make statistics ToString function empty instead of pure virtual

Summary: as title Test Plan: make release Reviewers: yhchiang, sdong Reviewed By: sdong Subscribers: leveldb Differential Revision: https://reviews.facebook.net/D21549
Merge pull request #228 from miguelportilla/develop
2026-11-06 11:02:36 -05:00 · 2014-08-11 15:04:41 -07:00 · 2014-08-11 11:10:23 -07:00 · 2014-08-11 10:47:52 -07:00 · 2014-08-11 13:22:47 -04:00 · 2014-08-08 17:37:03 -07:00
286 changed files with 26166 additions and 5984 deletions
@@ -19,6 +19,7 @@ build_config.mk
 *.*jnilib*
 *.d-e
 *.o-*
+*.swp

 ldb
 manifest_dump
@@ -31,3 +32,4 @@ coverage/COVERAGE_REPORT
 tags
 java/*.log
 java/include/org_rocksdb_*.h
+unity.cc
@@ -0,0 +1,20 @@
+language: cpp
+compiler: gcc
+before_install:
+# As of this writing (10 May 2014) the Travis build environment is Ubuntu 12.04,
+# which needs the following ugly dependency incantations to build RocksDB:
+ - sudo add-apt-repository -y ppa:ubuntu-toolchain-r/test
+ - sudo apt-get update -qq
+ - sudo apt-get install -y -qq gcc-4.8 g++-4.8 zlib1g-dev libbz2-dev libsnappy-dev libjemalloc-dev
+ - sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-4.8 50
+ - sudo update-alternatives --install /usr/bin/g++ g++ /usr/bin/g++-4.8 50
+ - wget https://gflags.googlecode.com/files/libgflags0_2.0-1_amd64.deb
+ - sudo dpkg -i libgflags0_2.0-1_amd64.deb
+ - wget https://gflags.googlecode.com/files/libgflags-dev_2.0-1_amd64.deb
+ - sudo dpkg -i libgflags-dev_2.0-1_amd64.deb
+# Lousy hack to disable use and testing of fallocate, which doesn't behave quite
+# as EnvPosixTest::AllocateTest expects within the Travis OpenVZ environment.
+ - sed -i "s/fallocate(/HACK_NO_fallocate(/" build_tools/build_detect_platform
+script: make check -j8
+notifications:
+    email: false
@@ -10,9 +10,8 @@ the CLA and we can cross-check with your GitHub username.

 Complete your CLA here: <https://code.facebook.com/cla>

-If you don't have a Facebook account, we can send you a PDF that you can
-sign offline. Send us an e-mail or create a new github issue to
-request the CLA in PDF format.
+If you prefer to sign a paper copy, we can send you a PDF.  Send us an 
+e-mail or create a new github issue to request the CLA in PDF format.

 ## License

@@ -1,10 +1,63 @@
 # Rocksdb Change Log

+### Unreleased
+### New Features
+* Support Multiple DB paths in universal style compactions
+* Add feature of storing plain table index and bloom filter in SST file.
+* CompactRange() will never output compacted files to level 0. This used to be the case when all the compaction input files were at level 0.
+
+### Public API changes
+* DBOptions.db_paths now is a vector of a DBPath structure which indicates both of path and target size
+* NewPlainTableFactory instead of bunch of parameters now accepts PlainTableOptions, which is defined in include/rocksdb/table.h
+* Moved include/utilities/*.h to include/rocksdb/utilities/*.h
+* Statistics APIs now take uint32_t as type instead of Tickers. Also make two access functions getTickerCount and histogramData const
+* Add DB property rocksdb.estimate-num-keys, estimated number of live keys in DB.
+* Add DB::GetIntProperty(), which returns DB properties that are integer as uint64_t.
+
+## 3.3.0 (7/10/2014)
+### New Features
+* Added JSON API prototype.
+* HashLinklist reduces performance outlier caused by skewed bucket by switching data in the bucket from linked list to skip list. Add parameter threshold_use_skiplist in NewHashLinkListRepFactory().
+* RocksDB is now able to reclaim storage space more effectively during the compaction process.  This is done by compensating the size of each deletion entry by the 2X average value size, which makes compaction to be triggerred by deletion entries more easily.
+* Add TimeOut API to write.  Now WriteOptions have a variable called timeout_hint_us.  With timeout_hint_us set to non-zero, any write associated with this timeout_hint_us may be aborted when it runs longer than the specified timeout_hint_us, and it is guaranteed that any write completes earlier than the specified time-out will not be aborted due to the time-out condition.
+* Add a rate_limiter option, which controls total throughput of flush and compaction. The throughput is specified in bytes/sec. Flush always has precedence over compaction when available bandwidth is constrained.
+
+### Public API changes
+* Removed NewTotalOrderPlainTableFactory because it is not used and implemented semantically incorrect.
+
+## 3.2.0 (06/20/2014)
+
+### Public API changes
+* We removed seek compaction as a concept from RocksDB because:
+1) It makes more sense for spinning disk workloads, while RocksDB is primarily designed for flash and memory,
+2) It added some complexity to the important code-paths,
+3) None of our internal customers were really using it.
+Because of that, Options::disable_seek_compaction is now obsolete. It is still a parameter in Options, so it does not break the build, but it does not have any effect. We plan to completely remove it at some point, so we ask users to please remove this option from your code base.
+* Add two paramters to NewHashLinkListRepFactory() for logging on too many entries in a hash bucket when flushing.
+* Added new option BlockBasedTableOptions::hash_index_allow_collision. When enabled, prefix hash index for block-based table will not store prefix and allow hash collision, reducing memory consumption.
+
+### New Features
+* PlainTable now supports a new key encoding: for keys of the same prefix, the prefix is only written once. It can be enabled through encoding_type paramter of NewPlainTableFactory()
+* Add AdaptiveTableFactory, which is used to convert from a DB of PlainTable to BlockBasedTabe, or vise versa. It can be created using NewAdaptiveTableFactory()
+
+### Performance Improvements
+* Tailing Iterator re-implemeted with ForwardIterator + Cascading Search Hint , see ~20% throughput improvement.
+
+## 3.1.0 (05/21/2014)
+
+### Public API changes
+* Replaced ColumnFamilyOptions::table_properties_collectors with ColumnFamilyOptions::table_properties_collector_factories
+
+### New Features
+* Hash index for block-based table will be materialized and reconstructed more efficiently. Previously hash index is constructed by scanning the whole table during every table open.
+* FIFO compaction style
+
 ## 3.0.0 (05/05/2014)

 ### Public API changes
 * Added _LEVEL to all InfoLogLevel enums
 * Deprecated ReadOptions.prefix and ReadOptions.prefix_seek. Seek() defaults to prefix-based seek when Options.prefix_extractor is supplied. More detail is documented in https://github.com/facebook/rocksdb/wiki/Prefix-Seek-API-Changes
+* MemTableRepFactory::CreateMemTableRep() takes info logger as an extra parameter.

 ### New Features
 * Column family support
@@ -1,19 +1,32 @@
+## Compilation
+
+RocksDB's library should be able to compile without any dependency installed,
+although we recommend installing some compression libraries (see below).
+We do depend on newer gcc with C++11 support.
+
+There are few options when compiling RocksDB:
+
+* [recommended] `make static_lib` will compile librocksdb.a, RocksDB static library.
+
+* `make shared_lib` will compile librocksdb.so, RocksDB shared library.
+
+* `make check` will compile and run all the unit tests
+
+* `make all` will compile our static library, and all our tools and unit tests. Our tools
+depend on gflags. You will need to have gflags installed to run `make all`.
+
 ## Dependencies

-RocksDB is developed on Linux (CentOS release 5.2), with gcc 4.8.1.
-It depends on gcc with C++11 support.
-
-* RocksDB depends on the following libraries:
+* You can link RocksDB with following compression libraries:
  - [zlib](http://www.zlib.net/) - a library for data compression.
  - [bzip2](http://www.bzip.org/) - a library for data compression.
  - [snappy](https://code.google.com/p/snappy/) - a library for fast
      data compression.
-  - [gflags](https://code.google.com/p/gflags/) - a library that handles
-      command line flags processing.

-RocksDB will successfully compile without the compression libraries included,
-but some things may fail. We do not support releases without the compression
-libraries. You are on your own.
+* All our tools depend on:
+  - [gflags](https://code.google.com/p/gflags/) - a library that handles
+      command line flags processing. You can compile rocksdb library even
+      if you don't have gflags installed.

 ## Supported platforms

@@ -61,7 +74,7 @@ libraries. You are on your own.
            * run `brew tap homebrew/dupes; brew install gcc47 --use-llvm` to install gcc 4.7 (or higher).
    * Install zlib, bzip2 and snappy libraries for compression.
    * Install gflags. We have included a script
-    `build_tools/mac-install-gflags.sh`, which should automatically install it.
+    `build_tools/mac-install-gflags.sh`, which should automatically install it (execute this file instead of runing using "source" command).
    If you installed gflags by other means (for example, `brew install gflags`),
    please set `LIBRARY_PATH` and `CPATH` accordingly.
    * Please note that some of the optimizations/features are disabled in OSX.
@@ -69,12 +82,3 @@ libraries. You are on your own.

 * **iOS**:
  * Run: `TARGET_OS=IOS make static_lib`
-
-## Compilation
-`make clean; make` will compile librocksdb.a (RocksDB static library) and all
-the unit tests. You can run all unit tests with `make check`.
-
-For shared library builds, exec `make shared_lib` instead.
-
-If you followed the above steps and your compile or unit tests fail,
-please submit an issue: (https://github.com/facebook/rocksdb/issues)
@@ -14,19 +14,17 @@ else
 endif

 ifeq ($(MAKECMDGOALS),shared_lib)
-PLATFORM_SHARED_LDFLAGS=-fPIC
 OPT += -DNDEBUG
 endif

 ifeq ($(MAKECMDGOALS),static_lib)
-PLATFORM_SHARED_LDFLAGS=-fPIC
 OPT += -DNDEBUG
 endif

 #-----------------------------------------------

 # detect what platform we're building on
-$(shell (export ROCKSDB_ROOT=$(CURDIR); $(CURDIR)/build_tools/build_detect_platform $(CURDIR)/build_config.mk))
+$(shell (export ROCKSDB_ROOT="$(CURDIR)"; "$(CURDIR)/build_tools/build_detect_platform" "$(CURDIR)/build_config.mk"))
 # this file is generated by the previous line to set build flags and sources
 include build_config.mk

@@ -51,7 +49,7 @@ else
 	PLATFORM_CCFLAGS += $(JEMALLOC_INCLUDE) -DHAVE_JEMALLOC
 endif

-WARNING_FLAGS = -Wall -Werror
+WARNING_FLAGS = -Wall -Werror -Wsign-compare
 CFLAGS += $(WARNING_FLAGS) -I. -I./include $(PLATFORM_CCFLAGS) $(OPT)
 CXXFLAGS += $(WARNING_FLAGS) -I. -I./include $(PLATFORM_CXXFLAGS) $(OPT) -Woverloaded-virtual

@@ -71,6 +69,7 @@ VALGRIND_OPTS = --error-exitcode=$(VALGRIND_ERROR) --leak-check=full

 TESTS = \
 	db_test \
+	db_iter_test \
 	block_hash_index_test \
 	autovector_test \
 	column_family_test \
@@ -106,6 +105,9 @@ TESTS = \
 	stringappend_test \
 	ttl_test \
 	backupable_db_test \
+	document_db_test \
+	json_document_test \
+	spatial_db_test \
 	version_edit_test \
 	version_set_test \
 	file_indexer_test \
@@ -113,7 +115,11 @@ TESTS = \
 	deletefile_test \
 	table_test \
 	thread_local_test \
-        geodb_test
+	geodb_test \
+ 	rate_limiter_test \
+	cuckoo_table_builder_test \
+	options_test \
+	cuckoo_table_reader_test

 TOOLS = \
        sst_dump \
@@ -121,6 +127,7 @@ TOOLS = \
        db_stress \
        ldb \
 	db_repl_stress \
+  options_test \
 	blob_store_bench

 PROGRAMS = db_bench signal_test table_reader_bench log_and_apply_bench $(TOOLS)
@@ -148,7 +155,7 @@ SHARED = $(SHARED1)
 else
 # Update db.h if you change these.
 SHARED_MAJOR = 3
-SHARED_MINOR = 0
+SHARED_MINOR = 4
 SHARED1 = ${LIBNAME}.$(PLATFORM_SHARED_EXT)
 SHARED2 = $(SHARED1).$(SHARED_MAJOR)
 SHARED3 = $(SHARED1).$(SHARED_MAJOR).$(SHARED_MINOR)
@@ -181,10 +188,6 @@ release:
 	$(MAKE) clean
 	OPT="-DNDEBUG -O2" $(MAKE) static_lib $(PROGRAMS) -j32

-release_shared_lib:
-	$(MAKE) clean
-	OPT="-DNDEBUG -O2" $(MAKE) shared_lib -j32
-
 coverage:
 	$(MAKE) clean
 	COVERAGEFLAGS="-fprofile-arcs -ftest-coverage" LDFLAGS+="-lgcov" $(MAKE) all check -j32
@@ -192,11 +195,11 @@ coverage:
 	# Delete intermediate files
 	find . -type f -regex ".*\.\(\(gcda\)\|\(gcno\)\)" -exec rm {} \;

-check: $(PROGRAMS) $(TESTS) $(TOOLS)
+check: $(TESTS) ldb
 	for t in $(TESTS); do echo "***** Running $$t"; ./$$t || exit 1; done
 	python tools/ldb_test.py

-ldb_tests: all $(PROGRAMS) $(TESTS) $(TOOLS)
+ldb_tests: ldb
 	python tools/ldb_test.py

 crash_test: whitebox_crash_test blackbox_crash_test
@@ -231,8 +234,14 @@ valgrind_check: all $(PROGRAMS) $(TESTS)
 		echo $$t $$((etime - stime)) >> $(VALGRIND_DIR)/valgrind_tests_times; \
 	done

+unity.cc:	
+	$(shell (export ROCKSDB_ROOT="$(CURDIR)"; "$(CURDIR)/build_tools/unity" "$(CURDIR)/unity.cc"))
+
+unity: unity.cc unity.o
+	$(CXX) unity.o $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)
+
 clean:
-	-rm -f $(PROGRAMS) $(TESTS) $(LIBRARY) $(SHARED) $(MEMENVLIBRARY) build_config.mk
+	-rm -f $(PROGRAMS) $(TESTS) $(LIBRARY) $(SHARED) $(MEMENVLIBRARY) build_config.mk unity.cc
 	-rm -rf ios-x86/* ios-arm/*
 	-find . -name "*.[od]" -exec rm {} \;
 	-find . -type f -regex ".*\.\(\(gcda\)\|\(gcno\)\)" -exec rm {} \;
@@ -325,6 +334,9 @@ crc32c_test: util/crc32c_test.o $(LIBOBJECTS) $(TESTHARNESS)
 db_test: db/db_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(CXX) db/db_test.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)

+db_iter_test: db/db_iter_test.o $(LIBOBJECTS) $(TESTHARNESS)
+	$(CXX) db/db_iter_test.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)
+
 log_write_bench: util/log_write_bench.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(CXX) util/log_write_bench.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS) -pg

@@ -349,6 +361,15 @@ prefix_test: db/prefix_test.o $(LIBOBJECTS) $(TESTHARNESS)
 backupable_db_test: utilities/backupable/backupable_db_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(CXX) utilities/backupable/backupable_db_test.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@  $(LDFLAGS) $(COVERAGEFLAGS)

+document_db_test: utilities/document/document_db_test.o $(LIBOBJECTS) $(TESTHARNESS)
+	$(CXX) utilities/document/document_db_test.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@  $(LDFLAGS) $(COVERAGEFLAGS)
+
+json_document_test: utilities/document/json_document_test.o $(LIBOBJECTS) $(TESTHARNESS)
+	$(CXX) utilities/document/json_document_test.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@  $(LDFLAGS) $(COVERAGEFLAGS)
+
+spatial_db_test: utilities/spatialdb/spatial_db_test.o $(LIBOBJECTS) $(TESTHARNESS)
+	$(CXX) utilities/spatialdb/spatial_db_test.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@  $(LDFLAGS) $(COVERAGEFLAGS)
+
 ttl_test: utilities/ttl/ttl_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(CXX) utilities/ttl/ttl_test.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@  $(LDFLAGS) $(COVERAGEFLAGS)

@@ -358,6 +379,9 @@ dbformat_test: db/dbformat_test.o $(LIBOBJECTS) $(TESTHARNESS)
 env_test: util/env_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(CXX) util/env_test.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)

+rate_limiter_test: util/rate_limiter_test.o $(LIBOBJECTS) $(TESTHARNESS)
+	$(CXX) util/rate_limiter_test.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)
+
 filename_test: db/filename_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(CXX) db/filename_test.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)

@@ -400,6 +424,15 @@ deletefile_test: db/deletefile_test.o $(LIBOBJECTS) $(TESTHARNESS)
 geodb_test: utilities/geodb/geodb_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(CXX) utilities/geodb/geodb_test.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)

+cuckoo_table_builder_test: table/cuckoo_table_builder_test.o $(LIBOBJECTS) $(TESTHARNESS)
+	$(CXX) table/cuckoo_table_builder_test.o  $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)
+
+cuckoo_table_reader_test: table/cuckoo_table_reader_test.o $(LIBOBJECTS) $(TESTHARNESS) $(BENCHHARNESS)
+	$(CXX) table/cuckoo_table_reader_test.o  $(LIBOBJECTS) $(TESTHARNESS) $(BENCHHARNESS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)
+
+options_test: util/options_test.o $(LIBOBJECTS) $(TESTHARNESS)
+	$(CXX) util/options_test.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)
+
 $(MEMENVLIBRARY) : $(MEMENVOBJECTS)
 	rm -f $@
 	$(AR) -rs $@ $(MEMENVOBJECTS)
@@ -434,18 +467,20 @@ ldb: tools/ldb.o $(LIBOBJECTS)

 JNI_NATIVE_SOURCES = ./java/rocksjni/*.cc
 JAVA_INCLUDE = -I$(JAVA_HOME)/include/ -I$(JAVA_HOME)/include/linux
-ROCKSDBJNILIB = ./java/librocksdbjni.so
+ROCKSDBJNILIB = librocksdbjni.so
+ROCKSDB_JAR = rocksdbjni.jar

 ifeq ($(PLATFORM), OS_MACOSX)
-ROCKSDBJNILIB = ./java/librocksdbjni.jnilib
+ROCKSDBJNILIB = librocksdbjni.jnilib
 JAVA_INCLUDE = -I/System/Library/Frameworks/JavaVM.framework/Headers/
 endif

-rocksdbjava: clean
+rocksdbjava:
 	OPT="-fPIC -DNDEBUG -O2" $(MAKE) $(LIBRARY) -j32
 	cd java;$(MAKE) java;
-	rm -f $(ROCKSDBJNILIB)
-	$(CXX) $(CXXFLAGS) -I./java/. $(JAVA_INCLUDE) -shared -fPIC -o $(ROCKSDBJNILIB) $(JNI_NATIVE_SOURCES) $(LIBOBJECTS) $(LDFLAGS) $(COVERAGEFLAGS)
+	rm -f ./java/$(ROCKSDBJNILIB)
+	$(CXX) $(CXXFLAGS) -I./java/. $(JAVA_INCLUDE) -shared -fPIC -o ./java/$(ROCKSDBJNILIB) $(JNI_NATIVE_SOURCES) $(LIBOBJECTS) $(JAVA_LDFLAGS) $(COVERAGEFLAGS)
+	cd java;jar -cf $(ROCKSDB_JAR) org/rocksdb/*.class org/rocksdb/util/*.class HISTORY*.md $(ROCKSDBJNILIB)

 jclean:
 	cd java;$(MAKE) clean;
@@ -1,82 +0,0 @@
-rocksdb: A persistent key-value store for flash storage
-Authors: * The Facebook Database Engineering Team
-         * Build on earlier work on leveldb by Sanjay Ghemawat
-           (sanjay@google.com) and Jeff Dean (jeff@google.com)
-
-This code is a library that forms the core building block for a fast
-key value server, especially suited for storing data on flash drives.
-It has an Log-Structured-Merge-Database (LSM) design with flexible tradeoffs
-between Write-Amplification-Factor(WAF), Read-Amplification-Factor (RAF)
-and Space-Amplification-Factor(SAF). It has multi-threaded compactions,
-making it specially suitable for storing multiple terabytes of data in a
-single database.
-
-The core of this code has been derived from open-source leveldb.
-
-The code under this directory implements a system for maintaining a
-persistent key/value store.
-
-See doc/index.html and github wiki (https://github.com/facebook/rocksdb/wiki)
-for more explanation.
-
-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.
-
-Guide to header files:
-
-include/rocksdb/db.h
-    Main interface to the DB: Start here
-
-include/rocksdb/options.h
-    Control over the behavior of an entire database, and also
-    control over the behavior of individual reads and writes.
-
-include/rocksdb/comparator.h
-    Abstraction for user-specified comparison function.  If you want
-    just bytewise comparison of keys, you can use the default comparator,
-    but clients can write their own comparator implementations if they
-    want custom ordering (e.g. to handle different character
-    encodings, etc.)
-
-include/rocksdb/iterator.h
-    Interface for iterating over data. You can get an iterator
-    from a DB object.
-
-include/rocksdb/write_batch.h
-    Interface for atomically applying multiple updates to a database.
-
-include/rocksdb/slice.h
-    A simple module for maintaining a pointer and a length into some
-    other byte array.
-
-include/rocksdb/status.h
-    Status is returned from many of the public interfaces and is used
-    to report success and various kinds of errors.
-
-include/rocksdb/env.h
-    Abstraction of the OS environment.  A posix implementation of
-    this interface is in util/env_posix.cc
-
-include/rocksdb/table_builder.h
-    Lower-level modules that most clients probably won't use directly
-
-include/rocksdb/cache.h
-    An API for the block cache.
-
-include/rocksdb/compaction_filter.h
-    An API for a application filter invoked on every compaction.
-
-include/rocksdb/filter_policy.h
-    An API for configuring a bloom filter.
-
-include/rocksdb/memtablerep.h
-    An API for implementing a memtable.
-
-include/rocksdb/statistics.h
-    An API to retrieve various database statistics.
-
-include/rocksdb/transaction_log.h
-    An API to retrieve transaction logs from a database.
-
-Design discussions are conducted in https://www.facebook.com/groups/rocksdb.dev/
@@ -0,0 +1,25 @@
+## RocksDB: A Persistent Key-Value Store for Flash and RAM Storage
+
+[![Build Status](https://travis-ci.org/facebook/rocksdb.svg?branch=master)](https://travis-ci.org/facebook/rocksdb)
+
+RocksDB is developed and maintained by Facebook Database Engineering Team.
+It is built on on earlier work on LevelDB by Sanjay Ghemawat (sanjay@google.com)
+and Jeff Dean (jeff@google.com)
+
+This code is a library that forms the core building block for a fast
+key value server, especially suited for storing data on flash drives.
+It has a Log-Structured-Merge-Database (LSM) design with flexible tradeoffs
+between Write-Amplification-Factor (WAF), Read-Amplification-Factor (RAF)
+and Space-Amplification-Factor (SAF). It has multi-threaded compactions,
+making it specially suitable for storing multiple terabytes of data in a
+single database.
+
+Start with example usage here: https://github.com/facebook/rocksdb/tree/master/examples
+
+See the [github wiki](https://github.com/facebook/rocksdb/wiki) for more explanation.
+
+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/
@@ -7,6 +7,7 @@
 #   CC                          C Compiler path
 #   CXX                         C++ Compiler path
 #   PLATFORM_LDFLAGS            Linker flags
+#   JAVA_LDFLAGS                Linker flags for RocksDBJava
 #   PLATFORM_SHARED_EXT         Extension for shared libraries
 #   PLATFORM_SHARED_LDFLAGS     Flags for building shared library
 #   PLATFORM_SHARED_CFLAGS      Flags for compiling objects for shared library
@@ -21,6 +22,7 @@
 #       -DLEVELDB_PLATFORM_NOATOMIC if it is not
 #       -DSNAPPY                    if the Snappy library is present
 #       -DLZ4                       if the LZ4 library is present
+#       -DNUMA                      if the NUMA library is present
 #
 # Using gflags in rocksdb:
 # Our project depends on gflags, which requires users to take some extra steps
@@ -50,18 +52,18 @@ if [ -d /mnt/gvfs/third-party -a -z "$CXX" ]; then
        CENTOS_VERSION=`rpm -q --qf "%{VERSION}" \
          $(rpm -q --whatprovides redhat-release)`
        if [ "$CENTOS_VERSION" = "6" ]; then
-          source $PWD/build_tools/fbcode.gcc481.sh
+          source "$PWD/build_tools/fbcode.gcc481.sh"
        else
-          source $PWD/build_tools/fbcode.gcc471.sh
+          source "$PWD/build_tools/fbcode.gcc471.sh"
        fi
    else
-        source $PWD/build_tools/fbcode.clang31.sh
+        source "$PWD/build_tools/fbcode.clang31.sh"
    fi
 fi

