
+        }
+      } else {
+        delete version;
      }
    } else if (s.IsPathNotFound()) {
      s = Status::OK();
@@ -6144,23 +6261,25 @@ Status ReactiveVersionSet::ApplyOneVersionEditToBuilder(
    // Some other error has occurred during LoadTableHandlers.
  }

-  if (version_edit->HasNextFile()) {
-    next_file_number_.store(version_edit->next_file_number_ + 1);
+  if (s.ok()) {
+    if (version_edit->HasNextFile()) {
+      next_file_number_.store(version_edit->next_file_number_ + 1);
+    }
+    if (version_edit->has_last_sequence_) {
+      last_allocated_sequence_ = version_edit->last_sequence_;
+      last_published_sequence_ = version_edit->last_sequence_;
+      last_sequence_ = version_edit->last_sequence_;
+    }
+    if (version_edit->has_prev_log_number_) {
+      prev_log_number_ = version_edit->prev_log_number_;
+      MarkFileNumberUsed(version_edit->prev_log_number_);
+    }
+    if (version_edit->has_log_number_) {
+      MarkFileNumberUsed(version_edit->log_number_);
+    }
+    column_family_set_->UpdateMaxColumnFamily(version_edit->max_column_family_);
+    MarkMinLogNumberToKeep2PC(version_edit->min_log_number_to_keep_);
  }
-  if (version_edit->has_last_sequence_) {
-    last_allocated_sequence_ = version_edit->last_sequence_;
-    last_published_sequence_ = version_edit->last_sequence_;
-    last_sequence_ = version_edit->last_sequence_;
-  }
-  if (version_edit->has_prev_log_number_) {
-    prev_log_number_ = version_edit->prev_log_number_;
-    MarkFileNumberUsed(version_edit->prev_log_number_);
-  }
-  if (version_edit->has_log_number_) {
-    MarkFileNumberUsed(version_edit->log_number_);
-  }
-  column_family_set_->UpdateMaxColumnFamily(version_edit->max_column_family_);
-  MarkMinLogNumberToKeep2PC(version_edit->min_log_number_to_keep_);
  return s;
 }

@@ -573,11 +573,13 @@ class Version {
  // REQUIRES: This version has been saved (see VersionSet::SaveTo)
  void AddIterators(const ReadOptions&, const FileOptions& soptions,
                    MergeIteratorBuilder* merger_iter_builder,
-                    RangeDelAggregator* range_del_agg);
+                    RangeDelAggregator* range_del_agg,
+                    bool allow_unprepared_value);

  void AddIteratorsForLevel(const ReadOptions&, const FileOptions& soptions,
                            MergeIteratorBuilder* merger_iter_builder,
-                            int level, RangeDelAggregator* range_del_agg);
+                            int level, RangeDelAggregator* range_del_agg,
+                            bool allow_unprepared_value);

  Status OverlapWithLevelIterator(const ReadOptions&, const FileOptions&,
                                  const Slice& smallest_user_key,
@@ -627,8 +629,10 @@ class Version {
  // and return true. Otherwise, return false.
  bool Unref();

-  // Add all files listed in the current version to *live.
-  void AddLiveFiles(std::vector<FileDescriptor>* live);
+  // Add all files listed in the current version to *live_table_files and
+  // *live_blob_files.
+  void AddLiveFiles(std::vector<uint64_t>* live_table_files,
+                    std::vector<uint64_t>* live_blob_files) const;

  // Return a human readable string that describes this version's contents.
  std::string DebugString(bool hex = false, bool print_stats = false) const;
@@ -787,6 +791,19 @@ struct ObsoleteFileInfo {
  }
 };

+class ObsoleteBlobFileInfo {
+ public:
+  ObsoleteBlobFileInfo(uint64_t blob_file_number, std::string path)
+      : blob_file_number_(blob_file_number), path_(std::move(path)) {}
+
+  uint64_t GetBlobFileNumber() const { return blob_file_number_; }
+  const std::string& GetPath() const { return path_; }
+
+ private:
+  uint64_t blob_file_number_;
+  std::string path_;
+};
+
 class BaseReferencedVersionBuilder;

 class AtomicGroupReadBuffer {
@@ -1032,8 +1049,10 @@ class VersionSet {
      const Compaction* c, RangeDelAggregator* range_del_agg,
      const FileOptions& file_options_compactions);

-  // Add all files listed in any live version to *live.
-  void AddLiveFiles(std::vector<FileDescriptor>* live_list);
+  // Add all files listed in any live version to *live_table_files and
+  // *live_blob_files. Note that these lists may contain duplicates.
+  void AddLiveFiles(std::vector<uint64_t>* live_table_files,
+                    std::vector<uint64_t>* live_blob_files) const;

  // Return the approximate size of data to be scanned for range [start, end)
  // in levels [start_level, end_level). If end_level == -1 it will search
@@ -1058,7 +1077,12 @@ class VersionSet {
  // This function doesn't support leveldb SST filenames
  void GetLiveFilesMetaData(std::vector<LiveFileMetaData> *metadata);

+  void AddObsoleteBlobFile(uint64_t blob_file_number, std::string path) {
+    obsolete_blob_files_.emplace_back(blob_file_number, std::move(path));
+  }
+
  void GetObsoleteFiles(std::vector<ObsoleteFileInfo>* files,
+                        std::vector<ObsoleteBlobFileInfo>* blob_files,
                        std::vector<std::string>* manifest_filenames,
                        uint64_t min_pending_output);

@@ -1192,6 +1216,7 @@ class VersionSet {
  uint64_t manifest_file_size_;

  std::vector<ObsoleteFileInfo> obsolete_files_;
+  std::vector<ObsoleteBlobFileInfo> obsolete_blob_files_;
  std::vector<std::string> obsolete_manifests_;

  // env options for all reads and writes except compactions
@@ -96,7 +96,7 @@ Options GetOptionsWithNumLevels(int num_levels,
  return opt;
 }

-class VersionStorageInfoTest : public testing::Test {
+class VersionStorageInfoTestBase : public testing::Test {
 public:
  const Comparator* ucmp_;
  InternalKeyComparator icmp_;
@@ -111,17 +111,19 @@ class VersionStorageInfoTest : public testing::Test {
    return InternalKey(ukey, smallest_seq, kTypeValue);
  }

-  VersionStorageInfoTest()
-      : ucmp_(BytewiseComparator()),
+  explicit VersionStorageInfoTestBase(const Comparator* ucmp)
+      : ucmp_(ucmp),
        icmp_(ucmp_),
        logger_(new CountingLogger()),
        options_(GetOptionsWithNumLevels(6, logger_)),
        ioptions_(options_),
        mutable_cf_options_(options_),
-        vstorage_(&icmp_, ucmp_, 6, kCompactionStyleLevel, nullptr, false) {}
+        vstorage_(&icmp_, ucmp_, 6, kCompactionStyleLevel,
+                  /*src_vstorage=*/nullptr,
+                  /*_force_consistency_checks=*/false) {}

-  ~VersionStorageInfoTest() override {
-    for (int i = 0; i < vstorage_.num_levels(); i++) {
+  ~VersionStorageInfoTestBase() override {
+    for (int i = 0; i < vstorage_.num_levels(); ++i) {
      for (auto* f : vstorage_.LevelFiles(i)) {
        if (--f->refs == 0) {
          delete f;
@@ -172,6 +174,13 @@ class VersionStorageInfoTest : public testing::Test {
  }
 };