 # Delete existing output, if it exists
-rm -f $OUTPUT
-touch $OUTPUT
+rm -f "$OUTPUT"
+touch "$OUTPUT"

 if test -z "$CC"; then
   CC=cc
@@ -87,7 +89,7 @@ PLATFORM_SHARED_CFLAGS="-fPIC"
 PLATFORM_SHARED_VERSIONED=false

 # generic port files (working on all platform by #ifdef) go directly in /port
-GENERIC_PORT_FILES=`cd $ROCKSDB_ROOT; find port -name '*.cc' | tr "\n" " "`
+GENERIC_PORT_FILES=`cd "$ROCKSDB_ROOT"; find port -name '*.cc' | tr "\n" " "`

 # On GCC, we pick libc's memcmp over GCC's memcmp via -fno-builtin-memcmp
 case "$TARGET_OS" in
@@ -156,8 +158,10 @@ case "$TARGET_OS" in
        exit 1
 esac

+JAVA_LDFLAGS="$PLATFORM_LDFLAGS"
+
 if test -z "$DO_NOT_RUN_BUILD_DETECT_VERSION"; then
-  $PWD/build_tools/build_detect_version
+  "$PWD/build_tools/build_detect_version"
 fi

 # We want to make a list of all cc files within util, db, table, and helpers
@@ -169,27 +173,21 @@ DIRS="util db table utilities"
 set -f # temporarily disable globbing so that our patterns arent expanded
 PRUNE_TEST="-name *test*.cc -prune"
 PRUNE_BENCH="-name *bench*.cc -prune"
-PORTABLE_FILES=`cd $ROCKSDB_ROOT; find $DIRS $PRUNE_TEST -o $PRUNE_BENCH -o -name '*.cc' -print | sort | tr "\n" " "`
-PORTABLE_CPP=`cd $ROCKSDB_ROOT; find $DIRS $PRUNE_TEST -o $PRUNE_BENCH -o -name '*.cpp' -print | sort | tr "\n" " "`
+PORTABLE_FILES=`cd "$ROCKSDB_ROOT"; find $DIRS $PRUNE_TEST -o $PRUNE_BENCH -o -name '*.cc' -print | sort | tr "\n" " "`
+PORTABLE_CPP=`cd "$ROCKSDB_ROOT"; find $DIRS $PRUNE_TEST -o $PRUNE_BENCH -o -name '*.cpp' -print | sort | tr "\n" " "`
 set +f # re-enable globbing

 # The sources consist of the portable files, plus the platform-specific port
 # file.
-echo "SOURCES=$PORTABLE_FILES $GENERIC_PORT_FILES $PORT_FILES" >> $OUTPUT
-echo "SOURCESCPP=$PORTABLE_CPP" >> $OUTPUT
-echo "MEMENV_SOURCES=helpers/memenv/memenv.cc" >> $OUTPUT
+echo "SOURCES=$PORTABLE_FILES $GENERIC_PORT_FILES $PORT_FILES" >> "$OUTPUT"
+echo "SOURCESCPP=$PORTABLE_CPP" >> "$OUTPUT"
+echo "MEMENV_SOURCES=helpers/memenv/memenv.cc" >> "$OUTPUT"

 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
    true
 else
-    # do fPIC on 64 bit in non-fbcode environment
-    case "$TARGET_OS" in
-        x86_64)
-            PLATFORM_CXXFLAGS="$PLATFORM_CXXFLAGS -fPIC"
-    esac
-
    # If -std=c++0x works, use <atomic>.  Otherwise use port_posix.h.
    $CXX $CFLAGS -std=c++0x -x c++ - -o /dev/null 2>/dev/null  <<EOF
      #include <atomic>
@@ -220,17 +218,31 @@ EOF
    if [ "$?" = 0 ]; then
        COMMON_FLAGS="$COMMON_FLAGS -DSNAPPY"
        PLATFORM_LDFLAGS="$PLATFORM_LDFLAGS -lsnappy"
+        JAVA_LDFLAGS="$JAVA_LDFLAGS -lsnappy"
    fi


    # Test whether gflags library is installed
    # http://code.google.com/p/gflags/
+    # check if the namespace is gflags
    $CXX $CFLAGS -x c++ - -o /dev/null 2>/dev/null  <<EOF
      #include <gflags/gflags.h>
+      using namespace gflags;
      int main() {}
 EOF
    if [ "$?" = 0 ]; then
-        COMMON_FLAGS="$COMMON_FLAGS -DGFLAGS"
+        COMMON_FLAGS="$COMMON_FLAGS -DGFLAGS=gflags"
+        PLATFORM_LDFLAGS="$PLATFORM_LDFLAGS -lgflags"
+    fi
+
+    # check if namespace is google
+    $CXX $CFLAGS -x c++ - -o /dev/null 2>/dev/null  <<EOF
+      #include <gflags/gflags.h>
+      using namespace google;
+      int main() {}
+EOF
+    if [ "$?" = 0 ]; then
+        COMMON_FLAGS="$COMMON_FLAGS -DGFLAGS=google"
        PLATFORM_LDFLAGS="$PLATFORM_LDFLAGS -lgflags"
    fi

@@ -242,6 +254,7 @@ EOF
    if [ "$?" = 0 ]; then
        COMMON_FLAGS="$COMMON_FLAGS -DZLIB"
        PLATFORM_LDFLAGS="$PLATFORM_LDFLAGS -lz"
+        JAVA_LDFLAGS="$JAVA_LDFLAGS -lz"
    fi

    # Test whether bzip library is installed
@@ -252,6 +265,7 @@ EOF
    if [ "$?" = 0 ]; then
        COMMON_FLAGS="$COMMON_FLAGS -DBZIP2"
        PLATFORM_LDFLAGS="$PLATFORM_LDFLAGS -lbz2"
+        JAVA_LDFLAGS="$JAVA_LDFLAGS -lbz2"
    fi

    # Test whether lz4 library is installed
@@ -263,6 +277,19 @@ EOF
    if [ "$?" = 0 ]; then
        COMMON_FLAGS="$COMMON_FLAGS -DLZ4"
        PLATFORM_LDFLAGS="$PLATFORM_LDFLAGS -llz4"
+        JAVA_LDFLAGS="$JAVA_LDFLAGS -llz4"
+    fi
+
+    # Test whether numa is available
+    $CXX $CFLAGS -x c++ - -o /dev/null -lnuma 2>/dev/null  <<EOF
+      #include <numa.h>
+      #inlcude <numaif.h>
+      int main() {}
+EOF
+    if [ "$?" = 0 ]; then
+        COMMON_FLAGS="$COMMON_FLAGS -DNUMA"
+        PLATFORM_LDFLAGS="$PLATFORM_LDFLAGS -lnuma"
+        JAVA_LDFLAGS="$JAVA_LDFLAGS -lnuma"
    fi

    # Test whether tcmalloc is available
@@ -271,6 +298,7 @@ EOF
 EOF
    if [ "$?" = 0 ]; then
        PLATFORM_LDFLAGS="$PLATFORM_LDFLAGS -ltcmalloc"
+        JAVA_LDFLAGS="$JAVA_LDFLAGS -ltcmalloc"
    fi
 fi

@@ -282,11 +310,12 @@ if test "$USE_HDFS"; then
    exit 1
  fi
  HDFS_CCFLAGS="$HDFS_CCFLAGS -I$JAVA_HOME/include -I$JAVA_HOME/include/linux -DUSE_HDFS"
-  HDFS_LDFLAGS="$HDFS_LDFLAGS -Wl,--no-whole-archive hdfs/libhdfs.a -L$JAVA_HOME/jre/lib/amd64"
+  HDFS_LDFLAGS="$HDFS_LDFLAGS -Wl,--no-whole-archive -lhdfs -L$JAVA_HOME/jre/lib/amd64"
  HDFS_LDFLAGS="$HDFS_LDFLAGS -L$JAVA_HOME/jre/lib/amd64/server -L$GLIBC_RUNTIME_PATH/lib"
  HDFS_LDFLAGS="$HDFS_LDFLAGS -ldl -lverify -ljava -ljvm"
  COMMON_FLAGS="$COMMON_FLAGS $HDFS_CCFLAGS"
  PLATFORM_LDFLAGS="$PLATFORM_LDFLAGS $HDFS_LDFLAGS"
+  JAVA_LDFLAGS="$JAVA_LDFLAGS $HDFS_LDFLAGS"
 fi

 # if Intel SSE instruction set is supported, set USE_SSE=" -msse -msse4.2 "
@@ -297,17 +326,18 @@ PLATFORM_CXXFLAGS="$PLATFORM_CXXFLAGS $COMMON_FLAGS"

 VALGRIND_VER="$VALGRIND_VER"

-echo "CC=$CC" >> $OUTPUT
-echo "CXX=$CXX" >> $OUTPUT
-echo "PLATFORM=$PLATFORM" >> $OUTPUT
-echo "PLATFORM_LDFLAGS=$PLATFORM_LDFLAGS" >> $OUTPUT
-echo "VALGRIND_VER=$VALGRIND_VER" >> $OUTPUT
-echo "PLATFORM_CCFLAGS=$PLATFORM_CCFLAGS" >> $OUTPUT
-echo "PLATFORM_CXXFLAGS=$PLATFORM_CXXFLAGS" >> $OUTPUT
-echo "PLATFORM_SHARED_CFLAGS=$PLATFORM_SHARED_CFLAGS" >> $OUTPUT
-echo "PLATFORM_SHARED_EXT=$PLATFORM_SHARED_EXT" >> $OUTPUT
-echo "PLATFORM_SHARED_LDFLAGS=$PLATFORM_SHARED_LDFLAGS" >> $OUTPUT
-echo "PLATFORM_SHARED_VERSIONED=$PLATFORM_SHARED_VERSIONED" >> $OUTPUT
-echo "EXEC_LDFLAGS=$EXEC_LDFLAGS" >> $OUTPUT
-echo "JEMALLOC_INCLUDE=$JEMALLOC_INCLUDE" >> $OUTPUT
-echo "JEMALLOC_LIB=$JEMALLOC_LIB" >> $OUTPUT
+echo "CC=$CC" >> "$OUTPUT"
+echo "CXX=$CXX" >> "$OUTPUT"
+echo "PLATFORM=$PLATFORM" >> "$OUTPUT"
+echo "PLATFORM_LDFLAGS=$PLATFORM_LDFLAGS" >> "$OUTPUT"
+echo "JAVA_LDFLAGS=$JAVA_LDFLAGS" >> "$OUTPUT"
+echo "VALGRIND_VER=$VALGRIND_VER" >> "$OUTPUT"
+echo "PLATFORM_CCFLAGS=$PLATFORM_CCFLAGS" >> "$OUTPUT"
+echo "PLATFORM_CXXFLAGS=$PLATFORM_CXXFLAGS" >> "$OUTPUT"
+echo "PLATFORM_SHARED_CFLAGS=$PLATFORM_SHARED_CFLAGS" >> "$OUTPUT"
+echo "PLATFORM_SHARED_EXT=$PLATFORM_SHARED_EXT" >> "$OUTPUT"
+echo "PLATFORM_SHARED_LDFLAGS=$PLATFORM_SHARED_LDFLAGS" >> "$OUTPUT"
+echo "PLATFORM_SHARED_VERSIONED=$PLATFORM_SHARED_VERSIONED" >> "$OUTPUT"
+echo "EXEC_LDFLAGS=$EXEC_LDFLAGS" >> "$OUTPUT"
+echo "JEMALLOC_INCLUDE=$JEMALLOC_INCLUDE" >> "$OUTPUT"
+echo "JEMALLOC_LIB=$JEMALLOC_LIB" >> "$OUTPUT"
@@ -55,7 +55,7 @@ CFLAGS="-B$TOOLCHAIN_EXECUTABLES/binutils/binutils-2.21.1/da39a3e/bin/gold -m64
 CFLAGS+=" -I $TOOLCHAIN_LIB_BASE/jemalloc/$TOOL_JEMALLOC/include -DHAVE_JEMALLOC"
 CFLAGS+=" $LIBGCC_INCLUDE $GLIBC_INCLUDE"
 CFLAGS+=" -DROCKSDB_PLATFORM_POSIX -DROCKSDB_ATOMIC_PRESENT -DROCKSDB_FALLOCATE_PRESENT"
-CFLAGS+=" -DSNAPPY -DGFLAGS -DZLIB -DBZIP2"
+CFLAGS+=" -DSNAPPY -DGFLAGS=google -DZLIB -DBZIP2"

 EXEC_LDFLAGS=" -Wl,--whole-archive $TOOLCHAIN_LIB_BASE/jemalloc/$TOOL_JEMALLOC/lib/libjemalloc.a"
 EXEC_LDFLAGS+=" -Wl,--no-whole-archive $TOOLCHAIN_LIB_BASE/libunwind/libunwind-1.0.1/350336c/lib/libunwind.a"
@@ -55,22 +55,27 @@ GFLAGS_LIBS=" $TOOLCHAIN_LIB_BASE/gflags/gflags-1.6/c3f970a/lib/libgflags.a"
 JEMALLOC_INCLUDE=" -I $TOOLCHAIN_LIB_BASE/jemalloc/jemalloc-3.4.1/4d53c6f/include/"
 JEMALLOC_LIB=" -Wl,--whole-archive $TOOLCHAIN_LIB_BASE/jemalloc/jemalloc-3.4.1/4d53c6f/lib/libjemalloc.a"

+# location of numa
+NUMA_REV=829d10dac0230f99cd7e1778869d2adf3da24b65
+NUMA_INCLUDE=" -I /mnt/gvfs/third-party2/numa/$NUMA_REV/2.0.8/gcc-4.8.1-glibc-2.17/c3f970a/include/"
+NUMA_LIB=" /mnt/gvfs/third-party2/numa/$NUMA_REV/2.0.8/gcc-4.8.1-glibc-2.17/c3f970a/lib/libnuma.a"
+
 # use Intel SSE support for checksum calculations
 export USE_SSE=" -msse -msse4.2 "

 CC="$TOOLCHAIN_EXECUTABLES/gcc/gcc-4.8.1/cc6c9dc/bin/gcc"
-CXX="$TOOLCHAIN_EXECUTABLES/gcc/gcc-4.8.1/cc6c9dc/bin/g++ $JINCLUDE $SNAPPY_INCLUDE $ZLIB_INCLUDE $BZIP_INCLUDE $LZ4_INCLUDE $GFLAGS_INCLUDE"
+CXX="$TOOLCHAIN_EXECUTABLES/gcc/gcc-4.8.1/cc6c9dc/bin/g++ $JINCLUDE $SNAPPY_INCLUDE $ZLIB_INCLUDE $BZIP_INCLUDE $LZ4_INCLUDE $GFLAGS_INCLUDE $NUMA_INCLUDE"
 AR=$TOOLCHAIN_EXECUTABLES/binutils/binutils-2.21.1/da39a3e/bin/ar
 RANLIB=$TOOLCHAIN_EXECUTABLES/binutils/binutils-2.21.1/da39a3e/bin/ranlib

 CFLAGS="-B$TOOLCHAIN_EXECUTABLES/binutils/binutils-2.21.1/da39a3e/bin/gold -m64 -mtune=generic"
 CFLAGS+=" $LIBGCC_INCLUDE $GLIBC_INCLUDE"
 CFLAGS+=" -DROCKSDB_PLATFORM_POSIX -DROCKSDB_ATOMIC_PRESENT -DROCKSDB_FALLOCATE_PRESENT"
-CFLAGS+=" -DSNAPPY -DGFLAGS -DZLIB -DBZIP2 -DLZ4"
+CFLAGS+=" -DSNAPPY -DGFLAGS=google -DZLIB -DBZIP2 -DLZ4 -DNUMA"

 EXEC_LDFLAGS="-Wl,--dynamic-linker,/usr/local/fbcode/gcc-4.8.1-glibc-2.17/lib/ld.so"
 EXEC_LDFLAGS+=" -Wl,--no-whole-archive $TOOLCHAIN_LIB_BASE/libunwind/libunwind-1.0.1/675d945/lib/libunwind.a"
-EXEC_LDFLAGS+=" $HDFSLIB $SNAPPY_LIBS $ZLIB_LIBS $BZIP_LIBS $LZ4_LIBS $GFLAGS_LIBS"
+EXEC_LDFLAGS+=" $HDFSLIB $SNAPPY_LIBS $ZLIB_LIBS $BZIP_LIBS $LZ4_LIBS $GFLAGS_LIBS $NUMA_LIB"

 PLATFORM_LDFLAGS="$LIBGCC_LIBS $GLIBC_LIBS "

@@ -22,4 +22,4 @@ echo ""
 echo "-----------------------------------------------------------------------------"
 echo "|                         Installation Completed                            |"
 echo "-----------------------------------------------------------------------------"
-echo "Please run `. ~/bash_profile` to be able to compile with gflags"
+echo "Please run \`. ~/.bash_profile\` to be able to compile with gflags"
@@ -109,7 +109,6 @@ make release
    --cache_numshardbits=6 \
    --table_cache_numshardbits=4 \
    --open_files=55000 \
-    --disable_seek_compaction=1 \
    --statistics=1 \
    --histogram=1 \
    --disable_data_sync=1 \
@@ -129,7 +128,6 @@ make release
    --cache_numshardbits=6 \
    --table_cache_numshardbits=4 \
    --open_files=55000 \
-    --disable_seek_compaction=1 \
    --use_tailing_iterator=1 \
    --statistics=1 \
    --histogram=1 \
@@ -150,7 +148,6 @@ make release
    --cache_numshardbits=6 \
    --table_cache_numshardbits=4 \
    --open_files=55000 \
-    --disable_seek_compaction=1 \
    --statistics=1 \
    --histogram=1 \
    --disable_data_sync=1 \
@@ -172,7 +169,6 @@ make release
    --table_cache_numshardbits=4 \
    --write_buffer_size=1000000000 \
    --open_files=55000 \
-    --disable_seek_compaction=1 \
    --statistics=1 \
    --histogram=1 \
    --disable_data_sync=1 \
@@ -231,7 +227,6 @@ make release
    --cache_numshardbits=6 \
    --table_cache_numshardbits=4 \
    --open_files=55000 \
-    --disable_seek_compaction=1 \
    --disable_auto_compactions=1 \
    --statistics=1 \
    --histogram=1 \
@@ -254,7 +249,6 @@ make release
    --cache_numshardbits=6 \
    --table_cache_numshardbits=4 \
    --open_files=55000 \
-    --disable_seek_compaction=1 \
    --statistics=1 \
    --histogram=1 \
    --disable_data_sync=1 \
@@ -274,7 +268,6 @@ make release
    --table_cache_numshardbits=4 \
    --write_buffer_size=1000000000 \
    --open_files=55000 \
-    --disable_seek_compaction=1 \
    --statistics=1 \
    --histogram=1 \
    --disable_data_sync=1 \
@@ -283,6 +276,75 @@ make release
    --value_size=10 \
    --threads=16 > ${STAT_FILE}.memtablefillreadrandom

+common_in_mem_args="--db=/dev/shm/rocksdb \
+    --num_levels=6 \
+    --key_size=20 \
+    --prefix_size=12 \
+    --keys_per_prefix=10 \
+    --value_size=100 \
+    --compression_type=none \
+    --compression_ratio=1 \
+    --hard_rate_limit=2 \
+    --write_buffer_size=134217728 \
+    --max_write_buffer_number=4 \
+    --level0_file_num_compaction_trigger=8 \
+    --level0_slowdown_writes_trigger=16 \
+    --level0_stop_writes_trigger=24 \
+    --target_file_size_base=134217728 \
+    --max_bytes_for_level_base=1073741824 \
+    --disable_wal=0 \
+    --wal_dir=/dev/shm/rocksdb \
+    --sync=0 \
+    --disable_data_sync=1 \
+    --verify_checksum=1 \
+    --delete_obsolete_files_period_micros=314572800 \
+    --max_grandparent_overlap_factor=10 \
+    --use_plain_table=1 \
+    --open_files=-1 \
+    --mmap_read=1 \
+    --mmap_write=0 \
+    --memtablerep=prefix_hash \
+    --bloom_bits=10 \
+    --bloom_locality=1 \
+    --perf_level=0"
+
+# prepare a in-memory DB with 50M keys, total DB size is ~6G
+./db_bench \
+    $common_in_mem_args \
+    --statistics=0 \
+    --max_background_compactions=16 \
+    --max_background_flushes=16 \
+    --benchmarks=filluniquerandom \
+    --use_existing_db=0 \
+    --num=52428800 \
+    --threads=1 > /dev/null
+
+# Readwhilewriting
+./db_bench \
+    $common_in_mem_args \
+    --statistics=1 \
+    --max_background_compactions=4 \
+    --max_background_flushes=0 \
+    --benchmarks=readwhilewriting\
+    --use_existing_db=1 \
+    --duration=600 \
+    --threads=32 \
+    --writes_per_second=81920 > ${STAT_FILE}.readwhilewriting_in_ram
+
+# Seekrandomwhilewriting
+./db_bench \
+    $common_in_mem_args \
+    --statistics=1 \
+    --max_background_compactions=4 \
+    --max_background_flushes=0 \
+    --benchmarks=seekrandomwhilewriting \
+    --use_existing_db=1 \
+    --use_tailing_iterator=1 \
+    --duration=600 \
+    --threads=32 \
+    --writes_per_second=81920 > ${STAT_FILE}.seekwhilewriting_in_ram
+
+
 # send data to ods
 function send_to_ods {
  key="$1"
@@ -308,9 +370,9 @@ function send_benchmark_to_ods {
  file="$3"

  QPS=$(grep $bench $file | awk '{print $5}')
-  P50_MICROS=$(grep $bench $file -A 4 | tail -n1 | awk '{print $3}' )
-  P75_MICROS=$(grep $bench $file -A 4 | tail -n1 | awk '{print $5}' )
-  P99_MICROS=$(grep $bench $file -A 4 | tail -n1 | awk '{print $7}' )
+  P50_MICROS=$(grep $bench $file -A 6 | grep "Percentiles" | awk '{print $3}' )
+  P75_MICROS=$(grep $bench $file -A 6 | grep "Percentiles" | awk '{print $5}' )
+  P99_MICROS=$(grep $bench $file -A 6 | grep "Percentiles" | awk '{print $7}' )

  send_to_ods rocksdb.build.$bench_key.qps $QPS
  send_to_ods rocksdb.build.$bench_key.p50_micros $P50_MICROS
@@ -328,3 +390,5 @@ send_benchmark_to_ods readrandom readrandom_fillunique_random $STAT_FILE.readran
 send_benchmark_to_ods fillrandom memtablefillrandom $STAT_FILE.memtablefillreadrandom
 send_benchmark_to_ods readrandom memtablereadrandom $STAT_FILE.memtablefillreadrandom
 send_benchmark_to_ods readwhilewriting readwhilewriting $STAT_FILE.readwhilewriting
+send_benchmark_to_ods readwhilewriting readwhilewriting_in_ram ${STAT_FILE}.readwhilewriting_in_ram
+send_benchmark_to_ods seekrandomwhilewriting seekwhilewriting_in_ram ${STAT_FILE}.seekwhilewriting_in_ram
@@ -0,0 +1,78 @@
+#!/bin/sh
+#
+# Create the unity file
+#
+
+OUTPUT=$1
+if test -z "$OUTPUT"; then
+  echo "usage: $0 <output-filename>" >&2
+  exit 1
+fi
+
+# Delete existing file, if it exists
+rm -f "$OUTPUT"
+touch "$OUTPUT"
+
+# Detect OS
+if test -z "$TARGET_OS"; then
+    TARGET_OS=`uname -s`
+fi
+
+# generic port files (working on all platform by #ifdef) go directly in /port
+GENERIC_PORT_FILES=`cd "$ROCKSDB_ROOT"; find port -name '*.cc' | tr "\n" " "`
+
+# On GCC, we pick libc's memcmp over GCC's memcmp via -fno-builtin-memcmp
+case "$TARGET_OS" in
+    Darwin)
+        # PORT_FILES=port/darwin/darwin_specific.cc
+        ;;
+    IOS)
+        ;;
+    Linux)
+        # PORT_FILES=port/linux/linux_specific.cc
+        ;;
+    SunOS)
+        # PORT_FILES=port/sunos/sunos_specific.cc
+        ;;
+    FreeBSD)
+        # PORT_FILES=port/freebsd/freebsd_specific.cc
+        ;;
+    NetBSD)
+        # PORT_FILES=port/netbsd/netbsd_specific.cc
+        ;;
+    OpenBSD)
+        # PORT_FILES=port/openbsd/openbsd_specific.cc
+        ;;
+    DragonFly)
+        # PORT_FILES=port/dragonfly/dragonfly_specific.cc
+        ;;
+    OS_ANDROID_CROSSCOMPILE)
+        # PORT_FILES=port/android/android.cc
+        ;;
+    *)
+        echo "Unknown platform!" >&2
+        exit 1
+esac
+
+# We want to make a list of all cc files within util, db, table, and helpers
+# except for the test and benchmark files. By default, find will output a list
+# of all files matching either rule, so we need to append -print to make the
+# prune take effect.
+DIRS="util db table utilities"
+
+set -f # temporarily disable globbing so that our patterns arent expanded
+PRUNE_TEST="-name *test*.cc -prune"
+PRUNE_BENCH="-name *bench*.cc -prune"
+PORTABLE_FILES=`cd "$ROCKSDB_ROOT"; find $DIRS $PRUNE_TEST -o $PRUNE_BENCH -o -name '*.cc' -print | sort`
+PORTABLE_CPP=`cd "$ROCKSDB_ROOT"; find $DIRS $PRUNE_TEST -o $PRUNE_BENCH -o -name '*.cpp' -print | sort`
+set +f # re-enable globbing
+
+# The sources consist of the portable files, plus the platform-specific port
+# file.
+for SOURCE_FILE in $PORTABLE_FILES $GENERIC_PORT_FILES $PORT_FILES $PORTABLE_CPP
+do
+	echo "#include <$SOURCE_FILE>" >> "$OUTPUT"
+done
+
+echo "int main(int argc, char** argv){ return 0; }" >> "$OUTPUT"
+
@@ -40,9 +40,10 @@ Status BuildTable(const std::string& dbname, Env* env, const Options& options,
                  const InternalKeyComparator& internal_comparator,
                  const SequenceNumber newest_snapshot,
                  const SequenceNumber earliest_seqno_in_memtable,
-                  const CompressionType compression) {
+                  const CompressionType compression,
+                  const Env::IOPriority io_priority) {
  Status s;
-  meta->file_size = 0;
+  meta->fd.file_size = 0;
  meta->smallest_seqno = meta->largest_seqno = 0;
  iter->SeekToFirst();

@@ -54,13 +55,15 @@ Status BuildTable(const std::string& dbname, Env* env, const Options& options,
    purge = false;
  }

-  std::string fname = TableFileName(dbname, meta->number);
+  std::string fname = TableFileName(options.db_paths, meta->fd.GetNumber(),
+                                    meta->fd.GetPathId());
  if (iter->Valid()) {
    unique_ptr<WritableFile> file;
    s = env->NewWritableFile(fname, &file, soptions);
    if (!s.ok()) {
      return s;
    }
+    file->SetIOPriority(io_priority);

    TableBuilder* builder =
        NewTableBuilder(options, internal_comparator, file.get(), compression);
@@ -110,6 +113,13 @@ Status BuildTable(const std::string& dbname, Env* env, const Options& options,
          is_first_key = false;

          if (this_ikey.type == kTypeMerge) {
+            // TODO(tbd): Add a check here to prevent RocksDB from crash when
+            // reopening a DB w/o properly specifying the merge operator.  But
+            // currently we observed a memory leak on failing in RocksDB
+            // recovery, so we decide to let it crash instead of causing
+            // memory leak for now before we have identified the real cause
+            // of the memory leak.
+
            // Handle merge-type keys using the MergeHelper
            // TODO: pass statistics to MergeUntil
            merge.MergeUntil(iter, 0 /* don't worry about snapshot */);
@@ -177,8 +187,8 @@ Status BuildTable(const std::string& dbname, Env* env, const Options& options,
    if (s.ok()) {
      s = builder->Finish();
      if (s.ok()) {
-        meta->file_size = builder->FileSize();
-        assert(meta->file_size > 0);
+        meta->fd.file_size = builder->FileSize();
+        assert(meta->fd.GetFileSize() > 0);
      }
    } else {
      builder->Abandon();
@@ -202,7 +212,7 @@ Status BuildTable(const std::string& dbname, Env* env, const Options& options,
    if (s.ok()) {
      // Verify that the table is usable
      Iterator* it = table_cache->NewIterator(ReadOptions(), soptions,
-                                              internal_comparator, *meta);
+                                              internal_comparator, meta->fd);
      s = it->status();
      delete it;
    }
@@ -213,7 +223,7 @@ Status BuildTable(const std::string& dbname, Env* env, const Options& options,
    s = iter->status();
  }

-  if (s.ok() && meta->file_size > 0) {
+  if (s.ok() && meta->fd.GetFileSize() > 0) {
    // Keep it
  } else {
    env->DeleteFile(fname);
@@ -7,6 +7,7 @@
 // found in the LICENSE file. See the AUTHORS file for names of contributors.
 #pragma once
 #include "rocksdb/comparator.h"
+#include "rocksdb/env.h"
 #include "rocksdb/status.h"
 #include "rocksdb/types.h"
 #include "rocksdb/options.h"
@@ -29,7 +30,7 @@ extern TableBuilder* NewTableBuilder(
    WritableFile* file, CompressionType compression_type);

 // Build a Table file from the contents of *iter.  The generated file
-// will be named according to meta->number.  On success, the rest of
+// will be named according to number specified in meta. On success, the rest of
 // *meta will be filled with metadata about the generated table.
 // If no data is present in *iter, meta->file_size will be set to
 // zero, and no Table file will be produced.
@@ -40,6 +41,7 @@ extern Status BuildTable(const std::string& dbname, Env* env,
                         const InternalKeyComparator& internal_comparator,
                         const SequenceNumber newest_snapshot,
                         const SequenceNumber earliest_seqno_in_memtable,
-                         const CompressionType compression);
+                         const CompressionType compression,
+                         const Env::IOPriority io_priority = Env::IO_HIGH);

 }  // namespace rocksdb
@@ -14,6 +14,7 @@
 #include <stdlib.h>
 #include <unistd.h>
 #include "rocksdb/cache.h"
+#include "rocksdb/compaction_filter.h"
 #include "rocksdb/comparator.h"
 #include "rocksdb/db.h"
 #include "rocksdb/env.h"
@@ -30,9 +31,19 @@
 #include "rocksdb/table.h"

 using rocksdb::Cache;
+using rocksdb::ColumnFamilyDescriptor;
+using rocksdb::ColumnFamilyHandle;
+using rocksdb::ColumnFamilyOptions;
+using rocksdb::CompactionFilter;
+using rocksdb::CompactionFilterFactory;
+using rocksdb::CompactionFilterV2;
+using rocksdb::CompactionFilterFactoryV2;
+using rocksdb::CompactionFilterContext;
+using rocksdb::CompactionOptionsFIFO;
 using rocksdb::Comparator;
 using rocksdb::CompressionType;
 using rocksdb::DB;
+using rocksdb::DBOptions;
 using rocksdb::Env;
 using rocksdb::InfoLogLevel;
 using rocksdb::FileLock;
@@ -66,6 +77,7 @@ struct rocksdb_iterator_t        { Iterator*         rep; };
 struct rocksdb_writebatch_t      { WriteBatch        rep; };
 struct rocksdb_snapshot_t        { const Snapshot*   rep; };
 struct rocksdb_flushoptions_t    { FlushOptions      rep; };
+struct rocksdb_fifo_compaction_options_t { CompactionOptionsFIFO rep; };
 struct rocksdb_readoptions_t     { ReadOptions       rep; };
 struct rocksdb_writeoptions_t    { WriteOptions      rep; };
 struct rocksdb_options_t         { Options           rep; };
@@ -76,6 +88,172 @@ struct rocksdb_filelock_t        { FileLock*         rep; };
 struct rocksdb_logger_t          { shared_ptr<Logger>  rep; };
 struct rocksdb_cache_t           { shared_ptr<Cache>   rep; };
 struct rocksdb_livefiles_t       { std::vector<LiveFileMetaData> rep; };
+struct rocksdb_column_family_handle_t  { ColumnFamilyHandle* rep; };
+
+struct rocksdb_compactionfiltercontext_t {
+  CompactionFilter::Context rep;
+};
+
+struct rocksdb_compactionfilter_t : public CompactionFilter {
+  void* state_;
+  void (*destructor_)(void*);
+  unsigned char (*filter_)(
+      void*,
+      int level,
+      const char* key, size_t key_length,
+      const char* existing_value, size_t value_length,
+      char** new_value, size_t *new_value_length,
+      unsigned char* value_changed);
+  const char* (*name_)(void*);
+
+  virtual ~rocksdb_compactionfilter_t() {
+    (*destructor_)(state_);
+  }
+
+  virtual bool Filter(
+      int level,
+      const Slice& key,
+      const Slice& existing_value,
+      std::string* new_value,
+      bool* value_changed) const {
+    char* c_new_value = NULL;
+    size_t new_value_length = 0;
+    unsigned char c_value_changed = 0;
+    unsigned char result = (*filter_)(
+        state_,
+        level,
+        key.data(), key.size(),
+        existing_value.data(), existing_value.size(),
+        &c_new_value, &new_value_length, &c_value_changed);
+    if (c_value_changed) {
+      new_value->assign(c_new_value, new_value_length);
+      *value_changed = true;
+    }
+    return result;
+  }
+
+  virtual const char* Name() const {
+    return (*name_)(state_);
+  }
+};
+
+struct rocksdb_compactionfilterfactory_t : public CompactionFilterFactory {
+  void* state_;
+  void (*destructor_)(void*);
+  rocksdb_compactionfilter_t* (*create_compaction_filter_)(
+      void*, rocksdb_compactionfiltercontext_t* context);
+  const char* (*name_)(void*);
+
+  virtual ~rocksdb_compactionfilterfactory_t() { (*destructor_)(state_); }
+
+  virtual std::unique_ptr<CompactionFilter> CreateCompactionFilter(
+      const CompactionFilter::Context& context) {
+    rocksdb_compactionfiltercontext_t ccontext;
+    ccontext.rep = context;
+    CompactionFilter* cf = (*create_compaction_filter_)(state_, &ccontext);
+    return std::unique_ptr<CompactionFilter>(cf);
+  }
+
+  virtual const char* Name() const { return (*name_)(state_); }
+};
+
+struct rocksdb_compactionfilterv2_t : public CompactionFilterV2 {
+  void* state_;
+  void (*destructor_)(void*);
+  const char* (*name_)(void*);
+  void (*filter_)(void*, int level, size_t num_keys,
+                  const char* const* keys_list, const size_t* keys_list_sizes,
+                  const char* const* existing_values_list, const size_t* existing_values_list_sizes,
+                  char** new_values_list, size_t* new_values_list_sizes,
+                  unsigned char* to_delete_list);
+
+  virtual ~rocksdb_compactionfilterv2_t() {
+    (*destructor_)(state_);
+  }
+
+  virtual const char* Name() const {
+    return (*name_)(state_);
+  }
+
+  virtual std::vector<bool> Filter(int level,
+                                   const SliceVector& keys,
+                                   const SliceVector& existing_values,
+                                   std::vector<std::string>* new_values,
+                                   std::vector<bool>* values_changed) const {
+    // Make a vector pointing to the underlying key data.
+    size_t num_keys = keys.size();
+    std::vector<const char*> keys_list(num_keys);
+    std::vector<size_t> keys_list_sizes(num_keys);
+    for (size_t i = 0; i < num_keys; ++i) {
+      keys_list[i] = keys[i].data();
+      keys_list_sizes[i] = keys[i].size();
+    }
+    // Make a vector pointing to the underlying value data.
+    std::vector<const char*> existing_values_list(num_keys);
+    std::vector<size_t> existing_values_list_sizes(num_keys);
+    for (size_t i = 0; i < num_keys; ++i) {
+      existing_values_list[i] = existing_values[i].data();
+      existing_values_list_sizes[i] = existing_values[i].size();
+    }
+    // Make a vector which will accept newly-allocated char* arrays
+    // which we will take ownership of and assign to strings in new_values.
+    new_values->clear();
+    std::vector<char*> new_values_list(num_keys);
+    std::vector<size_t> new_values_list_sizes(num_keys);
+    // Resize values_changed to hold all keys.
+    values_changed->resize(num_keys);
+    // Make a vector for bools indicating a value should be deleted
+    // on compaction (true) or maintained (false).
+    std::vector<unsigned char> to_delete_list(num_keys);
+
+    (*filter_)(
+        state_, level, num_keys, &keys_list[0], &keys_list_sizes[0],
+        &existing_values_list[0], &existing_values_list_sizes[0],
+        &new_values_list[0], &new_values_list_sizes[0], &to_delete_list[0]);
+
+    // Now, we transfer any changed values, setting values_changed and
+    // initializing new_values in the event a value changed.
+    std::vector<bool> to_delete(num_keys);
+    for (size_t i = 0; i < num_keys; ++i) {
+      to_delete[i] = to_delete_list[i];
+      (*values_changed)[i] = new_values_list[i] != nullptr;
+      if ((*values_changed)[i]) {
+        new_values->push_back(std::string(new_values_list[i], new_values_list_sizes[i]));
+        free(new_values_list[i]);
+      }
+    }
+    return to_delete;
+  }
+};
+
+struct rocksdb_compactionfilterfactoryv2_t : public CompactionFilterFactoryV2 {
+  void* state_;
+  void (*destructor_)(void*);
+  const char* (*name_)(void*);
+  rocksdb_compactionfilterv2_t* (*create_compaction_filter_v2_)(
+      void* state, const rocksdb_compactionfiltercontext_t* context);
+
+  rocksdb_compactionfilterfactoryv2_t(const SliceTransform* prefix_extractor)
+      : CompactionFilterFactoryV2(prefix_extractor) {
+  }
+
+  virtual ~rocksdb_compactionfilterfactoryv2_t() {
+    (*destructor_)(state_);
+  }
+
+  virtual const char* Name() const {
+    return (*name_)(state_);
+  }
+
+  virtual std::unique_ptr<CompactionFilterV2> CreateCompactionFilterV2(
+      const CompactionFilterContext& context) {
+    struct rocksdb_compactionfiltercontext_t c_context;
+    c_context.rep.is_full_compaction = context.is_full_compaction;
+    c_context.rep.is_manual_compaction = context.is_manual_compaction;
+    return std::unique_ptr<CompactionFilterV2>(
+        (*create_compaction_filter_v2_)(state_, &c_context));
+  }
+};

 struct rocksdb_comparator_t : public Comparator {
  void* state_;
@@ -349,6 +527,120 @@ void rocksdb_close(rocksdb_t* db) {
  delete db;
 }

+rocksdb_t* rocksdb_open_column_families(
+    const rocksdb_options_t* db_options,
+    const char* name,
+    int num_column_families,
+    const char** column_family_names,
+    const rocksdb_options_t** column_family_options,
+    rocksdb_column_family_handle_t** column_family_handles,
+    char** errptr) {
+  std::vector<ColumnFamilyDescriptor> column_families;
+  for (int i = 0; i < num_column_families; i++) {
+    column_families.push_back(ColumnFamilyDescriptor(
+        std::string(column_family_names[i]),
+        ColumnFamilyOptions(column_family_options[i]->rep)));
+  }
+
+  DB* db;
+  std::vector<ColumnFamilyHandle*> handles;
+  if (SaveError(errptr, DB::Open(DBOptions(db_options->rep),
+          std::string(name), column_families, &handles, &db))) {
+    return nullptr;
+  }
+
+  for (size_t i = 0; i < handles.size(); i++) {
+    rocksdb_column_family_handle_t* c_handle = new rocksdb_column_family_handle_t;
+    c_handle->rep = handles[i];
+    column_family_handles[i] = c_handle;
+  }
+  rocksdb_t* result = new rocksdb_t;
+  result->rep = db;
+  return result;
+}
+
+rocksdb_t* rocksdb_open_for_read_only_column_families(
+    const rocksdb_options_t* db_options,
+    const char* name,
+    int num_column_families,
+    const char** column_family_names,
+    const rocksdb_options_t** column_family_options,
+    rocksdb_column_family_handle_t** column_family_handles,
+    unsigned char error_if_log_file_exist,
+    char** errptr) {
+  std::vector<ColumnFamilyDescriptor> column_families;
+  for (int i = 0; i < num_column_families; i++) {
+    column_families.push_back(ColumnFamilyDescriptor(
+        std::string(column_family_names[i]),
+        ColumnFamilyOptions(column_family_options[i]->rep)));
+  }
+
+  DB* db;
+  std::vector<ColumnFamilyHandle*> handles;
+  if (SaveError(errptr, DB::OpenForReadOnly(DBOptions(db_options->rep),
+          std::string(name), column_families, &handles, &db, error_if_log_file_exist))) {
+    return nullptr;
+  }
+
+  for (size_t i = 0; i < handles.size(); i++) {
+    rocksdb_column_family_handle_t* c_handle = new rocksdb_column_family_handle_t;
+    c_handle->rep = handles[i];
+    column_family_handles[i] = c_handle;
+  }
+  rocksdb_t* result = new rocksdb_t;
+  result->rep = db;
+  return result;
+}
+
+char** rocksdb_list_column_families(
+    const rocksdb_options_t* options,
+    const char* name,
+    size_t* lencfs,
+    char** errptr) {
+  std::vector<std::string> fams;
+  SaveError(errptr,
+      DB::ListColumnFamilies(DBOptions(options->rep),
+        std::string(name), &fams));
+
+  *lencfs = fams.size();
+  char** column_families = static_cast<char**>(malloc(sizeof(char*) * fams.size()));
+  for (size_t i = 0; i < fams.size(); i++) {
+    column_families[i] = strdup(fams[i].c_str());
+  }
+  return column_families;
+}
+
+void rocksdb_list_column_families_destroy(char** list, size_t len) {
+  for (size_t i = 0; i < len; ++i) {
+    free(list[i]);
+  }
+  free(list);
+}
+
+rocksdb_column_family_handle_t* rocksdb_create_column_family(
+    rocksdb_t* db,
+    const rocksdb_options_t* column_family_options,
+    const char* column_family_name,
+    char** errptr) {
+  rocksdb_column_family_handle_t* handle = new rocksdb_column_family_handle_t;
+  SaveError(errptr,
+      db->rep->CreateColumnFamily(ColumnFamilyOptions(column_family_options->rep),
+        std::string(column_family_name), &(handle->rep)));
+  return handle;
+}
+
+void rocksdb_drop_column_family(
+    rocksdb_t* db,
+    rocksdb_column_family_handle_t* handle,
+    char** errptr) {
+  SaveError(errptr, db->rep->DropColumnFamily(handle->rep));
+}
+
+void rocksdb_column_family_handle_destroy(rocksdb_column_family_handle_t* handle) {
+  delete handle->rep;
+  delete handle;
+}
+
 void rocksdb_put(
    rocksdb_t* db,
    const rocksdb_writeoptions_t* options,
@@ -359,6 +651,18 @@ void rocksdb_put(
            db->rep->Put(options->rep, Slice(key, keylen), Slice(val, vallen)));
 }

+void rocksdb_put_cf(
+    rocksdb_t* db,
+    const rocksdb_writeoptions_t* options,
+    rocksdb_column_family_handle_t* column_family,
+    const char* key, size_t keylen,
+    const char* val, size_t vallen,
+    char** errptr) {
+  SaveError(errptr,
+            db->rep->Put(options->rep, column_family->rep,
+              Slice(key, keylen), Slice(val, vallen)));
+}
+
 void rocksdb_delete(
    rocksdb_t* db,
    const rocksdb_writeoptions_t* options,
@@ -367,6 +671,16 @@ void rocksdb_delete(
  SaveError(errptr, db->rep->Delete(options->rep, Slice(key, keylen)));
 }

+void rocksdb_delete_cf(
+    rocksdb_t* db,
+    const rocksdb_writeoptions_t* options,
+    rocksdb_column_family_handle_t* column_family,
+    const char* key, size_t keylen,
+    char** errptr) {
+  SaveError(errptr, db->rep->Delete(options->rep, column_family->rep,
+        Slice(key, keylen)));
+}
+
 void rocksdb_merge(
    rocksdb_t* db,
    const rocksdb_writeoptions_t* options,
@@ -377,6 +691,18 @@ void rocksdb_merge(
            db->rep->Merge(options->rep, Slice(key, keylen), Slice(val, vallen)));
 }