+class VersionStorageInfoTest : public VersionStorageInfoTestBase {
+ public:
+  VersionStorageInfoTest() : VersionStorageInfoTestBase(BytewiseComparator()) {}
+
+  ~VersionStorageInfoTest() override {}
+};
+
 TEST_F(VersionStorageInfoTest, MaxBytesForLevelStatic) {
  ioptions_.level_compaction_dynamic_level_bytes = false;
  mutable_cf_options_.max_bytes_for_level_base = 10;
@@ -412,6 +421,54 @@ TEST_F(VersionStorageInfoTest, GetOverlappingInputs) {
      1, {"i", 0, kTypeValue}, {"j", 0, kTypeValue}));
 }

+class VersionStorageInfoTimestampTest : public VersionStorageInfoTestBase {
+ public:
+  VersionStorageInfoTimestampTest()
+      : VersionStorageInfoTestBase(test::ComparatorWithU64Ts()) {}
+  ~VersionStorageInfoTimestampTest() override {}
+  std::string Timestamp(uint64_t ts) const {
+    std::string ret;
+    PutFixed64(&ret, ts);
+    return ret;
+  }
+  std::string PackUserKeyAndTimestamp(const Slice& ukey, uint64_t ts) const {
+    std::string ret;
+    ret.assign(ukey.data(), ukey.size());
+    PutFixed64(&ret, ts);
+    return ret;
+  }
+};
+
+TEST_F(VersionStorageInfoTimestampTest, GetOverlappingInputs) {
+  Add(/*level=*/1, /*file_number=*/1, /*smallest=*/
+      {PackUserKeyAndTimestamp("a", /*ts=*/9), /*s=*/0, kTypeValue},
+      /*largest=*/
+      {PackUserKeyAndTimestamp("a", /*ts=*/8), /*s=*/0, kTypeValue},
+      /*file_size=*/100);
+  Add(/*level=*/1, /*file_number=*/2, /*smallest=*/
+      {PackUserKeyAndTimestamp("a", /*ts=*/5), /*s=*/0, kTypeValue},
+      /*largest=*/
+      {PackUserKeyAndTimestamp("b", /*ts=*/10), /*s=*/0, kTypeValue},
+      /*file_size=*/100);
+  Add(/*level=*/1, /*file_number=*/3, /*smallest=*/
+      {PackUserKeyAndTimestamp("c", /*ts=*/12), /*s=*/0, kTypeValue},
+      /*largest=*/
+      {PackUserKeyAndTimestamp("d", /*ts=*/1), /*s=*/0, kTypeValue},
+      /*file_size=*/100);
+  vstorage_.UpdateNumNonEmptyLevels();
+  vstorage_.GenerateLevelFilesBrief();
+  ASSERT_EQ(
+      "1,2",
+      GetOverlappingFiles(
+          /*level=*/1,
+          {PackUserKeyAndTimestamp("a", /*ts=*/12), /*s=*/0, kTypeValue},
+          {PackUserKeyAndTimestamp("a", /*ts=*/11), /*s=*/0, kTypeValue}));
+  ASSERT_EQ("3",
+            GetOverlappingFiles(
+                /*level=*/1,
+                {PackUserKeyAndTimestamp("c", /*ts=*/15), /*s=*/0, kTypeValue},
+                {PackUserKeyAndTimestamp("c", /*ts=*/2), /*s=*/0, kTypeValue}));
+}

 class FindLevelFileTest : public testing::Test {
 public:
@@ -827,6 +884,242 @@ TEST_F(VersionSetTest, SameColumnFamilyGroupCommit) {
  EXPECT_EQ(kGroupSize - 1, count);
 }