+void rocksdb_merge_cf(
+    rocksdb_t* db,
+    const rocksdb_writeoptions_t* options,
+    rocksdb_column_family_handle_t* column_family,
+    const char* key, size_t keylen,
+    const char* val, size_t vallen,
+    char** errptr) {
+  SaveError(errptr,
+            db->rep->Merge(options->rep, column_family->rep,
+              Slice(key, keylen), Slice(val, vallen)));
+}
+
 void rocksdb_write(
    rocksdb_t* db,
    const rocksdb_writeoptions_t* options,
@@ -406,6 +732,29 @@ char* rocksdb_get(
  return result;
 }

+char* rocksdb_get_cf(
+    rocksdb_t* db,
+    const rocksdb_readoptions_t* options,
+    rocksdb_column_family_handle_t* column_family,
+    const char* key, size_t keylen,
+    size_t* vallen,
+    char** errptr) {
+  char* result = nullptr;
+  std::string tmp;
+  Status s = db->rep->Get(options->rep, column_family->rep,
+      Slice(key, keylen), &tmp);
+  if (s.ok()) {
+    *vallen = tmp.size();
+    result = CopyString(tmp);
+  } else {
+    *vallen = 0;
+    if (!s.IsNotFound()) {
+      SaveError(errptr, s);
+    }
+  }
+  return result;
+}
+
 rocksdb_iterator_t* rocksdb_create_iterator(
    rocksdb_t* db,
    const rocksdb_readoptions_t* options) {
@@ -414,6 +763,15 @@ rocksdb_iterator_t* rocksdb_create_iterator(
  return result;
 }

+rocksdb_iterator_t* rocksdb_create_iterator_cf(
+    rocksdb_t* db,
+    const rocksdb_readoptions_t* options,
+    rocksdb_column_family_handle_t* column_family) {
+  rocksdb_iterator_t* result = new rocksdb_iterator_t;
+  result->rep = db->rep->NewIterator(options->rep, column_family->rep);
+  return result;
+}
+
 const rocksdb_snapshot_t* rocksdb_create_snapshot(
    rocksdb_t* db) {
  rocksdb_snapshot_t* result = new rocksdb_snapshot_t;
@@ -440,6 +798,19 @@ char* rocksdb_property_value(
  }
 }

+char* rocksdb_property_value_cf(
+    rocksdb_t* db,
+    rocksdb_column_family_handle_t* column_family,
+    const char* propname) {
+  std::string tmp;
+  if (db->rep->GetProperty(column_family->rep, Slice(propname), &tmp)) {
+    // We use strdup() since we expect human readable output.
+    return strdup(tmp.c_str());
+  } else {
+    return nullptr;
+  }
+}
+
 void rocksdb_approximate_sizes(
    rocksdb_t* db,
    int num_ranges,
@@ -455,6 +826,22 @@ void rocksdb_approximate_sizes(
  delete[] ranges;
 }

+void rocksdb_approximate_sizes_cf(
+    rocksdb_t* db,
+    rocksdb_column_family_handle_t* column_family,
+    int num_ranges,
+    const char* const* range_start_key, const size_t* range_start_key_len,
+    const char* const* range_limit_key, const size_t* range_limit_key_len,
+    uint64_t* sizes) {
+  Range* ranges = new Range[num_ranges];
+  for (int i = 0; i < num_ranges; i++) {
+    ranges[i].start = Slice(range_start_key[i], range_start_key_len[i]);
+    ranges[i].limit = Slice(range_limit_key[i], range_limit_key_len[i]);
+  }
+  db->rep->GetApproximateSizes(column_family->rep, ranges, num_ranges, sizes);
+  delete[] ranges;
+}
+
 void rocksdb_delete_file(
    rocksdb_t* db,
    const char* name) {
@@ -479,6 +866,19 @@ void rocksdb_compact_range(
      (limit_key ? (b = Slice(limit_key, limit_key_len), &b) : nullptr));
 }

+void rocksdb_compact_range_cf(
+    rocksdb_t* db,
+    rocksdb_column_family_handle_t* column_family,
+    const char* start_key, size_t start_key_len,
+    const char* limit_key, size_t limit_key_len) {
+  Slice a, b;
+  db->rep->CompactRange(
+      column_family->rep,
+      // Pass nullptr Slice if corresponding "const char*" is nullptr
+      (start_key ? (a = Slice(start_key, start_key_len), &a) : nullptr),
+      (limit_key ? (b = Slice(limit_key, limit_key_len), &b) : nullptr));
+}
+
 void rocksdb_flush(
    rocksdb_t* db,
    const rocksdb_flushoptions_t* options,
@@ -562,6 +962,13 @@ rocksdb_writebatch_t* rocksdb_writebatch_create() {
  return new rocksdb_writebatch_t;
 }

+rocksdb_writebatch_t* rocksdb_writebatch_create_from(const char* rep,
+                                                     size_t size) {
+  rocksdb_writebatch_t* b = new rocksdb_writebatch_t;
+  b->rep = WriteBatch(std::string(rep, size));
+  return b;
+}
+
 void rocksdb_writebatch_destroy(rocksdb_writebatch_t* b) {
  delete b;
 }
@@ -581,6 +988,14 @@ void rocksdb_writebatch_put(
  b->rep.Put(Slice(key, klen), Slice(val, vlen));
 }

+void rocksdb_writebatch_put_cf(
+    rocksdb_writebatch_t* b,
+    rocksdb_column_family_handle_t* column_family,
+    const char* key, size_t klen,
+    const char* val, size_t vlen) {
+  b->rep.Put(column_family->rep, Slice(key, klen), Slice(val, vlen));
+}
+
 void rocksdb_writebatch_merge(
    rocksdb_writebatch_t* b,
    const char* key, size_t klen,
@@ -588,12 +1003,27 @@ void rocksdb_writebatch_merge(
  b->rep.Merge(Slice(key, klen), Slice(val, vlen));
 }

+void rocksdb_writebatch_merge_cf(
+    rocksdb_writebatch_t* b,
+    rocksdb_column_family_handle_t* column_family,
+    const char* key, size_t klen,
+    const char* val, size_t vlen) {
+  b->rep.Merge(column_family->rep, Slice(key, klen), Slice(val, vlen));
+}
+
 void rocksdb_writebatch_delete(
    rocksdb_writebatch_t* b,
    const char* key, size_t klen) {
  b->rep.Delete(Slice(key, klen));
 }

+void rocksdb_writebatch_delete_cf(
+    rocksdb_writebatch_t* b,
+    rocksdb_column_family_handle_t* column_family,
+    const char* key, size_t klen) {
+  b->rep.Delete(column_family->rep, Slice(key, klen));
+}
+
 void rocksdb_writebatch_iterate(
    rocksdb_writebatch_t* b,
    void* state,
@@ -631,6 +1061,38 @@ void rocksdb_options_destroy(rocksdb_options_t* options) {
  delete options;
 }

+void rocksdb_options_increase_parallelism(
+    rocksdb_options_t* opt, int total_threads) {
+  opt->rep.IncreaseParallelism(total_threads);
+}
+
+void rocksdb_options_optimize_for_point_lookup(
+    rocksdb_options_t* opt) {
+  opt->rep.OptimizeForPointLookup();
+}
+
+void rocksdb_options_optimize_level_style_compaction(
+    rocksdb_options_t* opt, uint64_t memtable_memory_budget) {
+  opt->rep.OptimizeLevelStyleCompaction(memtable_memory_budget);
+}
+
+void rocksdb_options_optimize_universal_style_compaction(
+    rocksdb_options_t* opt, uint64_t memtable_memory_budget) {
+  opt->rep.OptimizeUniversalStyleCompaction(memtable_memory_budget);
+}
+
+void rocksdb_options_set_compaction_filter(
+    rocksdb_options_t* opt,
+    rocksdb_compactionfilter_t* filter) {
+  opt->rep.compaction_filter = filter;
+}
+
+void rocksdb_options_set_compaction_filter_factory(
+    rocksdb_options_t* opt, rocksdb_compactionfilterfactory_t* factory) {
+  opt->rep.compaction_filter_factory =
+      std::shared_ptr<CompactionFilterFactory>(factory);
+}
+
 void rocksdb_options_set_comparator(
    rocksdb_options_t* opt,
    rocksdb_comparator_t* cmp) {
@@ -643,6 +1105,12 @@ void rocksdb_options_set_merge_operator(
  opt->rep.merge_operator = std::shared_ptr<MergeOperator>(merge_operator);
 }

+void rocksdb_options_set_compaction_filter_factory_v2(
+    rocksdb_options_t* opt,
+    rocksdb_compactionfilterfactoryv2_t* compaction_filter_factory_v2) {
+  opt->rep.compaction_filter_factory_v2 = std::shared_ptr<CompactionFilterFactoryV2>(compaction_filter_factory_v2);
+}
+
 void rocksdb_options_set_filter_policy(
    rocksdb_options_t* opt,
    rocksdb_filterpolicy_t* policy) {
@@ -654,6 +1122,11 @@ void rocksdb_options_set_create_if_missing(
  opt->rep.create_if_missing = v;
 }

+void rocksdb_options_set_create_missing_column_families(
+    rocksdb_options_t* opt, unsigned char v) {
+  opt->rep.create_missing_column_families = v;
+}
+
 void rocksdb_options_set_error_if_exists(
    rocksdb_options_t* opt, unsigned char v) {
  opt->rep.error_if_exists = v;
@@ -1062,9 +1535,13 @@ void rocksdb_options_set_plain_table_factory(
    double hash_table_ratio, size_t index_sparseness) {
  static rocksdb::TableFactory* factory = 0;
  if (!factory) {
-    factory = rocksdb::NewPlainTableFactory(
-        user_key_len, bloom_bits_per_key,
-        hash_table_ratio, index_sparseness);
+    rocksdb::PlainTableOptions options;
+    options.user_key_len = user_key_len;
+    options.bloom_bits_per_key = bloom_bits_per_key;
+    options.hash_table_ratio = hash_table_ratio;
+    options.index_sparseness = index_sparseness;
+
+    factory = rocksdb::NewPlainTableFactory(options);
  }
  opt->rep.table_factory.reset(factory);
 }
@@ -1107,6 +1584,12 @@ void rocksdb_options_set_universal_compaction_options(rocksdb_options_t *opt, ro
  opt->rep.compaction_options_universal = *(uco->rep);
 }

+void rocksdb_options_set_fifo_compaction_options(
+    rocksdb_options_t* opt,
+    rocksdb_fifo_compaction_options_t* fifo) {
+  opt->rep.compaction_options_fifo = fifo->rep;
+}
+
 /*
 TODO:
 DB::OpenForReadOnly
@@ -1119,10 +1602,101 @@ DB::GetUpdatesSince
 DB::GetDbIdentity
 DB::RunManualCompaction
 custom cache
-compaction_filter
 table_properties_collectors
 */

+rocksdb_compactionfilter_t* rocksdb_compactionfilter_create(
+    void* state,
+    void (*destructor)(void*),
+    unsigned char (*filter)(
+        void*,
+        int level,
+        const char* key, size_t key_length,
+        const char* existing_value, size_t value_length,
+        char** new_value, size_t *new_value_length,
+        unsigned char* value_changed),
+    const char* (*name)(void*)) {
+  rocksdb_compactionfilter_t* result = new rocksdb_compactionfilter_t;
+  result->state_ = state;
+  result->destructor_ = destructor;
+  result->filter_ = filter;
+  result->name_ = name;
+  return result;
+}
+
+void rocksdb_compactionfilter_destroy(rocksdb_compactionfilter_t* filter) {
+  delete filter;
+}
+
+unsigned char rocksdb_compactionfiltercontext_is_full_compaction(
+    rocksdb_compactionfiltercontext_t* context) {
+  return context->rep.is_full_compaction;
+}
+
+unsigned char rocksdb_compactionfiltercontext_is_manual_compaction(
+    rocksdb_compactionfiltercontext_t* context) {
+  return context->rep.is_manual_compaction;
+}
+
+rocksdb_compactionfilterfactory_t* rocksdb_compactionfilterfactory_create(
+    void* state, void (*destructor)(void*),
+    rocksdb_compactionfilter_t* (*create_compaction_filter)(
+        void*, rocksdb_compactionfiltercontext_t* context),
+    const char* (*name)(void*)) {
+  rocksdb_compactionfilterfactory_t* result =
+      new rocksdb_compactionfilterfactory_t;
+  result->state_ = state;
+  result->destructor_ = destructor;
+  result->create_compaction_filter_ = create_compaction_filter;
+  result->name_ = name;
+  return result;
+}
+
+void rocksdb_compactionfilterfactory_destroy(
+    rocksdb_compactionfilterfactory_t* factory) {
+  delete factory;
+}
+
+rocksdb_compactionfilterv2_t* rocksdb_compactionfilterv2_create(
+    void* state,
+    void (*destructor)(void*),
+    void (*filter)(void*, int level, size_t num_keys,
+                   const char* const* keys_list, const size_t* keys_list_sizes,
+                   const char* const* existing_values_list, const size_t* existing_values_list_sizes,
+                   char** new_values_list, size_t* new_values_list_sizes,
+                   unsigned char* to_delete_list),
+    const char* (*name)(void*)) {
+  rocksdb_compactionfilterv2_t* result = new rocksdb_compactionfilterv2_t;
+  result->state_ = state;
+  result->destructor_ = destructor;
+  result->filter_ = filter;
+  result->name_ = name;
+  return result;
+}
+
+void rocksdb_compactionfilterv2_destroy(rocksdb_compactionfilterv2_t* filter) {
+  delete filter;
+}
+
+rocksdb_compactionfilterfactoryv2_t* rocksdb_compactionfilterfactoryv2_create(
+    void* state,
+    rocksdb_slicetransform_t* prefix_extractor,
+    void (*destructor)(void*),
+    rocksdb_compactionfilterv2_t* (*create_compaction_filter_v2)(
+        void* state, const rocksdb_compactionfiltercontext_t* context),
+    const char* (*name)(void*)) {
+  rocksdb_compactionfilterfactoryv2_t* result = new rocksdb_compactionfilterfactoryv2_t(prefix_extractor);
+  result->state_ = state;
+  result->destructor_ = destructor;
+  result->create_compaction_filter_v2_ = create_compaction_filter_v2;
+  result->name_ = name;
+  return result;
+}
+
+void rocksdb_compactionfilterfactoryv2_destroy(rocksdb_compactionfilterfactoryv2_t* factory) {
+  delete factory;
+}
+
 rocksdb_comparator_t* rocksdb_comparator_create(
    void* state,
    void (*destructor)(void*),
@@ -1414,6 +1988,22 @@ void rocksdb_universal_compaction_options_destroy(
  delete uco;
 }

+rocksdb_fifo_compaction_options_t* rocksdb_fifo_compaction_options_create() {
+  rocksdb_fifo_compaction_options_t* result = new rocksdb_fifo_compaction_options_t;
+  result->rep =  CompactionOptionsFIFO();
+  return result;
+}
+
+void rocksdb_fifo_compaction_options_set_max_table_files_size(
+    rocksdb_fifo_compaction_options_t* fifo_opts, uint64_t size) {
+  fifo_opts->rep.max_table_files_size = size;
+}
+
+void rocksdb_fifo_compaction_options_destroy(
+    rocksdb_fifo_compaction_options_t* fifo_opts) {
+  delete fifo_opts;
+}
+
 void rocksdb_options_set_min_level_to_compress(rocksdb_options_t* opt, int level) {
  if (level >= 0) {
    assert(level <= opt->rep.num_levels);
@@ -75,6 +75,22 @@ static void CheckGet(
  Free(&val);
 }

+static void CheckGetCF(
+    rocksdb_t* db,
+    const rocksdb_readoptions_t* options,
+    rocksdb_column_family_handle_t* handle,
+    const char* key,
+    const char* expected) {
+  char* err = NULL;
+  size_t val_len;
+  char* val;
+  val = rocksdb_get_cf(db, options, handle, key, strlen(key), &val_len, &err);
+  CheckNoError(err);
+  CheckEqual(expected, val, val_len);
+  Free(&val);
+}
+
+
 static void CheckIter(rocksdb_iterator_t* iter,
                      const char* key, const char* val) {
  size_t len;
@@ -154,6 +170,111 @@ static unsigned char FilterKeyMatch(
  return fake_filter_result;
 }

+// Custom compaction filter
+static void CFilterDestroy(void* arg) {}
+static const char* CFilterName(void* arg) { return "foo"; }
+static unsigned char CFilterFilter(void* arg, int level, const char* key,
+                                   size_t key_length,
+                                   const char* existing_value,
+                                   size_t value_length, char** new_value,
+                                   size_t* new_value_length,
+                                   unsigned char* value_changed) {
+  if (key_length == 3) {
+    if (memcmp(key, "bar", key_length) == 0) {
+      return 1;
+    } else if (memcmp(key, "baz", key_length) == 0) {
+      *value_changed = 1;
+      *new_value = "newbazvalue";
+      *new_value_length = 11;
+      return 0;
+    }
+  }
+  return 0;
+}
+
+static void CFilterFactoryDestroy(void* arg) {}
+static const char* CFilterFactoryName(void* arg) { return "foo"; }
+static rocksdb_compactionfilter_t* CFilterCreate(
+    void* arg, rocksdb_compactionfiltercontext_t* context) {
+  return rocksdb_compactionfilter_create(NULL, CFilterDestroy, CFilterFilter,
+                                         CFilterName);
+}
+
+static rocksdb_t* CheckCompaction(rocksdb_t* db, rocksdb_options_t* options,
+                                  rocksdb_readoptions_t* roptions,
+                                  rocksdb_writeoptions_t* woptions) {
+  char* err = NULL;
+  db = rocksdb_open(options, dbname, &err);
+  CheckNoError(err);
+  rocksdb_put(db, woptions, "foo", 3, "foovalue", 8, &err);
+  CheckNoError(err);
+  CheckGet(db, roptions, "foo", "foovalue");
+  rocksdb_put(db, woptions, "bar", 3, "barvalue", 8, &err);
+  CheckNoError(err);
+  CheckGet(db, roptions, "bar", "barvalue");
+  rocksdb_put(db, woptions, "baz", 3, "bazvalue", 8, &err);
+  CheckNoError(err);
+  CheckGet(db, roptions, "baz", "bazvalue");
+
+  // Force compaction
+  rocksdb_compact_range(db, NULL, 0, NULL, 0);
+  // should have filtered bar, but not foo
+  CheckGet(db, roptions, "foo", "foovalue");
+  CheckGet(db, roptions, "bar", NULL);
+  CheckGet(db, roptions, "baz", "newbazvalue");
+  return db;
+}
+
+// Custom compaction filter V2.
+static void CompactionFilterV2Destroy(void* arg) { }
+static const char* CompactionFilterV2Name(void* arg) {
+  return "TestCompactionFilterV2";
+}
+static void CompactionFilterV2Filter(
+    void* arg, int level, size_t num_keys,
+    const char* const* keys_list, const size_t* keys_list_sizes,
+    const char* const* existing_values_list, const size_t* existing_values_list_sizes,
+    char** new_values_list, size_t* new_values_list_sizes,
+    unsigned char* to_delete_list) {
+  size_t i;
+  for (i = 0; i < num_keys; i++) {
+    // If any value is "gc", it's removed.
+    if (existing_values_list_sizes[i] == 2 && memcmp(existing_values_list[i], "gc", 2) == 0) {
+      to_delete_list[i] = 1;
+    } else if (existing_values_list_sizes[i] == 6 && memcmp(existing_values_list[i], "gc all", 6) == 0) {
+      // If any value is "gc all", all keys are removed.
+      size_t j;
+      for (j = 0; j < num_keys; j++) {
+        to_delete_list[j] = 1;
+      }
+      return;
+    } else if (existing_values_list_sizes[i] == 6 && memcmp(existing_values_list[i], "change", 6) == 0) {
+      // If value is "change", set changed value to "changed".
+      size_t len;
+      len = strlen("changed");
+      new_values_list[i] = malloc(len);
+      memcpy(new_values_list[i], "changed", len);
+      new_values_list_sizes[i] = len;
+    } else {
+      // Otherwise, no keys are removed.
+    }
+  }
+}
+
+// Custom compaction filter factory V2.
+static void CompactionFilterFactoryV2Destroy(void* arg) {
+  rocksdb_slicetransform_destroy((rocksdb_slicetransform_t*)arg);
+}
+static const char* CompactionFilterFactoryV2Name(void* arg) {
+  return "TestCompactionFilterFactoryV2";
+}
+static rocksdb_compactionfilterv2_t* CompactionFilterFactoryV2Create(
+    void* state, const rocksdb_compactionfiltercontext_t* context) {
+  return rocksdb_compactionfilterv2_create(state, CompactionFilterV2Destroy,
+                                           CompactionFilterV2Filter,
+                                           CompactionFilterV2Name);
+}
+
 // Custom merge operator
 static void MergeOperatorDestroy(void* arg) { }
 static const char* MergeOperatorName(void* arg) {
@@ -277,6 +398,24 @@ int main(int argc, char** argv) {
    rocksdb_writebatch_destroy(wb);
  }

+  StartPhase("writebatch_rep");
+  {
+    rocksdb_writebatch_t* wb1 = rocksdb_writebatch_create();
+    rocksdb_writebatch_put(wb1, "baz", 3, "d", 1);
+    rocksdb_writebatch_put(wb1, "quux", 4, "e", 1);
+    rocksdb_writebatch_delete(wb1, "quux", 4);
+    size_t repsize1 = 0;
+    const char* rep = rocksdb_writebatch_data(wb1, &repsize1);
+    rocksdb_writebatch_t* wb2 = rocksdb_writebatch_create_from(rep, repsize1);
+    CheckCondition(rocksdb_writebatch_count(wb1) ==
+                   rocksdb_writebatch_count(wb2));
+    size_t repsize2 = 0;
+    CheckCondition(
+        memcmp(rep, rocksdb_writebatch_data(wb2, &repsize2), repsize1) == 0);
+    rocksdb_writebatch_destroy(wb1);
+    rocksdb_writebatch_destroy(wb2);
+  }
+
  StartPhase("iter");
  {
    rocksdb_iterator_t* iter = rocksdb_create_iterator(db, roptions);
@@ -407,6 +546,82 @@ int main(int argc, char** argv) {
    rocksdb_filterpolicy_destroy(policy);
  }

+  StartPhase("compaction_filter");
+  {
+    rocksdb_options_t* options = rocksdb_options_create();
+    rocksdb_options_set_create_if_missing(options, 1);
+    rocksdb_compactionfilter_t* cfilter;
+    cfilter = rocksdb_compactionfilter_create(NULL, CFilterDestroy,
+                                              CFilterFilter, CFilterName);
+    // Create new database
+    rocksdb_close(db);
+    rocksdb_destroy_db(options, dbname, &err);
+    rocksdb_options_set_compaction_filter(options, cfilter);
+    db = CheckCompaction(db, options, roptions, woptions);
+
+    rocksdb_options_set_compaction_filter(options, NULL);
+    rocksdb_compactionfilter_destroy(cfilter);
+    rocksdb_options_destroy(options);
+  }
+
+  StartPhase("compaction_filter_factory");
+  {
+    rocksdb_options_t* options = rocksdb_options_create();
+    rocksdb_options_set_create_if_missing(options, 1);
+    rocksdb_compactionfilterfactory_t* factory;
+    factory = rocksdb_compactionfilterfactory_create(
+        NULL, CFilterFactoryDestroy, CFilterCreate, CFilterFactoryName);
+    // Create new database
+    rocksdb_close(db);
+    rocksdb_destroy_db(options, dbname, &err);
+    rocksdb_options_set_compaction_filter_factory(options, factory);
+    db = CheckCompaction(db, options, roptions, woptions);
+
+    rocksdb_options_set_compaction_filter_factory(options, NULL);
+    rocksdb_options_destroy(options);
+  }
+
+  StartPhase("compaction_filter_v2");
+  {
+    rocksdb_compactionfilterfactoryv2_t* factory;
+    rocksdb_slicetransform_t* prefix_extractor;
+    prefix_extractor = rocksdb_slicetransform_create_fixed_prefix(3);
+    factory = rocksdb_compactionfilterfactoryv2_create(
+        prefix_extractor, prefix_extractor, CompactionFilterFactoryV2Destroy,
+        CompactionFilterFactoryV2Create, CompactionFilterFactoryV2Name);
+    // Create new database
+    rocksdb_close(db);
+    rocksdb_destroy_db(options, dbname, &err);
+    rocksdb_options_set_compaction_filter_factory_v2(options, factory);
+    db = rocksdb_open(options, dbname, &err);
+    CheckNoError(err);
+    // Only foo2 is GC'd, foo3 is changed.
+    rocksdb_put(db, woptions, "foo1", 4, "no gc", 5, &err);
+    CheckNoError(err);
+    rocksdb_put(db, woptions, "foo2", 4, "gc", 2, &err);
+    CheckNoError(err);
+    rocksdb_put(db, woptions, "foo3", 4, "change", 6, &err);
+    CheckNoError(err);
+    // All bars are GC'd.
+    rocksdb_put(db, woptions, "bar1", 4, "no gc", 5, &err);
+    CheckNoError(err);
+    rocksdb_put(db, woptions, "bar2", 4, "gc all", 6, &err);
+    CheckNoError(err);
+    rocksdb_put(db, woptions, "bar3", 4, "no gc", 5, &err);
+    CheckNoError(err);
+    // Compact the DB to garbage collect.
+    rocksdb_compact_range(db, NULL, 0, NULL, 0);
+
+    // Verify foo entries.
+    CheckGet(db, roptions, "foo1", "no gc");
+    CheckGet(db, roptions, "foo2", NULL);
+    CheckGet(db, roptions, "foo3", "changed");
+    // Verify bar entries were all deleted.
+    CheckGet(db, roptions, "bar1", NULL);
+    CheckGet(db, roptions, "bar2", NULL);
+    CheckGet(db, roptions, "bar3", NULL);
+  }
+
  StartPhase("merge_operator");
  {
    rocksdb_mergeoperator_t* merge_operator;
@@ -433,16 +648,93 @@ int main(int argc, char** argv) {

  }

+  StartPhase("columnfamilies");
+  {
+    rocksdb_close(db);
+    rocksdb_destroy_db(options, dbname, &err);
+    CheckNoError(err)
+
+    rocksdb_options_t* db_options = rocksdb_options_create();
+    rocksdb_options_set_create_if_missing(db_options, 1);
+    db = rocksdb_open(db_options, dbname, &err);
+    CheckNoError(err)
+    rocksdb_column_family_handle_t* cfh;
+    cfh = rocksdb_create_column_family(db, db_options, "cf1", &err);
+    rocksdb_column_family_handle_destroy(cfh);
+    CheckNoError(err);
+    rocksdb_close(db);
+
+    size_t cflen;
+    char** column_fams = rocksdb_list_column_families(db_options, dbname, &cflen, &err);
+    CheckNoError(err);
+    CheckEqual("default", column_fams[0], 7);
+    CheckEqual("cf1", column_fams[1], 3);
+    CheckCondition(cflen == 2);
+    rocksdb_list_column_families_destroy(column_fams, cflen);
+
+    rocksdb_options_t* cf_options = rocksdb_options_create();
+
+    const char* cf_names[2] = {"default", "cf1"};
+    const rocksdb_options_t* cf_opts[2] = {cf_options, cf_options};
+    rocksdb_column_family_handle_t* handles[2];
+    db = rocksdb_open_column_families(db_options, dbname, 2, cf_names, cf_opts, handles, &err);
+    CheckNoError(err);
+
+    rocksdb_put_cf(db, woptions, handles[1], "foo", 3, "hello", 5, &err);
+    CheckNoError(err);
+
+    CheckGetCF(db, roptions, handles[1], "foo", "hello");
+
+    rocksdb_delete_cf(db, woptions, handles[1], "foo", 3, &err);
+    CheckNoError(err);
+
+    CheckGetCF(db, roptions, handles[1], "foo", NULL);
+
+    rocksdb_writebatch_t* wb = rocksdb_writebatch_create();
+    rocksdb_writebatch_put_cf(wb, handles[1], "baz", 3, "a", 1);
+    rocksdb_writebatch_clear(wb);
+    rocksdb_writebatch_put_cf(wb, handles[1], "bar", 3, "b", 1);
+    rocksdb_writebatch_put_cf(wb, handles[1], "box", 3, "c", 1);
+    rocksdb_writebatch_delete_cf(wb, handles[1], "bar", 3);
+    rocksdb_write(db, woptions, wb, &err);
+    CheckNoError(err);
+    CheckGetCF(db, roptions, handles[1], "baz", NULL);
+    CheckGetCF(db, roptions, handles[1], "bar", NULL);
+    CheckGetCF(db, roptions, handles[1], "box", "c");
+    rocksdb_writebatch_destroy(wb);
+
+    rocksdb_iterator_t* iter = rocksdb_create_iterator_cf(db, roptions, handles[1]);
+    CheckCondition(!rocksdb_iter_valid(iter));
+    rocksdb_iter_seek_to_first(iter);
+    CheckCondition(rocksdb_iter_valid(iter));
+
+    int i;
+    for (i = 0; rocksdb_iter_valid(iter) != 0; rocksdb_iter_next(iter)) {
+      i++;
+    }
+    CheckCondition(i == 1);
+    rocksdb_iter_get_error(iter, &err);
+    CheckNoError(err);
+    rocksdb_iter_destroy(iter);
+
+    rocksdb_drop_column_family(db, handles[1], &err);
+    CheckNoError(err);
+    for (i = 0; i < 2; i++) {
+      rocksdb_column_family_handle_destroy(handles[i]);
+    }
+    rocksdb_close(db);
+    rocksdb_destroy_db(options, dbname, &err);
+    rocksdb_options_destroy(db_options);
+    rocksdb_options_destroy(cf_options);
+  }
+
  StartPhase("prefix");
  {
    // Create new database
-    rocksdb_close(db);
-    rocksdb_destroy_db(options, dbname, &err);
-
    rocksdb_filterpolicy_t* policy = rocksdb_filterpolicy_create_bloom(10);
    rocksdb_options_set_filter_policy(options, policy);
    rocksdb_options_set_prefix_extractor(options, rocksdb_slicetransform_create_fixed_prefix(3));
-    rocksdb_options_set_hash_skip_list_rep(options, 50000, 4, 4);
+    rocksdb_options_set_hash_skip_list_rep(options, 5000, 4, 4);
    rocksdb_options_set_plain_table_factory(options, 4, 10, 0.75, 16);

    db = rocksdb_open(options, dbname, &err);
@@ -480,6 +772,7 @@ int main(int argc, char** argv) {
    rocksdb_filterpolicy_destroy(policy);
  }

+
  StartPhase("cleanup");
  rocksdb_close(db);
  rocksdb_options_destroy(options);
@@ -12,6 +12,7 @@
 #include <vector>
 #include <string>
 #include <algorithm>
+#include <limits>

 #include "db/db_impl.h"
 #include "db/version_set.h"
@@ -48,15 +49,6 @@ ColumnFamilyHandleImpl::~ColumnFamilyHandleImpl() {

 uint32_t ColumnFamilyHandleImpl::GetID() const { return cfd()->GetID(); }

-namespace {
-// Fix user-supplied options to be reasonable
-template <class T, class V>
-static void ClipToRange(T* ptr, V minvalue, V maxvalue) {
-  if (static_cast<V>(*ptr) > maxvalue) *ptr = maxvalue;
-  if (static_cast<V>(*ptr) < minvalue) *ptr = minvalue;
-}
-}  // anonymous namespace
-
 ColumnFamilyOptions SanitizeOptions(const InternalKeyComparator* icmp,
                                    const InternalFilterPolicy* ipolicy,
                                    const ColumnFamilyOptions& src) {
@@ -91,6 +83,9 @@ ColumnFamilyOptions SanitizeOptions(const InternalKeyComparator* icmp,
  if (result.soft_rate_limit > result.hard_rate_limit) {
    result.soft_rate_limit = result.hard_rate_limit;
  }
+  if (result.max_write_buffer_number < 2) {
+    result.max_write_buffer_number = 2;
+  }
  if (!result.prefix_extractor) {
    assert(result.memtable_factory);
    Slice name = result.memtable_factory->Name();
@@ -104,14 +99,26 @@ ColumnFamilyOptions SanitizeOptions(const InternalKeyComparator* icmp,
  // All user defined properties collectors will be wrapped by
  // UserKeyTablePropertiesCollector since for them they only have the
  // knowledge of the user keys; internal keys are invisible to them.
-  auto& collectors = result.table_properties_collectors;
-  for (size_t i = 0; i < result.table_properties_collectors.size(); ++i) {
-    assert(collectors[i]);
-    collectors[i] =
-        std::make_shared<UserKeyTablePropertiesCollector>(collectors[i]);
+  auto& collector_factories = result.table_properties_collector_factories;
+  for (size_t i = 0; i < result.table_properties_collector_factories.size();
+       ++i) {
+    assert(collector_factories[i]);
+    collector_factories[i] =
+        std::make_shared<UserKeyTablePropertiesCollectorFactory>(
+            collector_factories[i]);
  }
  // Add collector to collect internal key statistics
-  collectors.push_back(std::make_shared<InternalKeyPropertiesCollector>());
+  collector_factories.push_back(
+      std::make_shared<InternalKeyPropertiesCollectorFactory>());
+
+  if (result.compaction_style == kCompactionStyleFIFO) {
+    result.num_levels = 1;
+    // since we delete level0 files in FIFO compaction when there are too many
+    // of them, these options don't really mean anything
+    result.level0_file_num_compaction_trigger = std::numeric_limits<int>::max();
+    result.level0_slowdown_writes_trigger = std::numeric_limits<int>::max();
+    result.level0_stop_writes_trigger = std::numeric_limits<int>::max();
+  }

  return result;
 }
@@ -175,8 +182,7 @@ void SuperVersionUnrefHandle(void* ptr) {
 }
 }  // anonymous namespace

-ColumnFamilyData::ColumnFamilyData(const std::string& dbname, uint32_t id,
-                                   const std::string& name,
+ColumnFamilyData::ColumnFamilyData(uint32_t id, const std::string& name,
                                   Version* dummy_versions, Cache* table_cache,
                                   const ColumnFamilyOptions& options,
                                   const DBOptions* db_options,
@@ -193,7 +199,7 @@ ColumnFamilyData::ColumnFamilyData(const std::string& dbname, uint32_t id,
      options_(*db_options, SanitizeOptions(&internal_comparator_,
                                            &internal_filter_policy_, options)),
      mem_(nullptr),
-      imm_(options.min_write_buffer_number_to_merge),
+      imm_(options_.min_write_buffer_number_to_merge),
      super_version_(nullptr),
      super_version_number_(0),
      local_sv_(new ThreadLocalPtr(&SuperVersionUnrefHandle)),
@@ -206,16 +212,19 @@ ColumnFamilyData::ColumnFamilyData(const std::string& dbname, uint32_t id,

  // if dummy_versions is nullptr, then this is a dummy column family.
  if (dummy_versions != nullptr) {
-    internal_stats_.reset(new InternalStats(options.num_levels, db_options->env,
-                                            db_options->statistics.get()));
-    table_cache_.reset(
-        new TableCache(dbname, &options_, storage_options, table_cache));
+    internal_stats_.reset(
+        new InternalStats(options_.num_levels, db_options->env, this));
+    table_cache_.reset(new TableCache(&options_, storage_options, table_cache));
    if (options_.compaction_style == kCompactionStyleUniversal) {
      compaction_picker_.reset(
          new UniversalCompactionPicker(&options_, &internal_comparator_));
-    } else {
+    } else if (options_.compaction_style == kCompactionStyleLevel) {
      compaction_picker_.reset(
          new LevelCompactionPicker(&options_, &internal_comparator_));
+    } else {
+      assert(options_.compaction_style == kCompactionStyleFIFO);
+      compaction_picker_.reset(
+          new FIFOCompactionPicker(&options_, &internal_comparator_));
    }

    Log(options_.info_log, "Options for column family \"%s\":\n",
@@ -223,6 +232,8 @@ ColumnFamilyData::ColumnFamilyData(const std::string& dbname, uint32_t id,
    const ColumnFamilyOptions* cf_options = &options_;
    cf_options->Dump(options_.info_log.get());
  }
+
+  RecalculateWriteStallConditions();
 }

 // DB mutex held
@@ -275,6 +286,35 @@ ColumnFamilyData::~ColumnFamilyData() {
  }
 }

+void ColumnFamilyData::RecalculateWriteStallConditions() {
+  need_wait_for_num_memtables_ =
+    (imm()->size() == options()->max_write_buffer_number - 1);
+
+  if (current_ != nullptr) {
+    need_wait_for_num_level0_files_ =
+      (current_->NumLevelFiles(0) >= options()->level0_stop_writes_trigger);
+  } else {
+    need_wait_for_num_level0_files_ = false;
+  }
+
+  RecalculateWriteStallRateLimitsConditions();
+}
+
+void ColumnFamilyData::RecalculateWriteStallRateLimitsConditions() {
+  if (current_ != nullptr) {
+    exceeds_hard_rate_limit_ =
+        (options()->hard_rate_limit > 1.0 &&
+         current_->MaxCompactionScore() > options()->hard_rate_limit);
+
+    exceeds_soft_rate_limit_ =
+        (options()->soft_rate_limit > 0.0 &&
+         current_->MaxCompactionScore() > options()->soft_rate_limit);
+  } else {
+    exceeds_hard_rate_limit_ = false;
+    exceeds_soft_rate_limit_ = false;
+  }
+}
+
 const EnvOptions* ColumnFamilyData::soptions() const {
  return &(column_family_set_->storage_options_);
 }
@@ -296,15 +336,19 @@ void ColumnFamilyData::CreateNewMemtable() {
 }

 Compaction* ColumnFamilyData::PickCompaction(LogBuffer* log_buffer) {
-  return compaction_picker_->PickCompaction(current_, log_buffer);
+  auto result = compaction_picker_->PickCompaction(current_, log_buffer);
+  RecalculateWriteStallRateLimitsConditions();
+  return result;
 }

 Compaction* ColumnFamilyData::CompactRange(int input_level, int output_level,
+                                           uint32_t output_path_id,
                                           const InternalKey* begin,
                                           const InternalKey* end,
                                           InternalKey** compaction_end) {
  return compaction_picker_->CompactRange(current_, input_level, output_level,
-                                          begin, end, compaction_end);
+                                          output_path_id, begin, end,
+                                          compaction_end);
 }

 SuperVersion* ColumnFamilyData::GetReferencedSuperVersion(
@@ -400,6 +444,9 @@ SuperVersion* ColumnFamilyData::InstallSuperVersion(
  if (column_family_set_->db_options_->allow_thread_local) {
    ResetThreadLocalSuperVersions();
  }
+
+  RecalculateWriteStallConditions();
+
  if (old_superversion != nullptr && old_superversion->Unref()) {
    old_superversion->Cleanup();
    return old_superversion;  // will let caller delete outside of mutex
@@ -428,7 +475,7 @@ ColumnFamilySet::ColumnFamilySet(const std::string& dbname,
                                 const EnvOptions& storage_options,
                                 Cache* table_cache)
    : max_column_family_(0),
-      dummy_cfd_(new ColumnFamilyData(dbname, 0, "", nullptr, nullptr,
+      dummy_cfd_(new ColumnFamilyData(0, "", nullptr, nullptr,
                                      ColumnFamilyOptions(), db_options,
                                      storage_options_, nullptr)),
      default_cfd_cache_(nullptr),
@@ -489,14 +536,18 @@ void ColumnFamilySet::UpdateMaxColumnFamily(uint32_t new_max_column_family) {
  max_column_family_ = std::max(new_max_column_family, max_column_family_);
 }

+size_t ColumnFamilySet::NumberOfColumnFamilies() const {
+  return column_families_.size();
+}
+
 // under a DB mutex
 ColumnFamilyData* ColumnFamilySet::CreateColumnFamily(
    const std::string& name, uint32_t id, Version* dummy_versions,
    const ColumnFamilyOptions& options) {
  assert(column_families_.find(name) == column_families_.end());
  ColumnFamilyData* new_cfd =
-      new ColumnFamilyData(db_name_, id, name, dummy_versions, table_cache_,
-                           options, db_options_, storage_options_, this);
+      new ColumnFamilyData(id, name, dummy_versions, table_cache_, options,
+                           db_options_, storage_options_, this);
  Lock();
  column_families_.insert({name, id});
  column_family_data_.insert({id, new_cfd});
@@ -180,12 +180,13 @@ class ColumnFamilyData {
  void SetCurrent(Version* current);
  void CreateNewMemtable();

-  TableCache* table_cache() { return table_cache_.get(); }
+  TableCache* table_cache() const { return table_cache_.get(); }

  // See documentation in compaction_picker.h
  Compaction* PickCompaction(LogBuffer* log_buffer);
  Compaction* CompactRange(int input_level, int output_level,
-                           const InternalKey* begin, const InternalKey* end,
+                           uint32_t output_path_id, const InternalKey* begin,
+                           const InternalKey* end,
                           InternalKey** compaction_end);

  CompactionPicker* compaction_picker() { return compaction_picker_.get(); }
@@ -229,15 +230,39 @@ class ColumnFamilyData {
    return need_slowdown_for_num_level0_files_;
  }

+  bool NeedWaitForNumLevel0Files() const {
+    return need_wait_for_num_level0_files_;
+  }
+
+  bool NeedWaitForNumMemtables() const {
+    return need_wait_for_num_memtables_;
+  }
+
+  bool ExceedsSoftRateLimit() const {
+    return exceeds_soft_rate_limit_;
+  }
+
+  bool ExceedsHardRateLimit() const {
+    return exceeds_hard_rate_limit_;
+  }
+
 private:
  friend class ColumnFamilySet;
-  ColumnFamilyData(const std::string& dbname, uint32_t id,
-                   const std::string& name, Version* dummy_versions,
-                   Cache* table_cache, const ColumnFamilyOptions& options,
+  ColumnFamilyData(uint32_t id, const std::string& name,
+                   Version* dummy_versions, Cache* table_cache,
+                   const ColumnFamilyOptions& options,
                   const DBOptions* db_options,
                   const EnvOptions& storage_options,
                   ColumnFamilySet* column_family_set);

+  // Recalculate some small conditions, which are changed only during
+  // compaction, adding new memtable and/or
+  // recalculation of compaction score. These values are used in
+  // DBImpl::MakeRoomForWrite function to decide, if it need to make
+  // a write stall
+  void RecalculateWriteStallConditions();
+  void RecalculateWriteStallRateLimitsConditions();
+
  uint32_t id_;
  const std::string name_;
  Version* dummy_versions_;  // Head of circular doubly-linked list of versions.
@@ -282,6 +307,22 @@ class ColumnFamilyData {
  // we have too many level 0 files
  bool need_slowdown_for_num_level0_files_;

+  // These 4 variables are updated only after compaction,
+  // adding new memtable, flushing memtables to files
+  // and/or add recalculation of compaction score.
+  // That's why theirs values are cached in ColumnFamilyData.
+  // Recalculation is made by RecalculateWriteStallConditions and
+  // RecalculateWriteStallRateLimitsConditions function. They are used
+  // in DBImpl::MakeRoomForWrite function to decide, if it need
+  // to sleep during write operation
+  bool need_wait_for_num_memtables_;
+
+  bool need_wait_for_num_level0_files_;
+
+  bool exceeds_hard_rate_limit_;
+
+  bool exceeds_soft_rate_limit_;
+
  // An object that keeps all the compaction stats
  // and picks the next compaction
  std::unique_ptr<CompactionPicker> compaction_picker_;
@@ -302,8 +343,8 @@ class ColumnFamilyData {
 // family might get dropped when the DB mutex is released
 // * GetDefault() -- thread safe
 // * GetColumnFamily() -- either inside of DB mutex or call Lock() <-> Unlock()
-// * GetNextColumnFamilyID(), GetMaxColumnFamily(), UpdateMaxColumnFamily() --
-// inside of DB mutex
+// * GetNextColumnFamilyID(), GetMaxColumnFamily(), UpdateMaxColumnFamily(),
+// NumberOfColumnFamilies -- inside of DB mutex
 class ColumnFamilySet {
 public:
  // ColumnFamilySet supports iteration
@@ -342,6 +383,7 @@ class ColumnFamilySet {
  uint32_t GetNextColumnFamilyID();
  uint32_t GetMaxColumnFamily();
  void UpdateMaxColumnFamily(uint32_t new_max_column_family);
+  size_t NumberOfColumnFamilies() const;

  ColumnFamilyData* CreateColumnFamily(const std::string& name, uint32_t id,
                                       Version* dummy_version,
@@ -749,7 +749,6 @@ TEST(ColumnFamilyTest, DifferentCompactionStyles) {
  default_cf.filter_policy = nullptr;
  default_cf.no_block_cache = true;
  default_cf.source_compaction_factor = 100;
-  default_cf.disable_seek_compaction = false;

  one.compaction_style = kCompactionStyleUniversal;
  // trigger compaction if there are >= 4 files
@@ -764,33 +763,6 @@ TEST(ColumnFamilyTest, DifferentCompactionStyles) {

  Reopen({default_cf, one, two});

-  // SETUP column family "default" - test read compaction
-  ASSERT_EQ("", FilesPerLevel(0));
-  PutRandomData(0, 1, 4096);
-  ASSERT_OK(Flush(0));
-  ASSERT_EQ("0,0,1", FilesPerLevel(0));
-  // write 8MB
-  PutRandomData(0, 2000, 4096);
-  ASSERT_OK(Flush(0));
-  // clear levels 0 and 1
-  dbfull()->TEST_CompactRange(0, nullptr, nullptr, handles_[0]);
-  dbfull()->TEST_CompactRange(1, nullptr, nullptr, handles_[0]);
-  ASSERT_EQ(NumTableFilesAtLevel(0, 0), 0);
-  ASSERT_EQ(NumTableFilesAtLevel(1, 0), 0);
-  // write some new keys into level 0 and 1
-  PutRandomData(0, 1024, 512);
-  ASSERT_OK(Flush(0));
-  WaitForCompaction();
-  PutRandomData(0, 10, 512);
-  ASSERT_OK(Flush(0));
-  // remember number of files in each level
-  int l1 = NumTableFilesAtLevel(0, 0);
-  int l2 = NumTableFilesAtLevel(1, 0);
-  int l3 = NumTableFilesAtLevel(2, 0);
-  ASSERT_NE(l1, 0);
-  ASSERT_NE(l2, 0);
-  ASSERT_NE(l3, 0);
-
  // SETUP column family "one" -- universal style
  for (int i = 0; i < one.level0_file_num_compaction_trigger - 1; ++i) {
    PutRandomData(1, 11, 10000);
@@ -805,12 +777,6 @@ TEST(ColumnFamilyTest, DifferentCompactionStyles) {
    ASSERT_EQ(std::to_string(i + 1), FilesPerLevel(2));
  }