+TEST_F(VersionSetTest, PersistBlobFileStateInNewManifest) {
+  // Initialize the database and add a couple of blob files, one with some
+  // garbage in it, and one without any garbage.
+  NewDB();
+
+  VersionEdit edit;
+
+  {
+    constexpr uint64_t blob_file_number = 123;
+    constexpr uint64_t total_blob_count = 456;
+    constexpr uint64_t total_blob_bytes = 77777777;
+    constexpr char checksum_method[] = "SHA1";
+    constexpr char checksum_value[] =
+        "bdb7f34a59dfa1592ce7f52e99f98c570c525cbd";
+    constexpr uint64_t garbage_blob_count = 89;
+    constexpr uint64_t garbage_blob_bytes = 1000000;
+
+    edit.AddBlobFile(blob_file_number, total_blob_count, total_blob_bytes,
+                     checksum_method, checksum_value);
+    edit.AddBlobFileGarbage(blob_file_number, garbage_blob_count,
+                            garbage_blob_bytes);
+  }
+
+  {
+    constexpr uint64_t blob_file_number = 234;
+    constexpr uint64_t total_blob_count = 555;
+    constexpr uint64_t total_blob_bytes = 66666;
+    constexpr char checksum_method[] = "CRC32";
+    constexpr char checksum_value[] = "3d87ff57";
+
+    edit.AddBlobFile(blob_file_number, total_blob_count, total_blob_bytes,
+                     checksum_method, checksum_value);
+  }
+
+  assert(versions_);
+  assert(versions_->GetColumnFamilySet());
+
+  mutex_.Lock();
+  Status s =
+      versions_->LogAndApply(versions_->GetColumnFamilySet()->GetDefault(),
+                             mutable_cf_options_, &edit, &mutex_);
+  mutex_.Unlock();
+
+  ASSERT_OK(s);
+
+  // Force the creation of a new manifest file and make sure metadata for
+  // the blob files is re-persisted.
+  size_t addition_encoded = 0;
+  SyncPoint::GetInstance()->SetCallBack(
+      "BlobFileAddition::EncodeTo::CustomFields",
+      [&](void* /* arg */) { ++addition_encoded; });
+
+  size_t garbage_encoded = 0;
+  SyncPoint::GetInstance()->SetCallBack(
+      "BlobFileGarbage::EncodeTo::CustomFields",
+      [&](void* /* arg */) { ++garbage_encoded; });
+  SyncPoint::GetInstance()->EnableProcessing();
+
+  VersionEdit dummy;
+
+  mutex_.Lock();
+  constexpr FSDirectory* db_directory = nullptr;
+  constexpr bool new_descriptor_log = true;
+  s = versions_->LogAndApply(versions_->GetColumnFamilySet()->GetDefault(),
+                             mutable_cf_options_, &dummy, &mutex_, db_directory,
+                             new_descriptor_log);
+  mutex_.Unlock();
+
+  ASSERT_OK(s);
+  ASSERT_EQ(addition_encoded, 2);
+  ASSERT_EQ(garbage_encoded, 1);
+
+  SyncPoint::GetInstance()->DisableProcessing();
+  SyncPoint::GetInstance()->ClearAllCallBacks();
+}
+
+TEST_F(VersionSetTest, AddLiveBlobFiles) {
+  // Initialize the database and add a blob file.
+  NewDB();
+
+  assert(versions_);
+  assert(versions_->GetColumnFamilySet());
+
+  ColumnFamilyData* const cfd = versions_->GetColumnFamilySet()->GetDefault();
+  assert(cfd);
+
+  VersionEdit first;
+
+  constexpr uint64_t first_blob_file_number = 234;
+  constexpr uint64_t first_total_blob_count = 555;
+  constexpr uint64_t first_total_blob_bytes = 66666;
+  constexpr char first_checksum_method[] = "CRC32";
+  constexpr char first_checksum_value[] = "3d87ff57";
+
+  first.AddBlobFile(first_blob_file_number, first_total_blob_count,
+                    first_total_blob_bytes, first_checksum_method,
+                    first_checksum_value);
+
+  mutex_.Lock();
+  Status s = versions_->LogAndApply(cfd, mutable_cf_options_, &first, &mutex_);
+  mutex_.Unlock();
+
+  ASSERT_OK(s);
+
+  // Reference the version so it stays alive even after the following version
+  // edit.
+  Version* const version = cfd->current();
+  assert(version);
+
+  version->Ref();
+
+  // Get live files directly from version.
+  std::vector<uint64_t> version_table_files;
+  std::vector<uint64_t> version_blob_files;
+
+  version->AddLiveFiles(&version_table_files, &version_blob_files);
+
+  ASSERT_EQ(version_blob_files.size(), 1);
+  ASSERT_EQ(version_blob_files[0], first_blob_file_number);
+
+  // Add another blob file.
+  VersionEdit second;
+
+  constexpr uint64_t second_blob_file_number = 456;
+  constexpr uint64_t second_total_blob_count = 100;
+  constexpr uint64_t second_total_blob_bytes = 2000000;
+  constexpr char second_checksum_method[] = "CRC32B";
+  constexpr char second_checksum_value[] = "6dbdf23a";
+  second.AddBlobFile(second_blob_file_number, second_total_blob_count,
+                     second_total_blob_bytes, second_checksum_method,
+                     second_checksum_value);
+
+  mutex_.Lock();
+  s = versions_->LogAndApply(cfd, mutable_cf_options_, &second, &mutex_);
+  mutex_.Unlock();
+
+  ASSERT_OK(s);
+
+  // Get all live files from version set. Note that the result contains
+  // duplicates.
+  std::vector<uint64_t> all_table_files;
+  std::vector<uint64_t> all_blob_files;
+
+  versions_->AddLiveFiles(&all_table_files, &all_blob_files);
+
+  ASSERT_EQ(all_blob_files.size(), 3);
+  ASSERT_EQ(all_blob_files[0], first_blob_file_number);
+  ASSERT_EQ(all_blob_files[1], first_blob_file_number);
+  ASSERT_EQ(all_blob_files[2], second_blob_file_number);
+
+  // Clean up previous version.
+  version->Unref();
+}
+
+TEST_F(VersionSetTest, ObsoleteBlobFile) {
+  // Initialize the database and add a blob file (with no garbage just yet).
+  NewDB();
+
+  VersionEdit addition;
+
+  constexpr uint64_t blob_file_number = 234;
+  constexpr uint64_t total_blob_count = 555;
+  constexpr uint64_t total_blob_bytes = 66666;
+  constexpr char checksum_method[] = "CRC32";
+  constexpr char checksum_value[] = "3d87ff57";
+
+  addition.AddBlobFile(blob_file_number, total_blob_count, total_blob_bytes,
+                       checksum_method, checksum_value);
+
+  assert(versions_);
+  assert(versions_->GetColumnFamilySet());
+
+  mutex_.Lock();
+  Status s =
+      versions_->LogAndApply(versions_->GetColumnFamilySet()->GetDefault(),
+                             mutable_cf_options_, &addition, &mutex_);
+  mutex_.Unlock();
+
+  ASSERT_OK(s);
+
+  // Mark the entire blob file garbage.
+  VersionEdit garbage;
+
+  garbage.AddBlobFileGarbage(blob_file_number, total_blob_count,
+                             total_blob_bytes);
+
+  mutex_.Lock();
+  s = versions_->LogAndApply(versions_->GetColumnFamilySet()->GetDefault(),
+                             mutable_cf_options_, &garbage, &mutex_);
+  mutex_.Unlock();
+
+  ASSERT_OK(s);
+
+  // Make sure blob files from the pending number range are not returned
+  // as obsolete.
+  {
+    std::vector<ObsoleteFileInfo> table_files;
+    std::vector<ObsoleteBlobFileInfo> blob_files;
+    std::vector<std::string> manifest_files;
+    constexpr uint64_t min_pending_output = blob_file_number;
+
+    versions_->GetObsoleteFiles(&table_files, &blob_files, &manifest_files,
+                                min_pending_output);
+
+    ASSERT_TRUE(blob_files.empty());
+  }
+
+  // Make sure the blob file is returned as obsolete if it's not in the pending
+  // range.
+  {
+    std::vector<ObsoleteFileInfo> table_files;
+    std::vector<ObsoleteBlobFileInfo> blob_files;
+    std::vector<std::string> manifest_files;
+    constexpr uint64_t min_pending_output = blob_file_number + 1;
+
+    versions_->GetObsoleteFiles(&table_files, &blob_files, &manifest_files,
+                                min_pending_output);
+
+    ASSERT_EQ(blob_files.size(), 1);
+    ASSERT_EQ(blob_files[0].GetBlobFileNumber(), blob_file_number);
+  }
+
+  // Make sure it's not returned a second time.
+  {
+    std::vector<ObsoleteFileInfo> table_files;
+    std::vector<ObsoleteBlobFileInfo> blob_files;
+    std::vector<std::string> manifest_files;
+    constexpr uint64_t min_pending_output = blob_file_number + 1;
+
+    versions_->GetObsoleteFiles(&table_files, &blob_files, &manifest_files,
+                                min_pending_output);
+
+    ASSERT_TRUE(blob_files.empty());
+  }
+}
+
 class VersionSetAtomicGroupTest : public VersionSetTestBase,
                                  public testing::Test {
 public:
@@ -1155,7 +1448,7 @@ TEST_F(VersionSetAtomicGroupTest,
  // Write the corrupted edits.
  AddNewEditsToLog(kAtomicGroupSize);
  mu.Lock();
-  EXPECT_OK(
+  EXPECT_NOK(
      reactive_versions_->ReadAndApply(&mu, &manifest_reader, &cfds_changed));
  mu.Unlock();
  EXPECT_EQ(edits_[kAtomicGroupSize / 2].DebugString(),
@@ -1205,7 +1498,7 @@ TEST_F(VersionSetAtomicGroupTest,
                                        &manifest_reader_status));
  AddNewEditsToLog(kAtomicGroupSize);
  mu.Lock();
-  EXPECT_OK(
+  EXPECT_NOK(
      reactive_versions_->ReadAndApply(&mu, &manifest_reader, &cfds_changed));
  mu.Unlock();
  EXPECT_EQ(edits_[1].DebugString(),
@@ -334,10 +334,8 @@ Status WalManager::GetSortedWalsOfType(const std::string& path,
  std::sort(
      log_files.begin(), log_files.end(),
      [](const std::unique_ptr<LogFile>& a, const std::unique_ptr<LogFile>& b) {
-        LogFileImpl* a_impl =
-            static_cast_with_check<LogFileImpl, LogFile>(a.get());
-        LogFileImpl* b_impl =
-            static_cast_with_check<LogFileImpl, LogFile>(b.get());
+        LogFileImpl* a_impl = static_cast_with_check<LogFileImpl>(a.get());
+        LogFileImpl* b_impl = static_cast_with_check<LogFileImpl>(b.get());
        return *a_impl < *b_impl;
      });
  return status;
@@ -53,13 +53,13 @@
 #include "db/write_batch_internal.h"
 #include "monitoring/perf_context_imp.h"
 #include "monitoring/statistics.h"
+#include "port/lang.h"
 #include "rocksdb/merge_operator.h"
 #include "util/autovector.h"
 #include "util/cast_util.h"
 #include "util/coding.h"
 #include "util/duplicate_detector.h"
 #include "util/string_util.h"
-#include "util/util.h"

 namespace ROCKSDB_NAMESPACE {

@@ -1281,7 +1281,7 @@ class MemTableInserter : public WriteBatch::Handler {
        ignore_missing_column_families_(ignore_missing_column_families),
        recovering_log_number_(recovering_log_number),
        log_number_ref_(0),
-        db_(static_cast_with_check<DBImpl, DB>(db)),
+        db_(static_cast_with_check<DBImpl>(db)),
        concurrent_memtable_writes_(concurrent_memtable_writes),
        post_info_created_(false),
        has_valid_writes_(has_valid_writes),
@@ -1630,6 +1630,15 @@ class MemTableInserter : public WriteBatch::Handler {
            cfd->ioptions()->table_factory->Name() + " in CF " +
            cfd->GetName());
      }
+      int cmp = cfd->user_comparator()->Compare(begin_key, end_key);
+      if (cmp > 0) {
+        // It's an empty range where endpoints appear mistaken. Don't bother
+        // applying it to the DB, and return an error to the user.
+        return Status::InvalidArgument("end key comes before start key");
+      } else if (cmp == 0) {
+        // It's an empty range. Don't bother applying it to the DB.
+        return Status::OK();
+      }
    }

    auto ret_status =
@@ -13,6 +13,11 @@
 #include <cmath>

 ROCKSDB_NAMESPACE::DbStressEnvWrapper* db_stress_env = nullptr;
+#ifndef NDEBUG
+// If non-null, injects read error at a rate specified by the
+// read_fault_one_in flag
+std::shared_ptr<ROCKSDB_NAMESPACE::FaultInjectionTestFS> fault_fs_guard;
+#endif // NDEBUG
 enum ROCKSDB_NAMESPACE::CompressionType compression_type_e =
    ROCKSDB_NAMESPACE::kSnappyCompression;
 enum ROCKSDB_NAMESPACE::CompressionType bottommost_compression_type_e =
@@ -58,6 +58,9 @@
 #include "rocksdb/utilities/transaction.h"
 #include "rocksdb/utilities/transaction_db.h"
 #include "rocksdb/write_batch.h"
+#ifndef NDEBUG
+#include "test_util/fault_injection_test_fs.h"
+#endif
 #include "util/coding.h"
 #include "util/compression.h"
 #include "util/crc32c.h"
@@ -66,11 +69,8 @@
 #include "util/random.h"
 #include "util/string_util.h"
 #include "utilities/blob_db/blob_db.h"
-// SyncPoint is not supported in Released Windows Mode.
-#if !(defined NDEBUG) || !defined(OS_WIN)
-#include "test_util/sync_point.h"
-#endif  // !(defined NDEBUG) || !defined(OS_WIN)
 #include "test_util/testutil.h"
+#include "test_util/fault_injection_test_env.h"

 #include "utilities/merge_operators.h"

@@ -112,6 +112,7 @@ DECLARE_bool(memtable_whole_key_filtering);
 DECLARE_int32(open_files);
 DECLARE_int64(compressed_cache_size);
 DECLARE_int32(compaction_style);
+DECLARE_int32(num_levels);
 DECLARE_int32(level0_file_num_compaction_trigger);
 DECLARE_int32(level0_slowdown_writes_trigger);
 DECLARE_int32(level0_stop_writes_trigger);
@@ -155,6 +156,7 @@ DECLARE_bool(mmap_read);
 DECLARE_bool(mmap_write);
 DECLARE_bool(use_direct_reads);
 DECLARE_bool(use_direct_io_for_flush_and_compaction);
+DECLARE_bool(mock_direct_io);
 DECLARE_bool(statistics);
 DECLARE_bool(sync);
 DECLARE_bool(use_fsync);
@@ -200,6 +202,7 @@ DECLARE_string(compression_type);
 DECLARE_string(bottommost_compression_type);
 DECLARE_int32(compression_max_dict_bytes);
 DECLARE_int32(compression_zstd_max_train_bytes);
+DECLARE_int32(compression_parallel_threads);
 DECLARE_string(checksum_type);
 DECLARE_string(hdfs);
 DECLARE_string(env_uri);
@@ -215,6 +218,7 @@ DECLARE_bool(use_full_merge_v1);
 DECLARE_int32(sync_wal_one_in);
 DECLARE_bool(avoid_unnecessary_blocking_io);
 DECLARE_bool(write_dbid_to_manifest);
+DECLARE_bool(avoid_flush_during_recovery);
 DECLARE_uint64(max_write_batch_group_size_bytes);
 DECLARE_bool(level_compaction_dynamic_level_bytes);
 DECLARE_int32(verify_checksum_one_in);
@@ -230,6 +234,7 @@ DECLARE_bool(blob_db_enable_gc);
 DECLARE_double(blob_db_gc_cutoff);
 #endif  // !ROCKSDB_LITE
 DECLARE_int32(approximate_size_one_in);
+DECLARE_bool(sync_fault_injection);

 const long KB = 1024;
 const int kRandomValueMaxFactor = 3;
@@ -237,6 +242,9 @@ const int kValueMaxLen = 100;

 // wrapped posix or hdfs environment
 extern ROCKSDB_NAMESPACE::DbStressEnvWrapper* db_stress_env;
+#ifndef NDEBUG
+extern std::shared_ptr<ROCKSDB_NAMESPACE::FaultInjectionTestFS> fault_fs_guard;
+#endif

 extern enum ROCKSDB_NAMESPACE::CompressionType compression_type_e;
 extern enum ROCKSDB_NAMESPACE::CompressionType bottommost_compression_type_e;
@@ -61,6 +61,12 @@ bool RunStressTest(StressTest* stress) {
    stress->InitReadonlyDb(&shared);
  }

+#ifndef NDEBUG
+  if (FLAGS_sync_fault_injection) {
+    fault_fs_guard->SetFilesystemDirectWritable(false);
+  }
+#endif
+
  uint32_t n = shared.GetNumThreads();

  uint64_t now = db_stress_env->NowMicros();
@@ -186,6 +186,9 @@ DEFINE_int64(compressed_cache_size, -1,
 DEFINE_int32(compaction_style, ROCKSDB_NAMESPACE::Options().compaction_style,
             "");