-  // TRIGGER compaction "default"
-  // read a bunch of times, trigger read compaction
-  for (int i = 0; i < 200000; ++i) {
-    Get(0, std::to_string(i));
-  }
-
  // TRIGGER compaction "one"
  PutRandomData(1, 12, 10000);

@@ -820,13 +786,6 @@ TEST(ColumnFamilyTest, DifferentCompactionStyles) {
  // WAIT for compactions
  WaitForCompaction();

-  // VERIFY compaction "default"
-  // verify that the number of files have decreased
-  // in some level, indicating that there was a compaction
-  ASSERT_TRUE(NumTableFilesAtLevel(0, 0) < l1 ||
-              NumTableFilesAtLevel(1, 0) < l2 ||
-              NumTableFilesAtLevel(2, 0) < l3);
-
  // VERIFY compaction "one"
  ASSERT_EQ("1", FilesPerLevel(1));

@@ -898,6 +857,7 @@ TEST(ColumnFamilyTest, NewIteratorsTest) {
 TEST(ColumnFamilyTest, ReadOnlyDBTest) {
  Open();
  CreateColumnFamiliesAndReopen({"one", "two", "three", "four"});
+  ASSERT_OK(Put(0, "a", "b"));
  ASSERT_OK(Put(1, "foo", "bla"));
  ASSERT_OK(Put(2, "foo", "blabla"));
  ASSERT_OK(Put(3, "foo", "blablabla"));
@@ -911,6 +871,29 @@ TEST(ColumnFamilyTest, ReadOnlyDBTest) {
  ASSERT_EQ("bla", Get(1, "foo"));
  ASSERT_EQ("blablablabla", Get(2, "foo"));

+
+  // test newiterators
+  {
+    std::vector<Iterator*> iterators;
+    ASSERT_OK(db_->NewIterators(ReadOptions(), handles_, &iterators));
+    for (auto it : iterators) {
+      it->SeekToFirst();
+    }
+    ASSERT_EQ(IterStatus(iterators[0]), "a->b");
+    ASSERT_EQ(IterStatus(iterators[1]), "foo->bla");
+    ASSERT_EQ(IterStatus(iterators[2]), "foo->blablablabla");
+    for (auto it : iterators) {
+      it->Next();
+    }
+    ASSERT_EQ(IterStatus(iterators[0]), "(invalid)");
+    ASSERT_EQ(IterStatus(iterators[1]), "(invalid)");
+    ASSERT_EQ(IterStatus(iterators[2]), "(invalid)");
+
+    for (auto it : iterators) {
+      delete it;
+    }
+  }
+
  Close();
  // can't open dropped column family
  Status s = OpenReadOnly({"default", "one", "two"});
@@ -970,6 +953,15 @@ TEST(ColumnFamilyTest, FlushStaleColumnFamilies) {
  Close();
 }

+TEST(ColumnFamilyTest, CreateMissingColumnFamilies) {
+  Status s = TryOpen({"one", "two"});
+  ASSERT_TRUE(!s.ok());
+  db_options_.create_missing_column_families = true;
+  s = TryOpen({"default", "one", "two"});
+  ASSERT_TRUE(s.ok());
+  Close();
+}
+
 }  // namespace rocksdb

 int main(int argc, char** argv) {
@@ -8,31 +8,41 @@
 // found in the LICENSE file. See the AUTHORS file for names of contributors.

 #include "db/compaction.h"
+
+#define __STDC_FORMAT_MACROS
+#include <inttypes.h>
+#include <vector>
+
 #include "db/column_family.h"
+#include "util/logging.h"

 namespace rocksdb {

-static uint64_t TotalFileSize(const std::vector<FileMetaData*>& files) {
+uint64_t TotalFileSize(const std::vector<FileMetaData*>& files) {
  uint64_t sum = 0;
  for (size_t i = 0; i < files.size() && files[i]; i++) {
-    sum += files[i]->file_size;
+    sum += files[i]->fd.GetFileSize();
  }
  return sum;
 }

-Compaction::Compaction(Version* input_version, int level, int out_level,
+Compaction::Compaction(Version* input_version, int start_level, int out_level,
                       uint64_t target_file_size,
                       uint64_t max_grandparent_overlap_bytes,
-                       bool seek_compaction, bool enable_compression)
-    : level_(level),
-      out_level_(out_level),
+                       uint32_t output_path_id,
+                       CompressionType output_compression, bool seek_compaction,
+                       bool deletion_compaction)
+    : start_level_(start_level),
+      output_level_(out_level),
      max_output_file_size_(target_file_size),
      max_grandparent_overlap_bytes_(max_grandparent_overlap_bytes),
      input_version_(input_version),
      number_levels_(input_version_->NumberLevels()),
      cfd_(input_version_->cfd_),
+      output_path_id_(output_path_id),
+      output_compression_(output_compression),
      seek_compaction_(seek_compaction),
-      enable_compression_(enable_compression),
+      deletion_compaction_(deletion_compaction),
      grandparent_index_(0),
      seen_key_(false),
      overlapped_bytes_(0),
@@ -51,6 +61,12 @@ Compaction::Compaction(Version* input_version, int level, int out_level,
  for (int i = 0; i < number_levels_; i++) {
    level_ptrs_[i] = 0;
  }
+  int num_levels = output_level_ - start_level_ + 1;
+  input_levels_.resize(num_levels);
+  inputs_.resize(num_levels);
+  for (int i = 0; i < num_levels; ++i) {
+    inputs_[i].level = start_level_ + i;
+  }
 }

 Compaction::~Compaction() {
@@ -65,40 +81,50 @@ Compaction::~Compaction() {
  }
 }

+void Compaction::GenerateFileLevels() {
+  input_levels_.resize(num_input_levels());
+  for (int which = 0; which < num_input_levels(); which++) {
+    DoGenerateFileLevel(&input_levels_[which], inputs_[which].files, &arena_);
+  }
+}
+
 bool Compaction::IsTrivialMove() const {
  // Avoid a move if there is lots of overlapping grandparent data.
  // Otherwise, the move could create a parent file that will require
  // a very expensive merge later on.
-  // If level_== out_level_, the purpose is to force compaction filter to be
-  // applied to that level, and thus cannot be a trivia move.
-  return (level_ != out_level_ &&
+  // If start_level_== output_level_, the purpose is to force compaction
+  // filter to be applied to that level, and thus cannot be a trivia move.
+  return (start_level_ != output_level_ &&
+          num_input_levels() == 2 &&
          num_input_files(0) == 1 &&
          num_input_files(1) == 0 &&
          TotalFileSize(grandparents_) <= max_grandparent_overlap_bytes_);
 }

 void Compaction::AddInputDeletions(VersionEdit* edit) {
-  for (int which = 0; which < 2; which++) {
+  for (int which = 0; which < num_input_levels(); which++) {
    for (size_t i = 0; i < inputs_[which].size(); i++) {
-      edit->DeleteFile(level_ + which, inputs_[which][i]->number);
+      edit->DeleteFile(level(which), inputs_[which][i]->fd.GetNumber());
    }
  }
 }

-bool Compaction::IsBaseLevelForKey(const Slice& user_key) {
+bool Compaction::KeyNotExistsBeyondOutputLevel(const Slice& user_key) {
+  assert(cfd_->options()->compaction_style != kCompactionStyleFIFO);
  if (cfd_->options()->compaction_style == kCompactionStyleUniversal) {
    return bottommost_level_;
  }
  // Maybe use binary search to find right entry instead of linear search?
  const Comparator* user_cmp = cfd_->user_comparator();
-  for (int lvl = level_ + 2; lvl < number_levels_; lvl++) {
+  for (int lvl = output_level_ + 1; lvl < number_levels_; lvl++) {
    const std::vector<FileMetaData*>& files = input_version_->files_[lvl];
    for (; level_ptrs_[lvl] < files.size(); ) {
      FileMetaData* f = files[level_ptrs_[lvl]];
      if (user_cmp->Compare(user_key, f->largest.user_key()) <= 0) {
        // We've advanced far enough
        if (user_cmp->Compare(user_key, f->smallest.user_key()) >= 0) {
-          // Key falls in this file's range, so definitely not base level
+          // Key falls in this file's range, so definitely
+          // exists beyond output level
          return false;
        }
        break;
@@ -116,7 +142,7 @@ bool Compaction::ShouldStopBefore(const Slice& internal_key) {
      icmp->Compare(internal_key,
                    grandparents_[grandparent_index_]->largest.Encode()) > 0) {
    if (seen_key_) {
-      overlapped_bytes_ += grandparents_[grandparent_index_]->file_size;
+      overlapped_bytes_ += grandparents_[grandparent_index_]->fd.GetFileSize();
    }
    assert(grandparent_index_ + 1 >= grandparents_.size() ||
           icmp->Compare(grandparents_[grandparent_index_]->largest.Encode(),
@@ -136,19 +162,19 @@ bool Compaction::ShouldStopBefore(const Slice& internal_key) {
 }

 // Mark (or clear) each file that is being compacted
-void Compaction::MarkFilesBeingCompacted(bool value) {
-  for (int i = 0; i < 2; i++) {
-    std::vector<FileMetaData*> v = inputs_[i];
+void Compaction::MarkFilesBeingCompacted(bool mark_as_compacted) {
+  for (int i = 0; i < num_input_levels(); i++) {
    for (unsigned int j = 0; j < inputs_[i].size(); j++) {
-      assert(value ? !inputs_[i][j]->being_compacted :
-                      inputs_[i][j]->being_compacted);
-      inputs_[i][j]->being_compacted = value;
+      assert(mark_as_compacted ? !inputs_[i][j]->being_compacted :
+                                  inputs_[i][j]->being_compacted);
+      inputs_[i][j]->being_compacted = mark_as_compacted;
    }
  }
 }

 // Is this compaction producing files at the bottommost level?
-void Compaction::SetupBottomMostLevel(bool isManual) {
+void Compaction::SetupBottomMostLevel(bool is_manual) {
+  assert(cfd_->options()->compaction_style != kCompactionStyleFIFO);
  if (cfd_->options()->compaction_style == kCompactionStyleUniversal) {
    // If universal compaction style is used and manual
    // compaction is occuring, then we are guaranteed that
@@ -156,13 +182,14 @@ void Compaction::SetupBottomMostLevel(bool isManual) {
    // run. We can safely set bottommost_level_ = true.
    // If it is not manual compaction, then bottommost_level_
    // is already set when the Compaction was created.
-    if (isManual) {
+    if (is_manual) {
      bottommost_level_ = true;
    }
    return;
  }
  bottommost_level_ = true;
-  for (int i = output_level() + 1; i < number_levels_; i++) {
+  // checks whether there are files living beyond the output_level.
+  for (int i = output_level_ + 1; i < number_levels_; i++) {
    if (input_version_->NumLevelFiles(i) > 0) {
      bottommost_level_ = false;
      break;
@@ -188,74 +215,71 @@ void Compaction::ReleaseCompactionFiles(Status status) {
 }

 void Compaction::ResetNextCompactionIndex() {
-  input_version_->ResetNextCompactionIndex(level_);
+  input_version_->ResetNextCompactionIndex(start_level_);
 }

-/*
-for sizes >=10TB, print "XXTB"
-for sizes >=10GB, print "XXGB"
-etc.
-*/
-static void FileSizeSummary(unsigned long long sz, char* output, int len) {
-  const unsigned long long ull10 = 10;
-  if (sz >= ull10<<40) {
-    snprintf(output, len, "%lluTB", sz>>40);
-  } else if (sz >= ull10<<30) {
-    snprintf(output, len, "%lluGB", sz>>30);
-  } else if (sz >= ull10<<20) {
-    snprintf(output, len, "%lluMB", sz>>20);
-  } else if (sz >= ull10<<10) {
-    snprintf(output, len, "%lluKB", sz>>10);
-  } else {
-    snprintf(output, len, "%lluB", sz);
-  }
-}
-
-static int InputSummary(std::vector<FileMetaData*>& files, char* output,
-                         int len) {
+namespace {
+int InputSummary(const std::vector<FileMetaData*>& files, char* output,
+                 int len) {
  *output = '\0';
  int write = 0;
  for (unsigned int i = 0; i < files.size(); i++) {
    int sz = len - write;
    int ret;
    char sztxt[16];
-    FileSizeSummary((unsigned long long)files.at(i)->file_size, sztxt, 16);
-    ret = snprintf(output + write, sz, "%lu(%s) ",
-                   (unsigned long)files.at(i)->number,
-                   sztxt);
-    if (ret < 0 || ret >= sz)
-      break;
+    AppendHumanBytes(files.at(i)->fd.GetFileSize(), sztxt, 16);
+    ret = snprintf(output + write, sz, "%" PRIu64 "(%s) ",
+                   files.at(i)->fd.GetNumber(), sztxt);
+    if (ret < 0 || ret >= sz) break;
    write += ret;
  }
-  return write;
+  // if files.size() is non-zero, overwrite the last space
+  return write - !!files.size();
 }
+}  // namespace

 void Compaction::Summary(char* output, int len) {
-  int write = snprintf(output, len,
-      "Base version %lu Base level %d, seek compaction:%d, inputs: [",
-      (unsigned long)input_version_->GetVersionNumber(),
-      level_,
-      seek_compaction_);
+  int write =
+      snprintf(output, len, "Base version %" PRIu64
+                            " Base level %d, seek compaction:%d, inputs: [",
+               input_version_->GetVersionNumber(),
+               start_level_, seek_compaction_);
  if (write < 0 || write >= len) {
    return;
  }

-  write += InputSummary(inputs_[0], output+write, len-write);
-  if (write < 0 || write >= len) {
-    return;
+  for (int level = 0; level < num_input_levels(); ++level) {
+    if (level > 0) {
+      write += snprintf(output + write, len - write, "], [");
+      if (write < 0 || write >= len) {
+        return;
+      }
+    }
+    write += InputSummary(inputs_[level].files, output + write, len - write);
+    if (write < 0 || write >= len) {
+      return;
+    }
  }

-  write += snprintf(output+write, len-write, "],[");
-  if (write < 0 || write >= len) {
-    return;
-  }
+  snprintf(output + write, len - write, "]");
+}

-  write += InputSummary(inputs_[1], output+write, len-write);
-  if (write < 0 || write >= len) {
-    return;
-  }
+uint64_t Compaction::OutputFilePreallocationSize() {
+  uint64_t preallocation_size = 0;

-  snprintf(output+write, len-write, "]");
+  if (cfd_->options()->compaction_style == kCompactionStyleLevel) {
+    preallocation_size =
+        cfd_->compaction_picker()->MaxFileSizeForLevel(output_level());
+  } else {
+    for (int level = 0; level < num_input_levels(); ++level) {
+      for (const auto& f : inputs_[level].files) {
+        preallocation_size += f->fd.GetFileSize();
+      }
+    }
+  }
+  // Over-estimate slightly so we don't end up just barely crossing
+  // the threshold
+  return preallocation_size * 1.1;
 }

 }  // namespace rocksdb
@@ -8,59 +8,119 @@
 // found in the LICENSE file. See the AUTHORS file for names of contributors.

 #pragma once
+#include "util/arena.h"
+#include "util/autovector.h"
 #include "db/version_set.h"

 namespace rocksdb {

+// The structure that manages compaction input files associated
+// with the same physical level.
+struct CompactionInputFiles {
+  int level;
+  std::vector<FileMetaData*> files;
+  inline bool empty() const { return files.empty(); }
+  inline size_t size() const { return files.size(); }
+  inline void clear() { files.clear(); }
+  inline FileMetaData* operator[](int i) const { return files[i]; }
+};
+
 class Version;
 class ColumnFamilyData;

 // A Compaction encapsulates information about a compaction.
 class Compaction {
 public:
+  // No copying allowed
+  Compaction(const Compaction&) = delete;
+  void operator=(const Compaction&) = delete;
+
  ~Compaction();

-  // Return the level that is being compacted.  Inputs from "level"
-  // will be merged.
-  int level() const { return level_; }
+  // Returns the level associated to the specified compaction input level.
+  // If compaction_input_level is not specified, then input_level is set to 0.
+  int level(int compaction_input_level = 0) const {
+    return inputs_[compaction_input_level].level;
+  }

  // Outputs will go to this level
-  int output_level() const { return out_level_; }
+  int output_level() const { return output_level_; }
+
+  // Returns the number of input levels in this compaction.
+  int num_input_levels() const { return inputs_.size(); }

  // Return the object that holds the edits to the descriptor done
  // by this compaction.
-  VersionEdit* edit() { return edit_; }
+  VersionEdit* edit() const { return edit_; }

-  // "which" must be either 0 or 1
-  int num_input_files(int which) const { return inputs_[which].size(); }
+  // Returns the number of input files associated to the specified
+  // compaction input level.
+  // The function will return 0 if when "compaction_input_level" < 0
+  // or "compaction_input_level" >= "num_input_levels()".
+  int num_input_files(size_t compaction_input_level) const {
+    if (compaction_input_level < inputs_.size()) {
+      return inputs_[compaction_input_level].size();
+    }
+    return 0;
+  }

  // Returns input version of the compaction
  Version* input_version() const { return input_version_; }

+  // Returns the ColumnFamilyData associated with the compaction.
  ColumnFamilyData* column_family_data() const { return cfd_; }

-  // Return the ith input file at "level()+which" ("which" must be 0 or 1).
-  FileMetaData* input(int which, int i) const { return inputs_[which][i]; }
+  // Returns the file meta data of the 'i'th input file at the
+  // specified compaction input level.
+  // REQUIREMENT: "compaction_input_level" must be >= 0 and
+  //              < "input_levels()"
+  FileMetaData* input(size_t compaction_input_level, int i) const {
+    assert(compaction_input_level < inputs_.size());
+    return inputs_[compaction_input_level][i];
+  }

-  std::vector<FileMetaData*>* inputs(int which) { return &inputs_[which]; }
+  // Returns the list of file meta data of the specified compaction
+  // input level.
+  // REQUIREMENT: "compaction_input_level" must be >= 0 and
+  //              < "input_levels()"
+  std::vector<FileMetaData*>* const inputs(size_t compaction_input_level) {
+    assert(compaction_input_level < inputs_.size());
+    return &inputs_[compaction_input_level].files;
+  }
+
+  // Returns the FileLevel of the specified compaction input level.
+  FileLevel* input_levels(int compaction_input_level) {
+    return &input_levels_[compaction_input_level];
+  }

  // Maximum size of files to build during this compaction.
  uint64_t MaxOutputFileSize() const { return max_output_file_size_; }

-  // Whether compression will be enabled for compaction outputs
-  bool enable_compression() const { return enable_compression_; }
+  // What compression for output
+  CompressionType OutputCompressionType() const { return output_compression_; }
+
+  // Whether need to write output file to second DB path.
+  uint32_t GetOutputPathId() const { return output_path_id_; }
+
+  // Generate input_levels_ from inputs_
+  // Should be called when inputs_ is stable
+  void GenerateFileLevels();

  // Is this a trivial compaction that can be implemented by just
  // moving a single input file to the next level (no merging or splitting)
  bool IsTrivialMove() const;

+  // If true, then the comaction can be done by simply deleting input files.
+  bool IsDeletionCompaction() const {
+    return deletion_compaction_;
+  }
+
  // Add all inputs to this compaction as delete operations to *edit.
  void AddInputDeletions(VersionEdit* edit);

-  // Returns true if the information we have available guarantees that
-  // the compaction is producing data in "level+1" for which no data exists
-  // in levels greater than "level+1".
-  bool IsBaseLevelForKey(const Slice& user_key);
+  // Returns true if the available information we have guarantees that
+  // the input "user_key" does not exist in any level beyond "output_level()".
+  bool KeyNotExistsBeyondOutputLevel(const Slice& user_key);

  // Returns true iff we should stop building the current output
  // before processing "internal_key".
@@ -74,6 +134,9 @@ class Compaction {
  // Delete this compaction from the list of running compactions.
  void ReleaseCompactionFiles(Status status);

+  // Returns the summary of the compaction in "output" with maximum "len"
+  // in bytes.  The caller is responsible for the memory management of
+  // "output".
  void Summary(char* output, int len);

  // Return the score that was used to pick this compaction run.
@@ -88,40 +151,56 @@ class Compaction {
  // Was this compaction triggered manually by the client?
  bool IsManualCompaction() { return is_manual_compaction_; }

+  // Returns the size in bytes that the output file should be preallocated to.
+  // In level compaction, that is max_file_size_. In universal compaction, that
+  // is the sum of all input file sizes.
+  uint64_t OutputFilePreallocationSize();
+
 private:
  friend class CompactionPicker;
  friend class UniversalCompactionPicker;
+  friend class FIFOCompactionPicker;
  friend class LevelCompactionPicker;

-  Compaction(Version* input_version, int level, int out_level,
+  Compaction(Version* input_version, int start_level, int out_level,
             uint64_t target_file_size, uint64_t max_grandparent_overlap_bytes,
-             bool seek_compaction = false, bool enable_compression = true);
+             uint32_t output_path_id, CompressionType output_compression,
+             bool seek_compaction = false, bool deletion_compaction = false);

-  int level_;
-  int out_level_; // levels to which output files are stored
+  const int start_level_;    // the lowest level to be compacted
+  const int output_level_;  // levels to which output files are stored
  uint64_t max_output_file_size_;
  uint64_t max_grandparent_overlap_bytes_;
  Version* input_version_;
  VersionEdit* edit_;
  int number_levels_;
  ColumnFamilyData* cfd_;
+  Arena arena_;          // Arena used to allocate space for file_levels_

+  uint32_t output_path_id_;
+  CompressionType output_compression_;
  bool seek_compaction_;
-  bool enable_compression_;
+  // If true, then the comaction can be done by simply deleting input files.
+  bool deletion_compaction_;

-  // Each compaction reads inputs from "level_" and "level_+1"
-  std::vector<FileMetaData*> inputs_[2];      // The two sets of inputs
+  // Compaction input files organized by level.
+  autovector<CompactionInputFiles> inputs_;
+
+  // A copy of inputs_, organized more closely in memory
+  autovector<FileLevel, 2> input_levels_;

  // State used to check for number of of overlapping grandparent files
-  // (parent == level_ + 1, grandparent == level_ + 2)
+  // (grandparent == "output_level_ + 1")
+  // This vector is updated by Version::GetOverlappingInputs().
  std::vector<FileMetaData*> grandparents_;
-  size_t grandparent_index_;  // Index in grandparent_starts_
-  bool seen_key_;             // Some output key has been seen
+  size_t grandparent_index_;   // Index in grandparent_starts_
+  bool seen_key_;              // Some output key has been seen
  uint64_t overlapped_bytes_;  // Bytes of overlap between current output
-                              // and grandparent files
-  int base_index_;   // index of the file in files_[level_]
-  int parent_index_; // index of some file with same range in files_[level_+1]
-  double score_;     // score that was used to pick this compaction.
+                               // and grandparent files
+  int base_index_;    // index of the file in files_[start_level_]
+  int parent_index_;  // index of some file with same range in
+                      // files_[start_level_+1]
+  double score_;      // score that was used to pick this compaction.

  // Is this compaction creating a file in the bottom most level?
  bool bottommost_level_;
@@ -131,21 +210,28 @@ class Compaction {
  // Is this compaction requested by the client?
  bool is_manual_compaction_;

-  // level_ptrs_ holds indices into input_version_->levels_: our state
-  // is that we are positioned at one of the file ranges for each
-  // higher level than the ones involved in this compaction (i.e. for
-  // all L >= level_ + 2).
+  // "level_ptrs_" holds indices into "input_version_->levels_", where each
+  // index remembers which file of an associated level we are currently used
+  // to check KeyNotExistsBeyondOutputLevel() for deletion operation.
+  // As it is for checking KeyNotExistsBeyondOutputLevel(), it only
+  // records indices for all levels beyond "output_level_".
  std::vector<size_t> level_ptrs_;

  // mark (or clear) all files that are being compacted
-  void MarkFilesBeingCompacted(bool);
+  void MarkFilesBeingCompacted(bool mark_as_compacted);

-  // Initialize whether compaction producing files at the bottommost level
-  void SetupBottomMostLevel(bool isManual);
+  // Initialize whether the compaction is producing files at the
+  // bottommost level.
+  //
+  // @see BottomMostLevel()
+  void SetupBottomMostLevel(bool is_manual);

  // In case of compaction error, reset the nextIndex that is used
  // to pick up the next file to be compacted from files_by_size_
  void ResetNextCompactionIndex();
 };

+// Utility function
+extern uint64_t TotalFileSize(const std::vector<FileMetaData*>& files);
+
 }  // namespace rocksdb
@@ -9,22 +9,50 @@

 #include "db/compaction_picker.h"

+#define __STDC_FORMAT_MACROS
+#include <inttypes.h>
 #include <limits>
+#include "db/filename.h"
 #include "util/log_buffer.h"
 #include "util/statistics.h"

 namespace rocksdb {

-namespace {
-
-uint64_t TotalFileSize(const std::vector<FileMetaData*>& files) {
+uint64_t TotalCompensatedFileSize(const std::vector<FileMetaData*>& files) {
  uint64_t sum = 0;
  for (size_t i = 0; i < files.size() && files[i]; i++) {
-    sum += files[i]->file_size;
+    sum += files[i]->compensated_file_size;
  }
  return sum;
 }

+namespace {
+// Determine compression type, based on user options, level of the output
+// file and whether compression is disabled.
+// If enable_compression is false, then compression is always disabled no
+// matter what the values of the other two parameters are.
+// Otherwise, the compression type is determined based on options and level.
+CompressionType GetCompressionType(const Options& options, int level,
+                                   const bool enable_compression = true) {
+  if (!enable_compression) {
+    // disable compression
+    return kNoCompression;
+  }
+  // If the use has specified a different compression level for each level,
+  // then pick the compresison for that level.
+  if (!options.compression_per_level.empty()) {
+    const int n = options.compression_per_level.size() - 1;
+    // It is possible for level_ to be -1; in that case, we use level
+    // 0's compression.  This occurs mostly in backwards compatibility
+    // situations when the builder doesn't know what level the file
+    // belongs to.  Likewise, if level_ is beyond the end of the
+    // specified compression levels, use the last value.
+    return options.compression_per_level[std::max(0, std::min(level, n))];
+  } else {
+    return options.compression;
+  }
+}
+
 // Multiple two operands. If they overflow, return op1.
 uint64_t MultiplyCheckOverflow(uint64_t op1, int op2) {
  if (op1 == 0) {
@@ -78,7 +106,7 @@ void CompactionPicker::SizeBeingCompacted(std::vector<uint64_t>& sizes) {
    for (auto c : compactions_in_progress_[level]) {
      assert(c->level() == level);
      for (int i = 0; i < c->num_input_files(0); i++) {
-        total += c->input(0,i)->file_size;
+        total += c->input(0, i)->compensated_file_size;
      }
    }
    sizes[level] = total;
@@ -166,14 +194,15 @@ bool CompactionPicker::ExpandWhileOverlapping(Compaction* c) {
  size_t old_size;
  do {
    old_size = c->inputs_[0].size();
-    GetRange(c->inputs_[0], &smallest, &largest);
+    GetRange(c->inputs_[0].files, &smallest, &largest);
    c->inputs_[0].clear();
    c->input_version_->GetOverlappingInputs(
-        level, &smallest, &largest, &c->inputs_[0], hint_index, &hint_index);
+        level, &smallest, &largest, &c->inputs_[0].files,
+        hint_index, &hint_index);
  } while(c->inputs_[0].size() > old_size);

  // Get the new range
-  GetRange(c->inputs_[0], &smallest, &largest);
+  GetRange(c->inputs_[0].files, &smallest, &largest);

  // If, after the expansion, there are files that are already under
  // compaction, then we must drop/cancel this compaction.
@@ -183,7 +212,7 @@ bool CompactionPicker::ExpandWhileOverlapping(Compaction* c) {
        "[%s] ExpandWhileOverlapping() failure because zero input files",
        c->column_family_data()->GetName().c_str());
  }
-  if (c->inputs_[0].empty() || FilesInCompaction(c->inputs_[0]) ||
+  if (c->inputs_[0].empty() || FilesInCompaction(c->inputs_[0].files) ||
      (c->level() != c->output_level() &&
       ParentRangeInCompaction(c->input_version_, &smallest, &largest, level,
                               &parent_index))) {
@@ -239,16 +268,17 @@ void CompactionPicker::SetupOtherInputs(Compaction* c) {
  InternalKey smallest, largest;

  // Get the range one last time.
-  GetRange(c->inputs_[0], &smallest, &largest);
+  GetRange(c->inputs_[0].files, &smallest, &largest);

  // Populate the set of next-level files (inputs_[1]) to include in compaction
-  c->input_version_->GetOverlappingInputs(level + 1, &smallest, &largest,
-                                          &c->inputs_[1], c->parent_index_,
-                                          &c->parent_index_);
+  c->input_version_->GetOverlappingInputs(
+      level + 1, &smallest, &largest,
+      &c->inputs_[1].files, c->parent_index_,
+      &c->parent_index_);

  // Get entire range covered by compaction
  InternalKey all_start, all_limit;
-  GetRange(c->inputs_[0], c->inputs_[1], &all_start, &all_limit);
+  GetRange(c->inputs_[0].files, c->inputs_[1].files, &all_start, &all_limit);

  // See if we can further grow the number of inputs in "level" without
  // changing the number of "level+1" files we pick up. We also choose NOT
@@ -259,9 +289,9 @@ void CompactionPicker::SetupOtherInputs(Compaction* c) {
    std::vector<FileMetaData*> expanded0;
    c->input_version_->GetOverlappingInputs(
        level, &all_start, &all_limit, &expanded0, c->base_index_, nullptr);
-    const uint64_t inputs0_size = TotalFileSize(c->inputs_[0]);
-    const uint64_t inputs1_size = TotalFileSize(c->inputs_[1]);
-    const uint64_t expanded0_size = TotalFileSize(expanded0);
+    const uint64_t inputs0_size = TotalCompensatedFileSize(c->inputs_[0].files);
+    const uint64_t inputs1_size = TotalCompensatedFileSize(c->inputs_[1].files);
+    const uint64_t expanded0_size = TotalCompensatedFileSize(expanded0);
    uint64_t limit = ExpandedCompactionByteSizeLimit(level);
    if (expanded0.size() > c->inputs_[0].size() &&
        inputs1_size + expanded0_size < limit &&
@@ -276,19 +306,18 @@ void CompactionPicker::SetupOtherInputs(Compaction* c) {
      if (expanded1.size() == c->inputs_[1].size() &&
          !FilesInCompaction(expanded1)) {
        Log(options_->info_log,
-            "[%s] Expanding@%lu %lu+%lu (%lu+%lu bytes) to %lu+%lu (%lu+%lu "
-            "bytes)\n",
-            c->column_family_data()->GetName().c_str(), (unsigned long)level,
-            (unsigned long)(c->inputs_[0].size()),
-            (unsigned long)(c->inputs_[1].size()), (unsigned long)inputs0_size,
-            (unsigned long)inputs1_size, (unsigned long)(expanded0.size()),
-            (unsigned long)(expanded1.size()), (unsigned long)expanded0_size,
-            (unsigned long)inputs1_size);
+            "[%s] Expanding@%d %zu+%zu (%" PRIu64 "+%" PRIu64
+            " bytes) to %zu+%zu (%" PRIu64 "+%" PRIu64 "bytes)\n",
+            c->column_family_data()->GetName().c_str(), level,
+            c->inputs_[0].size(), c->inputs_[1].size(), inputs0_size,
+            inputs1_size, expanded0.size(), expanded1.size(), expanded0_size,
+            inputs1_size);
        smallest = new_start;
        largest = new_limit;
-        c->inputs_[0] = expanded0;
-        c->inputs_[1] = expanded1;
-        GetRange(c->inputs_[0], c->inputs_[1], &all_start, &all_limit);
+        c->inputs_[0].files = expanded0;
+        c->inputs_[1].files = expanded1;
+        GetRange(c->inputs_[0].files, c->inputs_[1].files,
+                 &all_start, &all_limit);
      }
    }
  }
@@ -301,12 +330,15 @@ void CompactionPicker::SetupOtherInputs(Compaction* c) {
  }
 }

-
 Compaction* CompactionPicker::CompactRange(Version* version, int input_level,
                                           int output_level,
+                                           uint32_t output_path_id,
                                           const InternalKey* begin,
                                           const InternalKey* end,
                                           InternalKey** compaction_end) {
+  // CompactionPickerFIFO has its own implementation of compact range
+  assert(options_->compaction_style != kCompactionStyleFIFO);
+
  std::vector<FileMetaData*> inputs;
  bool covering_the_whole_range = true;

@@ -330,7 +362,7 @@ Compaction* CompactionPicker::CompactRange(Version* version, int input_level,
        MaxFileSizeForLevel(input_level) * options_->source_compaction_factor;
    uint64_t total = 0;
    for (size_t i = 0; i + 1 < inputs.size(); ++i) {
-      uint64_t s = inputs[i]->file_size;
+      uint64_t s = inputs[i]->compensated_file_size;
      total += s;
      if (total >= limit) {
        **compaction_end = inputs[i + 1]->smallest;
@@ -340,11 +372,13 @@ Compaction* CompactionPicker::CompactRange(Version* version, int input_level,
      }
    }
  }
-  Compaction* c = new Compaction(version, input_level, output_level,
-                                 MaxFileSizeForLevel(output_level),
-                                 MaxGrandParentOverlapBytes(input_level));
+  assert(output_path_id < static_cast<uint32_t>(options_->db_paths.size()));
+  Compaction* c = new Compaction(
+      version, input_level, output_level, MaxFileSizeForLevel(output_level),
+      MaxGrandParentOverlapBytes(input_level), output_path_id,
+      GetCompressionType(*options_, output_level));

-  c->inputs_[0] = inputs;
+  c->inputs_[0].files = inputs;
  if (ExpandWhileOverlapping(c) == false) {
    delete c;
    Log(options_->info_log,
@@ -402,31 +436,6 @@ Compaction* LevelCompactionPicker::PickCompaction(Version* version,
    }
  }

-  // Find compactions needed by seeks
-  FileMetaData* f = version->file_to_compact_;
-  if (c == nullptr && f != nullptr && !f->being_compacted) {
-
-    level = version->file_to_compact_level_;
-    int parent_index = -1;
-
-    // Only allow one level 0 compaction at a time.
-    // Do not pick this file if its parents at level+1 are being compacted.
-    if (level != 0 || compactions_in_progress_[0].empty()) {
-      if (!ParentRangeInCompaction(version, &f->smallest, &f->largest, level,
-                                   &parent_index)) {
-        c = new Compaction(version, level, level + 1,
-                           MaxFileSizeForLevel(level + 1),
-                           MaxGrandParentOverlapBytes(level), true);
-        c->inputs_[0].push_back(f);
-        c->parent_index_ = parent_index;
-        c->input_version_->file_to_compact_ = nullptr;
-        if (ExpandWhileOverlapping(c) == false) {
-          return nullptr;
-        }
-      }
-    }
-  }
-
  if (c == nullptr) {
    return nullptr;
  }
@@ -436,18 +445,18 @@ Compaction* LevelCompactionPicker::PickCompaction(Version* version,
  if (level == 0) {
    assert(compactions_in_progress_[0].empty());
    InternalKey smallest, largest;
-    GetRange(c->inputs_[0], &smallest, &largest);
+    GetRange(c->inputs_[0].files, &smallest, &largest);
    // Note that the next call will discard the file we placed in
    // c->inputs_[0] earlier and replace it with an overlapping set
    // which will include the picked file.
    c->inputs_[0].clear();
    c->input_version_->GetOverlappingInputs(0, &smallest, &largest,
-                                            &c->inputs_[0]);
+                                            &c->inputs_[0].files);

    // If we include more L0 files in the same compaction run it can
    // cause the 'smallest' and 'largest' key to get extended to a
    // larger range. So, re-invoke GetRange to get the new key range
-    GetRange(c->inputs_[0], &smallest, &largest);
+    GetRange(c->inputs_[0].files, &smallest, &largest);
    if (ParentRangeInCompaction(c->input_version_, &smallest, &largest, level,
                                &c->parent_index_)) {
      delete c;
@@ -487,7 +496,8 @@ Compaction* LevelCompactionPicker::PickCompactionBySize(Version* version,
  assert(level >= 0);
  assert(level + 1 < NumberLevels());
  c = new Compaction(version, level, level + 1, MaxFileSizeForLevel(level + 1),
-                     MaxGrandParentOverlapBytes(level));
+                     MaxGrandParentOverlapBytes(level), 0,
+                     GetCompressionType(*options_, level + 1));
  c->score_ = score;

  // Pick the largest file in this level that is not already
@@ -502,11 +512,12 @@ Compaction* LevelCompactionPicker::PickCompactionBySize(Version* version,
    int index = file_size[i];
    FileMetaData* f = c->input_version_->files_[level][index];

-    // check to verify files are arranged in descending size
+    // Check to verify files are arranged in descending compensated size.
    assert((i == file_size.size() - 1) ||
           (i >= Version::number_of_files_to_sort_ - 1) ||
-           (f->file_size >=
-            c->input_version_->files_[level][file_size[i + 1]]->file_size));
+           (f->compensated_file_size >=
+            c->input_version_->files_[level][file_size[i + 1]]->
+                compensated_file_size));

    // do not pick a file to compact if it is being compacted
    // from n-1 level.
@@ -526,7 +537,7 @@ Compaction* LevelCompactionPicker::PickCompactionBySize(Version* version,
                                level, &parent_index)) {
      continue;
    }
-    c->inputs_[0].push_back(f);
+    c->inputs_[0].files.push_back(f);
    c->base_index_ = index;
    c->parent_index_ = parent_index;
    break;
@@ -606,19 +617,13 @@ Compaction* UniversalCompactionPicker::PickCompaction(Version* version,
    newerfile = f;
  }

-  // The files are sorted from newest first to oldest last.
-  std::vector<int>& file_by_time = c->input_version_->files_by_size_[level];
-
  // Is the earliest file part of this compaction?
-  int last_index = file_by_time[file_by_time.size()-1];
-  FileMetaData* last_file = c->input_version_->files_[level][last_index];
-  if (c->inputs_[0][c->inputs_[0].size()-1] == last_file) {
-    c->bottommost_level_ = true;
-  }
+  FileMetaData* last_file = c->input_version_->files_[level].back();
+  c->bottommost_level_ = c->inputs_[0].files.back() == last_file;

  // update statistics
-  MeasureTime(options_->statistics.get(), NUM_FILES_IN_SINGLE_COMPACTION,
-              c->inputs_[0].size());
+  MeasureTime(options_->statistics.get(),
+              NUM_FILES_IN_SINGLE_COMPACTION, c->inputs_[0].size());

  // mark all the files that are being compacted
  c->MarkFilesBeingCompacted(true);
@@ -634,6 +639,37 @@ Compaction* UniversalCompactionPicker::PickCompaction(Version* version,
  return c;
 }

+uint32_t UniversalCompactionPicker::GetPathId(const Options& options,
+                                              uint64_t file_size) {
+  // Two conditions need to be satisfied:
+  // (1) the target path needs to be able to hold the file's size
+  // (2) Total size left in this and previous paths need to be not
+  //     smaller than expected future file size before this new file is
+  //     compacted, which is estimated based on size_ratio.
+  // For example, if now we are compacting files of size (1, 1, 2, 4, 8),
+  // we will make sure the target file, probably with size of 16, will be
+  // placed in a path so that eventually when new files are generated and
+  // compacted to (1, 1, 2, 4, 8, 16), all those files can be stored in or
+  // before the path we chose.
+  //
+  // TODO(sdong): now the case of multiple column families is not
+  // considered in this algorithm. So the target size can be violated in
+  // that case. We need to improve it.
+  uint64_t accumulated_size = 0;
+  uint64_t future_size =
+      file_size * (100 - options.compaction_options_universal.size_ratio) / 100;
+  uint32_t p = 0;
+  for (; p < options.db_paths.size() - 1; p++) {
+    uint64_t target_size = options.db_paths[p].target_size;
+    if (target_size > file_size &&
+        accumulated_size + (target_size - file_size) > future_size) {
+      return p;
+    }
+    accumulated_size += target_size;
+  }
+  return p;
+}
+
 //
 // Consider compaction files based on their size differences with
 // the next file in time order.
@@ -649,12 +685,12 @@ Compaction* UniversalCompactionPicker::PickCompactionUniversalReadAmp(
    options_->compaction_options_universal.max_merge_width;

  // The files are sorted from newest first to oldest last.
-  std::vector<int>& file_by_time = version->files_by_size_[level];
+  const auto& files = version->files_[level];
+
  FileMetaData* f = nullptr;
  bool done = false;
  int start_index = 0;
  unsigned int candidate_count = 0;
-  assert(file_by_time.size() == version->files_[level].size());

  unsigned int max_files_to_compact = std::min(max_merge_width,
                                       max_number_of_files_to_compact);
@@ -662,40 +698,38 @@ Compaction* UniversalCompactionPicker::PickCompactionUniversalReadAmp(

  // Considers a candidate file only if it is smaller than the
  // total size accumulated so far.
-  for (unsigned int loop = 0; loop < file_by_time.size(); loop++) {
+  for (unsigned int loop = 0; loop < files.size(); loop++) {

    candidate_count = 0;

    // Skip files that are already being compacted
-    for (f = nullptr; loop < file_by_time.size(); loop++) {
-      int index = file_by_time[loop];
-      f = version->files_[level][index];
+    for (f = nullptr; loop < files.size(); loop++) {
+      f = files[loop];

      if (!f->being_compacted) {
        candidate_count = 1;
        break;
      }
-      LogToBuffer(
-          log_buffer, "[%s] Universal: file %lu[%d] being compacted, skipping",
-          version->cfd_->GetName().c_str(), (unsigned long)f->number, loop);
+      LogToBuffer(log_buffer, "[%s] Universal: file %" PRIu64
+                              "[%d] being compacted, skipping",
+                  version->cfd_->GetName().c_str(), f->fd.GetNumber(), loop);
      f = nullptr;
    }

    // This file is not being compacted. Consider it as the
    // first candidate to be compacted.
-    uint64_t candidate_size =  f != nullptr? f->file_size : 0;
+    uint64_t candidate_size =  f != nullptr? f->compensated_file_size : 0;
    if (f != nullptr) {
      LogToBuffer(
-          log_buffer, "[%s] Universal: Possible candidate file %lu[%d].",
-          version->cfd_->GetName().c_str(), (unsigned long)f->number, loop);
+          log_buffer, "[%s] Universal: Possible candidate file %s[%d].",
+          version->cfd_->GetName().c_str(),
+          FormatFileNumber(f->fd.GetNumber(), f->fd.GetPathId()).c_str(), loop);
    }

    // Check if the suceeding files need compaction.
-    for (unsigned int i = loop+1;
-         candidate_count < max_files_to_compact && i < file_by_time.size();
-         i++) {
-      int index = file_by_time[i];
-      FileMetaData* f = version->files_[level][index];
+    for (unsigned int i = loop + 1;
+         candidate_count < max_files_to_compact && i < files.size(); i++) {
+      FileMetaData* f = files[i];
      if (f->being_compacted) {
        break;
      }
@@ -706,13 +740,13 @@ Compaction* UniversalCompactionPicker::PickCompactionUniversalReadAmp(
      // kCompactionStopStyleSimilarSize, it's simply the size of the last
      // picked file.
      uint64_t sz = (candidate_size * (100L + ratio)) /100;
-      if (sz < f->file_size) {
+      if (sz < f->fd.GetFileSize()) {
        break;
      }
      if (options_->compaction_options_universal.stop_style == kCompactionStopStyleSimilarSize) {
        // Similar-size stopping rule: also check the last picked file isn't
        // far larger than the next candidate file.
-        sz = (f->file_size * (100L + ratio)) / 100;
+        sz = (f->fd.GetFileSize() * (100L + ratio)) / 100;
        if (sz < candidate_size) {
          // If the small file we've encountered begins a run of similar-size
          // files, we'll pick them up on a future iteration of the outer
@@ -720,9 +754,9 @@ Compaction* UniversalCompactionPicker::PickCompactionUniversalReadAmp(
          // by the last-resort read amp strategy which disregards size ratios.
          break;
        }
-        candidate_size = f->file_size;
+        candidate_size = f->compensated_file_size;
      } else { // default kCompactionStopStyleTotalSize
-        candidate_size += f->file_size;
+        candidate_size += f->compensated_file_size;
      }
      candidate_count++;
    }
@@ -734,13 +768,14 @@ Compaction* UniversalCompactionPicker::PickCompactionUniversalReadAmp(
      break;
    } else {
      for (unsigned int i = loop;
-           i < loop + candidate_count && i < file_by_time.size(); i++) {
-       int index = file_by_time[i];
-       FileMetaData* f = version->files_[level][index];
-       LogToBuffer(log_buffer,
-                   "[%s] Universal: Skipping file %lu[%d] with size %lu %d\n",
-                   version->cfd_->GetName().c_str(), (unsigned long)f->number,
-                   i, (unsigned long)f->file_size, f->being_compacted);
+           i < loop + candidate_count && i < files.size(); i++) {
+        FileMetaData* f = files[i];
+        LogToBuffer(log_buffer, "[%s] Universal: Skipping file %" PRIu64
+                                "[%d] with size %" PRIu64
+                                " (compensated size %" PRIu64 ") %d\n",
+                    version->cfd_->GetName().c_str(), f->fd.GetNumber(), i,
+                    f->fd.GetFileSize(), f->compensated_file_size,
+                    f->being_compacted);
      }
    }
  }
@@ -756,28 +791,36 @@ Compaction* UniversalCompactionPicker::PickCompactionUniversalReadAmp(
  if (ratio_to_compress >= 0) {
    uint64_t total_size = version->NumLevelBytes(level);
    uint64_t older_file_size = 0;
-    for (unsigned int i = file_by_time.size() - 1; i >= first_index_after;
-        i--) {
-      older_file_size += version->files_[level][file_by_time[i]]->file_size;
+    for (unsigned int i = files.size() - 1;
+         i >= first_index_after; i--) {
+      older_file_size += files[i]->fd.GetFileSize();
      if (older_file_size * 100L >= total_size * (long) ratio_to_compress) {
        enable_compression = false;
        break;
      }
    }
  }
-  Compaction* c =
-      new Compaction(version, level, level, MaxFileSizeForLevel(level),
-                     LLONG_MAX, false, enable_compression);
+
+  uint64_t estimated_total_size = 0;
+  for (unsigned int i = 0; i < first_index_after; i++) {
+    estimated_total_size += files[i]->fd.GetFileSize();
+  }
+  uint32_t path_id = GetPathId(*options_, estimated_total_size);
+
+  Compaction* c = new Compaction(
+      version, level, level, MaxFileSizeForLevel(level), LLONG_MAX, path_id,
+      GetCompressionType(*options_, level, enable_compression));
  c->score_ = score;

  for (unsigned int i = start_index; i < first_index_after; i++) {
-    int index = file_by_time[i];
-    FileMetaData* f = c->input_version_->files_[level][index];
-    c->inputs_[0].push_back(f);
+    FileMetaData* f = c->input_version_->files_[level][i];
+    c->inputs_[0].files.push_back(f);
    LogToBuffer(log_buffer,
-                "[%s] Universal: Picking file %lu[%d] with size %lu\n",
-                version->cfd_->GetName().c_str(), (unsigned long)f->number, i,
-                (unsigned long)f->file_size);
+                "[%s] Universal: Picking file %s[%d] "
+                "with size %" PRIu64 " (compensated size %" PRIu64 ")\n",
+                version->cfd_->GetName().c_str(),
+                FormatFileNumber(f->fd.GetNumber(), f->fd.GetPathId()).c_str(),
+                i, f->fd.GetFileSize(), f->compensated_file_size);
  }
  return c;
 }
@@ -797,8 +840,7 @@ Compaction* UniversalCompactionPicker::PickCompactionUniversalSizeAmp(
                     max_size_amplification_percent;