+DEFINE_int32(num_levels, ROCKSDB_NAMESPACE::Options().num_levels,
+             "Number of levels in the DB");
+
 DEFINE_int32(level0_file_num_compaction_trigger,
             ROCKSDB_NAMESPACE::Options().level0_file_num_compaction_trigger,
             "Level0 compaction start trigger");
@@ -395,6 +398,9 @@ DEFINE_bool(use_direct_io_for_flush_and_compaction,
            ROCKSDB_NAMESPACE::Options().use_direct_io_for_flush_and_compaction,
            "Use O_DIRECT for writing data");

+DEFINE_bool(mock_direct_io, false,
+            "Mock direct IO by not using O_DIRECT for direct IO read");
+
 DEFINE_bool(statistics, false, "Create database statistics");

 DEFINE_bool(sync, false, "Sync all writes to disk");
@@ -581,6 +587,9 @@ DEFINE_int32(compression_zstd_max_train_bytes, 0,
             "Maximum size of training data passed to zstd's dictionary "
             "trainer.");

+DEFINE_int32(compression_parallel_threads, 1,
+             "Number of threads for parallel compression.");
+
 DEFINE_string(bottommost_compression_type, "disable",
              "Algorithm to use to compress bottommost level of the database. "
              "\"disable\" means disabling the feature");
@@ -646,6 +655,10 @@ DEFINE_bool(write_dbid_to_manifest,
            ROCKSDB_NAMESPACE::Options().write_dbid_to_manifest,
            "Write DB_ID to manifest");

+DEFINE_bool(avoid_flush_during_recovery,
+            ROCKSDB_NAMESPACE::Options().avoid_flush_during_recovery,
+            "Avoid flush during recovery");
+
 DEFINE_uint64(max_write_batch_group_size_bytes,
              ROCKSDB_NAMESPACE::Options().max_write_batch_group_size_bytes,
              "Max write batch group size");
@@ -671,4 +684,11 @@ DEFINE_int32(continuous_verification_interval, 1000,
 DEFINE_int32(approximate_size_one_in, 64,
             "If non-zero, DB::GetApproximateSizes() will be called against"
             " random key ranges.");
+
+DEFINE_int32(read_fault_one_in, 1000,
+            "On non-zero, enables fault injection on read");
+
+DEFINE_bool(sync_fault_injection, false,
+            "If true, FaultInjectionTestFS will be used for write operations, "
+            " and unsynced data in DB will lost after crash.");
 #endif  // GFLAGS
@@ -14,5 +14,14 @@
 namespace ROCKSDB_NAMESPACE {
 const uint32_t SharedState::UNKNOWN_SENTINEL = 0xfffffffe;
 const uint32_t SharedState::DELETION_SENTINEL = 0xffffffff;
+#if defined(ROCKSDB_SUPPORT_THREAD_LOCAL)
+#if defined(OS_SOLARIS)
+__thread bool SharedState::ignore_read_error;
+#else
+thread_local bool SharedState::ignore_read_error;
+#endif // OS_SOLARIS
+#else
+bool SharedState::ignore_read_error;
+#endif // ROCKSDB_SUPPORT_THREAD_LOCAL
 }  // namespace ROCKSDB_NAMESPACE
 #endif  // GFLAGS
@@ -11,6 +11,10 @@
 #pragma once

 #include "db_stress_tool/db_stress_stat.h"
+// SyncPoint is not supported in Released Windows Mode.
+#if !(defined NDEBUG) || !defined(OS_WIN)
+#include "test_util/sync_point.h"
+#endif  // !(defined NDEBUG) || !defined(OS_WIN)
 #include "util/gflags_compat.h"

 DECLARE_uint64(seed);
@@ -24,6 +28,7 @@ DECLARE_int32(clear_column_family_one_in);
 DECLARE_bool(test_batches_snapshots);
 DECLARE_int32(compaction_thread_pool_adjust_interval);
 DECLARE_int32(continuous_verification_interval);
+DECLARE_int32(read_fault_one_in);

 namespace ROCKSDB_NAMESPACE {
 class StressTest;
@@ -37,6 +42,20 @@ class SharedState {
  // indicates a key should definitely be deleted
  static const uint32_t DELETION_SENTINEL;

+  // Errors when reading filter blocks are ignored, so we use a thread
+  // local variable updated via sync points to keep track of errors injected
+  // while reading filter blocks in order to ignore the Get/MultiGet result
+  // for those calls
+#if defined(ROCKSDB_SUPPORT_THREAD_LOCAL)
+#if defined(OS_SOLARIS)
+  static __thread bool ignore_read_error;
+#else
+  static thread_local bool ignore_read_error;
+#endif // OS_SOLARIS
+#else
+  static bool ignore_read_error;
+#endif // ROCKSDB_SUPPORT_THREAD_LOCAL
+
  SharedState(Env* env, StressTest* stress_test)
      : cv_(&mu_),
        seed_(static_cast<uint32_t>(FLAGS_seed)),
@@ -171,9 +190,23 @@ class SharedState {
      ++num_bg_threads_;
      fprintf(stdout, "Starting continuous_verification_thread\n");
    }
+#ifndef NDEBUG
+    if (FLAGS_read_fault_one_in) {
+      SyncPoint::GetInstance()->SetCallBack("FaultInjectionIgnoreError",
+                                            IgnoreReadErrorCallback);
+      SyncPoint::GetInstance()->EnableProcessing();
+    }
+#endif // NDEBUG
  }

-  ~SharedState() {}
+  ~SharedState() {
+#ifndef NDEBUG
+    if (FLAGS_read_fault_one_in) {
+      SyncPoint::GetInstance()->ClearAllCallBacks();
+      SyncPoint::GetInstance()->DisableProcessing();
+    }
+#endif
+  }

  port::Mutex* GetMutex() { return &mu_; }

@@ -329,6 +362,10 @@ class SharedState {
  }

 private:
+  static void IgnoreReadErrorCallback(void*) {
+    ignore_read_error = true;
+  }
+
  port::Mutex mu_;
  port::CondVar cv_;
  const uint32_t seed_;
@@ -42,6 +42,7 @@ class Stats {
  long range_deletions_;
  long covered_by_range_deletions_;
  long errors_;
+  long verified_errors_;
  long num_compact_files_succeed_;
  long num_compact_files_failed_;
  int next_report_;
@@ -67,6 +68,7 @@ class Stats {
    range_deletions_ = 0;
    covered_by_range_deletions_ = 0;
    errors_ = 0;
+    verified_errors_ = 0;
    bytes_ = 0;
    seconds_ = 0;
    num_compact_files_succeed_ = 0;
@@ -90,6 +92,7 @@ class Stats {
    range_deletions_ += other.range_deletions_;
    covered_by_range_deletions_ = other.covered_by_range_deletions_;
    errors_ += other.errors_;
+    verified_errors_ += other.verified_errors_;
    bytes_ += other.bytes_;
    seconds_ += other.seconds_;
    num_compact_files_succeed_ += other.num_compact_files_succeed_;
@@ -163,6 +166,8 @@ class Stats {

  void AddErrors(long n) { errors_ += n; }

+  void AddVerifiedErrors(long n) { verified_errors_ += n; }
+
  void AddNumCompactFilesSucceed(long n) { num_compact_files_succeed_ += n; }

  void AddNumCompactFilesFailed(long n) { num_compact_files_failed_ += n; }
@@ -502,6 +502,12 @@ void StressTest::OperateDb(ThreadState* thread) {
  const int delRangeBound = delBound + static_cast<int>(FLAGS_delrangepercent);
  const uint64_t ops_per_open = FLAGS_ops_per_thread / (FLAGS_reopen + 1);

+#ifndef NDEBUG
+  if (FLAGS_read_fault_one_in) {
+    fault_fs_guard->SetThreadLocalReadErrorContext(thread->shared->GetSeed(),
+                                            FLAGS_read_fault_one_in);
+  }
+#endif // NDEBUG
  thread->stats.Start();
  for (int open_cnt = 0; open_cnt <= FLAGS_reopen; ++open_cnt) {
    if (thread->shared->HasVerificationFailedYet() ||
@@ -1721,6 +1727,8 @@ void StressTest::PrintEnv() const {
          FLAGS_max_write_batch_group_size_bytes);
  fprintf(stdout, "Use dynamic level         : %d\n",
          static_cast<int>(FLAGS_level_compaction_dynamic_level_bytes));
+  fprintf(stdout, "Read fault one in         : %d\n", FLAGS_read_fault_one_in);
+  fprintf(stdout, "Sync fault injection      : %d\n", FLAGS_sync_fault_injection);

  fprintf(stdout, "------------------------------------------------\n");
 }
@@ -1795,6 +1803,8 @@ void StressTest::Open() {
    options_.compression_opts.max_dict_bytes = FLAGS_compression_max_dict_bytes;
    options_.compression_opts.zstd_max_train_bytes =
        FLAGS_compression_zstd_max_train_bytes;
+    options_.compression_opts.parallel_threads =
+        FLAGS_compression_parallel_threads;
    options_.create_if_missing = true;
    options_.max_manifest_file_size = FLAGS_max_manifest_file_size;
    options_.inplace_update_support = FLAGS_in_place_update;
@@ -1818,6 +1828,7 @@ void StressTest::Open() {
    options_.avoid_unnecessary_blocking_io =
        FLAGS_avoid_unnecessary_blocking_io;
    options_.write_dbid_to_manifest = FLAGS_write_dbid_to_manifest;
+    options_.avoid_flush_during_recovery = FLAGS_avoid_flush_during_recovery;
    options_.max_write_batch_group_size_bytes =
        FLAGS_max_write_batch_group_size_bytes;
    options_.level_compaction_dynamic_level_bytes =
@@ -23,11 +23,15 @@
 #ifdef GFLAGS
 #include "db_stress_tool/db_stress_common.h"
 #include "db_stress_tool/db_stress_driver.h"
+#ifndef NDEBUG
+#include "test_util/fault_injection_test_fs.h"
+#endif

 namespace ROCKSDB_NAMESPACE {
 namespace {
 static std::shared_ptr<ROCKSDB_NAMESPACE::Env> env_guard;
 static std::shared_ptr<ROCKSDB_NAMESPACE::DbStressEnvWrapper> env_wrapper_guard;
+static std::shared_ptr<CompositeEnvWrapper> fault_env_guard;
 }  // namespace

 KeyGenContext key_gen_ctx;
@@ -41,6 +45,10 @@ int db_stress_tool(int argc, char** argv) {
  SanitizeDoubleParam(&FLAGS_memtable_prefix_bloom_size_ratio);
  SanitizeDoubleParam(&FLAGS_max_bytes_for_level_multiplier);

+  if (FLAGS_mock_direct_io) {
+    test::SetupSyncPointsToMockDirectIO();
+  }
+
  if (FLAGS_statistics) {
    dbstats = ROCKSDB_NAMESPACE::CreateDBStatistics();
    if (FLAGS_test_secondary) {
@@ -69,6 +77,19 @@ int db_stress_tool(int argc, char** argv) {
  } else {
    raw_env = Env::Default();
  }
+
+#ifndef NDEBUG
+  if (FLAGS_read_fault_one_in || FLAGS_sync_fault_injection) {
+    FaultInjectionTestFS* fs =
+        new FaultInjectionTestFS(raw_env->GetFileSystem());
+    fault_fs_guard.reset(fs);
+    fault_fs_guard->SetFilesystemDirectWritable(true);
+    fault_env_guard =
+        std::make_shared<CompositeEnvWrapper>(raw_env, fault_fs_guard);
+    raw_env = fault_env_guard.get();
+  }
+#endif
+
  env_wrapper_guard = std::make_shared<DbStressEnvWrapper>(raw_env);
  db_stress_env = env_wrapper_guard.get();

@@ -9,6 +9,9 @@

 #ifdef GFLAGS
 #include "db_stress_tool/db_stress_common.h"
+#ifndef NDEBUG
+#include "test_util/fault_injection_test_fs.h"
+#endif // NDEBUG

 namespace ROCKSDB_NAMESPACE {
 class NonBatchedOpsStressTest : public StressTest {
@@ -144,18 +147,52 @@ class NonBatchedOpsStressTest : public StressTest {
    std::string key_str = Key(rand_keys[0]);
    Slice key = key_str;
    std::string from_db;
+    int error_count = 0;
+
+#ifndef NDEBUG
+    if (fault_fs_guard) {
+      fault_fs_guard->EnableErrorInjection();
+      SharedState::ignore_read_error = false;
+    }
+#endif // NDEBUG
    Status s = db_->Get(read_opts, cfh, key, &from_db);
+#ifndef NDEBUG
+    if (fault_fs_guard) {
+      error_count = fault_fs_guard->GetAndResetErrorCount();
+    }
+#endif // NDEBUG
    if (s.ok()) {
+#ifndef NDEBUG
+      if (fault_fs_guard) {
+        if (error_count && !SharedState::ignore_read_error) {
+          // Grab mutex so multiple thread don't try to print the
+          // stack trace at the same time
+          MutexLock l(thread->shared->GetMutex());
+          fprintf(stderr, "Didn't get expected error from Get\n");
+          fprintf(stderr, "Callstack that injected the fault\n");
+          fault_fs_guard->PrintFaultBacktrace();
+          std::terminate();
+        }
+      }
+#endif // NDEBUG
      // found case
      thread->stats.AddGets(1, 1);
    } else if (s.IsNotFound()) {
      // not found case
      thread->stats.AddGets(1, 0);
    } else {
-      // errors case
-      fprintf(stderr, "TestGet error: %s\n", s.ToString().c_str());
-      thread->stats.AddErrors(1);
+      if (error_count == 0) {
+        // errors case
+        thread->stats.AddErrors(1);
+      } else {
+        thread->stats.AddVerifiedErrors(1);
+      }
    }
+#ifndef NDEBUG
+    if (fault_fs_guard) {
+      fault_fs_guard->DisableErrorInjection();
+    }
+#endif // NDEBUG
    return s;
  }

@@ -171,6 +208,7 @@ class NonBatchedOpsStressTest : public StressTest {
    std::vector<PinnableSlice> values(num_keys);
    std::vector<Status> statuses(num_keys);
    ColumnFamilyHandle* cfh = column_families_[rand_column_families[0]];
+    int error_count = 0;

    // To appease clang analyzer
    const bool use_txn = FLAGS_use_txn;
@@ -231,8 +269,19 @@ class NonBatchedOpsStressTest : public StressTest {
    }

    if (!use_txn) {
+#ifndef NDEBUG
+      if (fault_fs_guard) {
+        fault_fs_guard->EnableErrorInjection();
+        SharedState::ignore_read_error = false;
+      }
+#endif // NDEBUG
      db_->MultiGet(read_opts, cfh, num_keys, keys.data(), values.data(),
                    statuses.data());
+#ifndef NDEBUG
+      if (fault_fs_guard) {
+        error_count = fault_fs_guard->GetAndResetErrorCount();
+      }
+#endif // NDEBUG
    } else {
 #ifndef ROCKSDB_LITE
      txn->MultiGet(read_opts, cfh, num_keys, keys.data(), values.data(),
@@ -241,6 +290,27 @@ class NonBatchedOpsStressTest : public StressTest {
 #endif
    }

+#ifndef NDEBUG
+    if (fault_fs_guard && error_count && !SharedState::ignore_read_error) {
+      int stat_nok = 0;
+      for (const auto& s : statuses) {
+        if (!s.ok() && !s.IsNotFound()) {
+          stat_nok++;
+        }
+      }
+
+      if (stat_nok < error_count) {
+        // Grab mutex so multiple thread don't try to print the
+        // stack trace at the same time
+        MutexLock l(thread->shared->GetMutex());
+        fprintf(stderr, "Didn't get expected error from MultiGet\n");
+        fprintf(stderr, "Callstack that injected the fault\n");
+        fault_fs_guard->PrintFaultBacktrace();
+        std::terminate();
+      }
+    }
+#endif // NDEBUG
+
    for (const auto& s : statuses) {
      if (s.ok()) {
        // found case
@@ -252,11 +322,20 @@ class NonBatchedOpsStressTest : public StressTest {
        // With txn this is sometimes expected.
        thread->stats.AddGets(1, 1);
      } else {
-        // errors case
-        fprintf(stderr, "MultiGet error: %s\n", s.ToString().c_str());
-        thread->stats.AddErrors(1);
+        if (error_count == 0) {
+          // errors case
+          fprintf(stderr, "MultiGet error: %s\n", s.ToString().c_str());
+          thread->stats.AddErrors(1);
+        } else {
+          thread->stats.AddVerifiedErrors(1);
+        }
      }
    }
+#ifndef NDEBUG
+    if (fault_fs_guard) {
+      fault_fs_guard->DisableErrorInjection();
+    }
+#endif // NDEBUG
    return statuses;
  }

@@ -492,6 +492,12 @@ class CompositeEnvWrapper : public Env {
    return file_system_->NewLogger(fname, io_opts, result, &dbg);
  }

+  Status IsDirectory(const std::string& path, bool* is_dir) override {
+    IOOptions io_opts;
+    IODebugContext dbg;
+    return file_system_->IsDirectory(path, io_opts, is_dir, &dbg);
+  }
+
 #if !defined(OS_WIN) && !defined(ROCKSDB_NO_DYNAMIC_EXTENSION)
  Status LoadLibrary(const std::string& lib_name,
                     const std::string& search_path,
@@ -1081,6 +1087,10 @@ class LegacyFileSystemWrapper : public FileSystem {
                        uint64_t* diskfree, IODebugContext* /*dbg*/) override {
    return status_to_io_status(target_->GetFreeSpace(path, diskfree));
  }
+  IOStatus IsDirectory(const std::string& path, const IOOptions& /*options*/,
+                       bool* is_dir, IODebugContext* /*dbg*/) override {
+    return status_to_io_status(target_->IsDirectory(path, is_dir));
+  }

 private:
  Env* target_;
@@ -5,12 +5,14 @@

 #ifndef ROCKSDB_LITE

+#include "rocksdb/env_encryption.h"
+
 #include <algorithm>
 #include <cassert>
 #include <cctype>
 #include <iostream>

-#include "rocksdb/env_encryption.h"
+#include "monitoring/perf_context_imp.h"
 #include "util/aligned_buffer.h"
 #include "util/coding.h"
 #include "util/random.h"
@@ -49,8 +51,12 @@ class EncryptedSequentialFile : public SequentialFile {
    if (!status.ok()) {
      return status;
    }
-    status = stream_->Decrypt(offset_, (char*)result->data(), result->size());
-    offset_ += result->size(); // We've already ready data from disk, so update offset_ even if decryption fails.
+    {
+      PERF_TIMER_GUARD(decrypt_data_nanos);
+      status = stream_->Decrypt(offset_, (char*)result->data(), result->size());
+    }
+    offset_ += result->size();  // We've already ready data from disk, so update
+                                // offset_ even if decryption fails.
    return status;
  }

@@ -98,7 +104,10 @@ class EncryptedSequentialFile : public SequentialFile {
      return status;
    }
    offset_ = offset + result->size();
-    status = stream_->Decrypt(offset, (char*)result->data(), result->size());
+    {
+      PERF_TIMER_GUARD(decrypt_data_nanos);
+      status = stream_->Decrypt(offset, (char*)result->data(), result->size());
+    }
    return status;
  }
 };
@@ -132,7 +141,10 @@ class EncryptedRandomAccessFile : public RandomAccessFile {
    if (!status.ok()) {
      return status;
    }
-    status = stream_->Decrypt(offset, (char*)result->data(), result->size());
+    {
+      PERF_TIMER_GUARD(decrypt_data_nanos);
+      status = stream_->Decrypt(offset, (char*)result->data(), result->size());
+    }
    return status;
  }

@@ -208,7 +220,10 @@ class EncryptedWritableFile : public WritableFileWrapper {
      // so that the next two lines can be replaced with buf.Append().
      memmove(buf.BufferStart(), data.data(), data.size());
      buf.Size(data.size());
-      status = stream_->Encrypt(offset, buf.BufferStart(), buf.CurrentSize());
+      {
+        PERF_TIMER_GUARD(encrypt_data_nanos);
+        status = stream_->Encrypt(offset, buf.BufferStart(), buf.CurrentSize());
+      }
      if (!status.ok()) {
        return status;
      }
@@ -232,7 +247,10 @@ class EncryptedWritableFile : public WritableFileWrapper {
      buf.AllocateNewBuffer(data.size());
      memmove(buf.BufferStart(), data.data(), data.size());
      buf.Size(data.size());
-      status = stream_->Encrypt(offset, buf.BufferStart(), buf.CurrentSize());
+      {
+        PERF_TIMER_GUARD(encrypt_data_nanos);
+        status = stream_->Encrypt(offset, buf.BufferStart(), buf.CurrentSize());
+      }
      if (!status.ok()) {
        return status;
      }
@@ -337,7 +355,10 @@ class EncryptedRandomRWFile : public RandomRWFile {
      buf.AllocateNewBuffer(data.size());
      memmove(buf.BufferStart(), data.data(), data.size());
      buf.Size(data.size());
-      status = stream_->Encrypt(offset, buf.BufferStart(), buf.CurrentSize());
+      {
+        PERF_TIMER_GUARD(encrypt_data_nanos);
+        status = stream_->Encrypt(offset, buf.BufferStart(), buf.CurrentSize());
+      }
      if (!status.ok()) {
        return status;
      }
@@ -358,7 +379,10 @@ class EncryptedRandomRWFile : public RandomRWFile {
    if (!status.ok()) {
      return status;
    }
-    status = stream_->Decrypt(offset, (char*)result->data(), result->size());
+    {
+      PERF_TIMER_GUARD(decrypt_data_nanos);
+      status = stream_->Decrypt(offset, (char*)result->data(), result->size());
+    }
    return status;
  }

@@ -873,9 +897,15 @@ Status CTREncryptionProvider::CreateNewPrefix(const std::string& /*fname*/,
  // Now populate the rest of the prefix, starting from the third block.
  PopulateSecretPrefixPart(prefix + (2 * blockSize), prefixLength - (2 * blockSize), blockSize);

-  // Encrypt the prefix, starting from block 2 (leave block 0, 1 with initial counter & IV unencrypted)
+  // Encrypt the prefix, starting from block 2 (leave block 0, 1 with initial
+  // counter & IV unencrypted)
  CTRCipherStream cipherStream(cipher_, prefixIV.data(), initialCounter);
-  auto status = cipherStream.Encrypt(0, prefix + (2 * blockSize), prefixLength - (2 * blockSize));
+  Status status;
+  {
+    PERF_TIMER_GUARD(encrypt_data_nanos);
+    status = cipherStream.Encrypt(0, prefix + (2 * blockSize),
+                                  prefixLength - (2 * blockSize));
+  }
  if (!status.ok()) {
    return status;
  }
@@ -910,9 +940,15 @@ Status CTREncryptionProvider::CreateCipherStream(
                              ": read attempt would read beyond file bounds");
  }

-  // Decrypt the encrypted part of the prefix, starting from block 2 (block 0, 1 with initial counter & IV are unencrypted)
+  // Decrypt the encrypted part of the prefix, starting from block 2 (block 0, 1
+  // with initial counter & IV are unencrypted)
  CTRCipherStream cipherStream(cipher_, iv.data(), initialCounter);
-  auto status = cipherStream.Decrypt(0, (char*)prefix.data() + (2 * blockSize), prefix.size() - (2 * blockSize));
+  Status status;
+  {
+    PERF_TIMER_GUARD(decrypt_data_nanos);
+    status = cipherStream.Decrypt(0, (char*)prefix.data() + (2 * blockSize),
+                                  prefix.size() - (2 * blockSize));
+  }
  if (!status.ok()) {
    return status;
  }
@@ -609,6 +609,18 @@ Status HdfsEnv::NewLogger(const std::string& fname,
  return Status::OK();
 }

+Status HdfsEnv::IsDirectory(const std::string& path, bool* is_dir) {
+  hdfsFileInfo* pFileInfo = hdfsGetPathInfo(fileSys_, path.c_str());
+  if (pFileInfo != nullptr) {
+    if (is_dir != nullptr) {
+      *is_dir = (pFileInfo->mKind == tObjectKindDirectory);
+    }
+    hdfsFreeFileInfo(pFileInfo, 1);
+    return Status::OK();
+  }
+  return IOError(path, errno);
+}
+
 // The factory method for creating an HDFS Env
 Status NewHdfsEnv(Env** hdfs_env, const std::string& fsname) {
  *hdfs_env = new HdfsEnv(fsname);
@@ -1937,7 +1937,13 @@ class TestEnv : public EnvWrapper {
  int close_count;
 };

-class EnvTest : public testing::Test {};
+class EnvTest : public testing::Test {
+ public:
+  EnvTest() : test_directory_(test::PerThreadDBPath("env_test")) {}
+
+ protected:
+  const std::string test_directory_;
+};

 TEST_F(EnvTest, Close) {
  TestEnv* env = new TestEnv();
@@ -2090,6 +2096,31 @@ TEST_F(EnvTest, MultipleCompositeEnv) {
  ASSERT_EQ(env2->GetBackgroundThreads(Env::HIGH), 8);
 }

+TEST_F(EnvTest, IsDirectory) {
+  Status s = Env::Default()->CreateDirIfMissing(test_directory_);
+  ASSERT_OK(s);
+  const std::string test_sub_dir = test_directory_ + "sub1";
+  const std::string test_file_path = test_directory_ + "file1";
+  ASSERT_OK(Env::Default()->CreateDirIfMissing(test_sub_dir));
+  bool is_dir = false;
+  ASSERT_OK(Env::Default()->IsDirectory(test_sub_dir, &is_dir));
+  ASSERT_TRUE(is_dir);
+  {
+    std::unique_ptr<FSWritableFile> wfile;
+    s = Env::Default()->GetFileSystem()->NewWritableFile(
+        test_file_path, FileOptions(), &wfile, /*dbg=*/nullptr);
+    ASSERT_OK(s);
+    std::unique_ptr<WritableFileWriter> fwriter;
+    fwriter.reset(new WritableFileWriter(std::move(wfile), test_file_path,
+                                         FileOptions(), Env::Default()));
+    constexpr char buf[] = "test";
+    s = fwriter->Append(buf);
+    ASSERT_OK(s);
+  }
+  ASSERT_OK(Env::Default()->IsDirectory(test_file_path, &is_dir));
+  ASSERT_FALSE(is_dir);
+}
+
 }  // namespace ROCKSDB_NAMESPACE

 int main(int argc, char** argv) {
@@ -122,6 +122,8 @@ int cloexec_flags(int flags, const EnvOptions* options) {
  if (options == nullptr || options->set_fd_cloexec) {
    flags |= O_CLOEXEC;
  }
+#else
+  (void)options;
 #endif
  return flags;
 }
@@ -875,6 +877,28 @@ class PosixFileSystem : public FileSystem {
    return IOStatus::OK();
  }

+  IOStatus IsDirectory(const std::string& path, const IOOptions& /*opts*/,
+                       bool* is_dir, IODebugContext* /*dbg*/) override {
+    // First open
+    int fd = -1;
+    int flags = cloexec_flags(O_RDONLY, nullptr);
+    {
+      IOSTATS_TIMER_GUARD(open_nanos);
+      fd = open(path.c_str(), flags);
+    }
+    if (fd < 0) {
+      return IOError("While open for IsDirectory()", path, errno);
+    }
+    struct stat sbuf;
+    if (fstat(fd, &sbuf) < 0) {
+      return IOError("While doing stat for IsDirectory()", path, errno);
+    }
+    if (nullptr != is_dir) {
+      *is_dir = S_ISDIR(sbuf.st_mode);
+    }
+    return IOStatus::OK();
+  }
+
  FileOptions OptimizeForLogWrite(const FileOptions& file_options,
                                 const DBOptions& db_options) const override {
    FileOptions optimized = file_options;
@@ -608,6 +608,14 @@ IOStatus PosixRandomAccessFile::MultiRead(FSReadRequest* reqs,
                                          size_t num_reqs,
                                          const IOOptions& options,
                                          IODebugContext* dbg) {
+  if (use_direct_io()) {
+    for (size_t i = 0; i < num_reqs; i++) {
+      assert(IsSectorAligned(reqs[i].offset, GetRequiredBufferAlignment()));
+      assert(IsSectorAligned(reqs[i].len, GetRequiredBufferAlignment()));
+      assert(IsSectorAligned(reqs[i].scratch, GetRequiredBufferAlignment()));
+    }
+  }
+
 #if defined(ROCKSDB_IOURING_PRESENT)
  struct io_uring* iu = nullptr;
  if (thread_local_io_urings_) {