  // The files are sorted from newest first to oldest last.
-  std::vector<int>& file_by_time = version->files_by_size_[level];
-  assert(file_by_time.size() == version->files_[level].size());
+  const auto& files = version->files_[level];

  unsigned int candidate_count = 0;
  uint64_t candidate_size = 0;
@@ -806,16 +848,15 @@ Compaction* UniversalCompactionPicker::PickCompactionUniversalSizeAmp(
  FileMetaData* f = nullptr;

  // Skip files that are already being compacted
-  for (unsigned int loop = 0; loop < file_by_time.size() - 1; loop++) {
-    int index = file_by_time[loop];
-    f = version->files_[level][index];
+  for (unsigned int loop = 0; loop < files.size() - 1; loop++) {
+    f = files[loop];
    if (!f->being_compacted) {
      start_index = loop;         // Consider this as the first candidate.
      break;
    }
-    LogToBuffer(log_buffer,
-                "[%s] Universal: skipping file %lu[%d] compacted %s",
-                version->cfd_->GetName().c_str(), (unsigned long)f->number,
+    LogToBuffer(log_buffer, "[%s] Universal: skipping file %s[%d] compacted %s",
+                version->cfd_->GetName().c_str(),
+                FormatFileNumber(f->fd.GetNumber(), f->fd.GetPathId()).c_str(),
                loop, " cannot be a candidate to reduce size amp.\n");
    f = nullptr;
  }
@@ -823,23 +864,23 @@ Compaction* UniversalCompactionPicker::PickCompactionUniversalSizeAmp(
    return nullptr;             // no candidate files
  }

-  LogToBuffer(log_buffer, "[%s] Universal: First candidate file %lu[%d] %s",
-              version->cfd_->GetName().c_str(), (unsigned long)f->number,
+  LogToBuffer(log_buffer, "[%s] Universal: First candidate file %s[%d] %s",
+              version->cfd_->GetName().c_str(),
+              FormatFileNumber(f->fd.GetNumber(), f->fd.GetPathId()).c_str(),
              start_index, " to reduce size amp.\n");

  // keep adding up all the remaining files
-  for (unsigned int loop = start_index; loop < file_by_time.size() - 1;
-       loop++) {
-    int index = file_by_time[loop];
-    f = version->files_[level][index];
+  for (unsigned int loop = start_index; loop < files.size() - 1; loop++) {
+    f = files[loop];
    if (f->being_compacted) {
      LogToBuffer(
-          log_buffer, "[%s] Universal: Possible candidate file %lu[%d] %s.",
-          version->cfd_->GetName().c_str(), (unsigned long)f->number, loop,
+          log_buffer, "[%s] Universal: Possible candidate file %s[%d] %s.",
+          version->cfd_->GetName().c_str(),
+          FormatFileNumber(f->fd.GetNumber(), f->fd.GetPathId()).c_str(), loop,
          " is already being compacted. No size amp reduction possible.\n");
      return nullptr;
    }
-    candidate_size += f->file_size;
+    candidate_size += f->compensated_file_size;
    candidate_count++;
  }
  if (candidate_count == 0) {
@@ -847,43 +888,117 @@ Compaction* UniversalCompactionPicker::PickCompactionUniversalSizeAmp(
  }

  // size of earliest file
-  int index = file_by_time[file_by_time.size() - 1];
-  uint64_t earliest_file_size = version->files_[level][index]->file_size;
+  uint64_t earliest_file_size = files.back()->fd.GetFileSize();

  // size amplification = percentage of additional size
  if (candidate_size * 100 < ratio * earliest_file_size) {
    LogToBuffer(
        log_buffer,
-        "[%s] Universal: size amp not needed. newer-files-total-size %lu "
-        "earliest-file-size %lu",
-        version->cfd_->GetName().c_str(), (unsigned long)candidate_size,
-        (unsigned long)earliest_file_size);
+        "[%s] Universal: size amp not needed. newer-files-total-size %" PRIu64
+        "earliest-file-size %" PRIu64,
+        version->cfd_->GetName().c_str(), candidate_size, earliest_file_size);
    return nullptr;
  } else {
-    LogToBuffer(log_buffer,
-                "[%s] Universal: size amp needed. newer-files-total-size %lu "
-                "earliest-file-size %lu",
-                version->cfd_->GetName().c_str(), (unsigned long)candidate_size,
-                (unsigned long)earliest_file_size);
+    LogToBuffer(
+        log_buffer,
+        "[%s] Universal: size amp needed. newer-files-total-size %" PRIu64
+        "earliest-file-size %" PRIu64,
+        version->cfd_->GetName().c_str(), candidate_size, earliest_file_size);
  }
-  assert(start_index >= 0 && start_index < file_by_time.size() - 1);
+  assert(start_index >= 0 && start_index < files.size() - 1);
+
+  // Estimate total file size
+  uint64_t estimated_total_size = 0;
+  for (unsigned int loop = start_index; loop < files.size(); loop++) {
+    estimated_total_size += files[loop]->fd.GetFileSize();
+  }
+  uint32_t path_id = GetPathId(*options_, estimated_total_size);

  // create a compaction request
  // We always compact all the files, so always compress.
  Compaction* c =
      new Compaction(version, level, level, MaxFileSizeForLevel(level),
-                     LLONG_MAX, false, true);
+                     LLONG_MAX, path_id, GetCompressionType(*options_, level));
  c->score_ = score;
-  for (unsigned int loop = start_index; loop < file_by_time.size(); loop++) {
-    int index = file_by_time[loop];
-    f = c->input_version_->files_[level][index];
-    c->inputs_[0].push_back(f);
+  for (unsigned int loop = start_index; loop < files.size(); loop++) {
+    f = c->input_version_->files_[level][loop];
+    c->inputs_[0].files.push_back(f);
    LogToBuffer(log_buffer,
-                "[%s] Universal: size amp picking file %lu[%d] with size %lu",
-                version->cfd_->GetName().c_str(), (unsigned long)f->number,
-                index, (unsigned long)f->file_size);
+        "[%s] Universal: size amp picking file %" PRIu64 "[%d] "
+        "with size %" PRIu64 " (compensated size %" PRIu64 ")",
+        version->cfd_->GetName().c_str(),
+        f->fd.GetNumber(), loop,
+        f->fd.GetFileSize(), f->compensated_file_size);
  }
  return c;
 }

+Compaction* FIFOCompactionPicker::PickCompaction(Version* version,
+                                                 LogBuffer* log_buffer) {
+  assert(version->NumberLevels() == 1);
+  uint64_t total_size = 0;
+  for (const auto& file : version->files_[0]) {
+    total_size += file->compensated_file_size;
+  }
+
+  if (total_size <= options_->compaction_options_fifo.max_table_files_size ||
+      version->files_[0].size() == 0) {
+    // total size not exceeded
+    LogToBuffer(log_buffer,
+                "[%s] FIFO compaction: nothing to do. Total size %" PRIu64
+                ", max size %" PRIu64 "\n",
+                version->cfd_->GetName().c_str(), total_size,
+                options_->compaction_options_fifo.max_table_files_size);
+    return nullptr;
+  }
+
+  if (compactions_in_progress_[0].size() > 0) {
+    LogToBuffer(log_buffer,
+                "[%s] FIFO compaction: Already executing compaction. No need "
+                "to run parallel compactions since compactions are very fast",
+                version->cfd_->GetName().c_str());
+    return nullptr;
+  }
+
+  Compaction* c = new Compaction(version, 0, 0, 0, 0, 0, kNoCompression, false,
+                                 true /* is deletion compaction */);
+  // delete old files (FIFO)
+  for (auto ritr = version->files_[0].rbegin();
+       ritr != version->files_[0].rend(); ++ritr) {
+    auto f = *ritr;
+    total_size -= f->compensated_file_size;
+    c->inputs_[0].files.push_back(f);
+    char tmp_fsize[16];
+    AppendHumanBytes(f->fd.GetFileSize(), tmp_fsize, sizeof(tmp_fsize));
+    LogToBuffer(log_buffer, "[%s] FIFO compaction: picking file %" PRIu64
+                            " with size %s for deletion",
+                version->cfd_->GetName().c_str(), f->fd.GetNumber(), tmp_fsize);
+    if (total_size <= options_->compaction_options_fifo.max_table_files_size) {
+      break;
+    }
+  }
+
+  c->MarkFilesBeingCompacted(true);
+  compactions_in_progress_[0].insert(c);
+
+  return c;
+}
+
+Compaction* FIFOCompactionPicker::CompactRange(
+    Version* version, int input_level, int output_level,
+    uint32_t output_path_id, const InternalKey* begin, const InternalKey* end,
+    InternalKey** compaction_end) {
+  assert(input_level == 0);
+  assert(output_level == 0);
+  *compaction_end = nullptr;
+  LogBuffer log_buffer(InfoLogLevel::INFO_LEVEL, options_->info_log.get());
+  Compaction* c = PickCompaction(version, &log_buffer);
+  if (c != nullptr) {
+    assert(output_path_id < static_cast<uint32_t>(options_->db_paths.size()));
+    c->output_path_id_ = output_path_id;
+  }
+  log_buffer.FlushBufferToLog();
+  return c;
+}
+
 }  // namespace rocksdb
@@ -47,9 +47,15 @@ class CompactionPicker {
  // compaction_end will be set to nullptr.
  // Client is responsible for compaction_end storage -- when called,
  // *compaction_end should point to valid InternalKey!
-  Compaction* CompactRange(Version* version, int input_level, int output_level,
-                           const InternalKey* begin, const InternalKey* end,
-                           InternalKey** compaction_end);
+  virtual Compaction* CompactRange(Version* version, int input_level,
+                                   int output_level, uint32_t output_path_id,
+                                   const InternalKey* begin,
+                                   const InternalKey* end,
+                                   InternalKey** compaction_end);
+
+  // Given the current number of levels, returns the lowest allowed level
+  // for compaction input.
+  virtual int MaxInputLevel(int current_num_levels) const = 0;

  // Free up the files that participated in a compaction
  void ReleaseCompactionFiles(Compaction* c, Status status);
@@ -134,6 +140,11 @@ class UniversalCompactionPicker : public CompactionPicker {
  virtual Compaction* PickCompaction(Version* version,
                                     LogBuffer* log_buffer) override;

+  // The maxinum allowed input level.  Always return 0.
+  virtual int MaxInputLevel(int current_num_levels) const override {
+    return 0;
+  }
+
 private:
  // Pick Universal compaction to limit read amplification
  Compaction* PickCompactionUniversalReadAmp(Version* version, double score,
@@ -144,6 +155,10 @@ class UniversalCompactionPicker : public CompactionPicker {
  // Pick Universal compaction to limit space amplification.
  Compaction* PickCompactionUniversalSizeAmp(Version* version, double score,
                                             LogBuffer* log_buffer);
+
+  // Pick a path ID to place a newly generated file, with its estimated file
+  // size.
+  static uint32_t GetPathId(const Options& options, uint64_t file_size);
 };

 class LevelCompactionPicker : public CompactionPicker {
@@ -154,6 +169,12 @@ class LevelCompactionPicker : public CompactionPicker {
  virtual Compaction* PickCompaction(Version* version,
                                     LogBuffer* log_buffer) override;

+  // Returns current_num_levels - 2, meaning the last level cannot be
+  // compaction input level.
+  virtual int MaxInputLevel(int current_num_levels) const override {
+    return current_num_levels - 2;
+  }
+
 private:
  // For the specfied level, pick a compaction.
  // Returns nullptr if there is no compaction to be done.
@@ -162,4 +183,28 @@ class LevelCompactionPicker : public CompactionPicker {
  Compaction* PickCompactionBySize(Version* version, int level, double score);
 };

+class FIFOCompactionPicker : public CompactionPicker {
+ public:
+  FIFOCompactionPicker(const Options* options,
+                       const InternalKeyComparator* icmp)
+      : CompactionPicker(options, icmp) {}
+
+  virtual Compaction* PickCompaction(Version* version,
+                                     LogBuffer* log_buffer) override;
+
+  virtual Compaction* CompactRange(Version* version, int input_level,
+                                   int output_level, uint32_t output_path_id,
+                                   const InternalKey* begin,
+                                   const InternalKey* end,
+                                   InternalKey** compaction_end) override;
+
+  // The maxinum allowed input level.  Always return 0.
+  virtual int MaxInputLevel(int current_num_levels) const override {
+    return 0;
+  }
+};
+
+// Utility function
+extern uint64_t TotalCompensatedFileSize(const std::vector<FileMetaData*>& files);
+
 }  // namespace rocksdb
@@ -8,6 +8,20 @@
 // found in the LICENSE file. See the AUTHORS file for names of contributors.

 #define __STDC_FORMAT_MACROS
+
+#ifndef GFLAGS
+#include <cstdio>
+int main() {
+  fprintf(stderr, "Please install gflags to run rocksdb tools\n");
+  return 1;
+}
+#else
+
+#ifdef NUMA
+#include <numa.h>
+#include <numaif.h>
+#endif
+
 #include <inttypes.h>
 #include <cstddef>
 #include <sys/types.h>
@@ -16,7 +30,6 @@
 #include <gflags/gflags.h>
 #include "db/db_impl.h"
 #include "db/version_set.h"
-#include "rocksdb/statistics.h"
 #include "rocksdb/options.h"
 #include "rocksdb/cache.h"
 #include "rocksdb/db.h"
@@ -40,6 +53,9 @@
 #include "hdfs/env_hdfs.h"
 #include "utilities/merge_operators.h"

+using GFLAGS::ParseCommandLineFlags;
+using GFLAGS::RegisterFlagValidator;
+using GFLAGS::SetUsageMessage;

 DEFINE_string(benchmarks,
              "fillseq,"
@@ -147,14 +163,7 @@ DEFINE_int32(duration, 0, "Time in seconds for the random-ops tests to run."
 DEFINE_int32(value_size, 100, "Size of each value");


-// the maximum size of key in bytes
-static const int kMaxKeySize = 128;
 static bool ValidateKeySize(const char* flagname, int32_t value) {
-  if (value > kMaxKeySize) {
-    fprintf(stderr, "Invalid value for --%s: %d, must be < %d\n",
-            flagname, value, kMaxKeySize);
-    return false;
-  }
  return true;
 }

@@ -168,6 +177,14 @@ DEFINE_double(compression_ratio, 0.5, "Arrange to generate values that shrink"

 DEFINE_bool(histogram, false, "Print histogram of operation timings");

+DEFINE_bool(enable_numa, false,
+            "Make operations aware of NUMA architecture and bind memory "
+            "and cpus corresponding to nodes together. In NUMA, memory "
+            "in same node as CPUs are closer when compared to memory in "
+            "other nodes. Reads can be faster when the process is bound to "
+            "CPU and memory of same node. Use \"$numactl --hardware\" command "
+            "to see NUMA memory architecture.");
+
 DEFINE_int64(write_buffer_size, rocksdb::Options().write_buffer_size,
             "Number of bytes to buffer in memtable before compacting");

@@ -224,6 +241,10 @@ DEFINE_int64(cache_size, -1, "Number of bytes to use as a cache of uncompressed"
 DEFINE_int32(block_size, rocksdb::Options().block_size,
             "Number of bytes in a block.");

+DEFINE_int32(block_restart_interval, rocksdb::Options().block_restart_interval,
+             "Number of keys between restart points "
+             "for delta encoding of keys.");
+
 DEFINE_int64(compressed_cache_size, -1,
             "Number of bytes to use as a cache of compressed data.");

@@ -328,9 +349,6 @@ DEFINE_int32(deletepercent, 2, "Percentage of deletes out of reads/writes/"
             "deletepercent), so deletepercent must be smaller than (100 - "
             "FLAGS_readwritepercent)");

-DEFINE_int32(disable_seek_compaction, false, "Option to disable compaction"
-             " triggered by read.");
-
 DEFINE_uint64(delete_obsolete_files_period_micros, 0, "Option to delete "
              "obsolete files periodically. 0 means that obsolete files are"
              " deleted after every compaction run.");
@@ -376,8 +394,7 @@ static bool ValidateCompressionLevel(const char* flagname, int32_t value) {
 }

 static const bool FLAGS_compression_level_dummy __attribute__((unused)) =
-    google::RegisterFlagValidator(&FLAGS_compression_level,
-                                  &ValidateCompressionLevel);
+    RegisterFlagValidator(&FLAGS_compression_level, &ValidateCompressionLevel);

 DEFINE_int32(min_level_to_compress, -1, "If non-negative, compression starts"
             " from this level. Levels with number < min_level_to_compress are"
@@ -461,6 +478,8 @@ static auto FLAGS_compaction_fadvice_e =

 DEFINE_bool(use_tailing_iterator, false,
            "Use tailing iterator to access a series of keys instead of get");
+DEFINE_int64(iter_refresh_interval_us, -1,
+             "How often to refresh iterators. Disable refresh when -1");

 DEFINE_bool(use_adaptive_mutex, rocksdb::Options().use_adaptive_mutex,
            "Use adaptive mutex");
@@ -522,6 +541,9 @@ DEFINE_string(memtablerep, "skip_list", "");
 DEFINE_int64(hash_bucket_count, 1024 * 1024, "hash bucket count");
 DEFINE_bool(use_plain_table, false, "if use plain table "
            "instead of block-based table format");
+DEFINE_bool(use_hash_search, false, "if use kHashSearch "
+            "instead of kBinarySearch. "
+            "This is valid if only we use BlockTable");

 DEFINE_string(merge_operator, "", "The merge operator to use with the database."
              "If a new merge operator is specified, be sure to use fresh"
@@ -529,33 +551,32 @@ DEFINE_string(merge_operator, "", "The merge operator to use with the database."
              " utilities/merge_operators.h");

 static const bool FLAGS_soft_rate_limit_dummy __attribute__((unused)) =
-  google::RegisterFlagValidator(&FLAGS_soft_rate_limit,
-                                &ValidateRateLimit);
+    RegisterFlagValidator(&FLAGS_soft_rate_limit, &ValidateRateLimit);

 static const bool FLAGS_hard_rate_limit_dummy __attribute__((unused)) =
-  google::RegisterFlagValidator(&FLAGS_hard_rate_limit, &ValidateRateLimit);
+    RegisterFlagValidator(&FLAGS_hard_rate_limit, &ValidateRateLimit);

 static const bool FLAGS_prefix_size_dummy __attribute__((unused)) =
-  google::RegisterFlagValidator(&FLAGS_prefix_size, &ValidatePrefixSize);
+    RegisterFlagValidator(&FLAGS_prefix_size, &ValidatePrefixSize);

 static const bool FLAGS_key_size_dummy __attribute__((unused)) =
-  google::RegisterFlagValidator(&FLAGS_key_size, &ValidateKeySize);
+    RegisterFlagValidator(&FLAGS_key_size, &ValidateKeySize);

 static const bool FLAGS_cache_numshardbits_dummy __attribute__((unused)) =
-  google::RegisterFlagValidator(&FLAGS_cache_numshardbits,
-                                &ValidateCacheNumshardbits);
+    RegisterFlagValidator(&FLAGS_cache_numshardbits,
+                          &ValidateCacheNumshardbits);

 static const bool FLAGS_readwritepercent_dummy __attribute__((unused)) =
-  google::RegisterFlagValidator(&FLAGS_readwritepercent,
-                                &ValidateInt32Percent);
+    RegisterFlagValidator(&FLAGS_readwritepercent, &ValidateInt32Percent);
+
+DEFINE_int32(disable_seek_compaction, false,
+             "Not used, left here for backwards compatibility");

 static const bool FLAGS_deletepercent_dummy __attribute__((unused)) =
-  google::RegisterFlagValidator(&FLAGS_deletepercent,
-                                &ValidateInt32Percent);
-static const bool
-  FLAGS_table_cache_numshardbits_dummy __attribute__((unused)) =
-  google::RegisterFlagValidator(&FLAGS_table_cache_numshardbits,
-                                &ValidateTableCacheNumshardbits);
+    RegisterFlagValidator(&FLAGS_deletepercent, &ValidateInt32Percent);
+static const bool FLAGS_table_cache_numshardbits_dummy __attribute__((unused)) =
+    RegisterFlagValidator(&FLAGS_table_cache_numshardbits,
+                          &ValidateTableCacheNumshardbits);

 namespace rocksdb {

@@ -582,9 +603,9 @@ class RandomGenerator {
  }

  Slice Generate(unsigned int len) {
+    assert(len <= data_.size());
    if (pos_ + len > data_.size()) {
      pos_ = 0;
-      assert(len < data_.size());
    }
    pos_ += len;
    return Slice(data_.data() + pos_ - len, len);
@@ -662,7 +683,7 @@ class Stats {
  void SetId(int id) { id_ = id; }
  void SetExcludeFromMerge() { exclude_from_merge_ = true; }

-  void FinishedSingleOp(DB* db) {
+  void FinishedOps(DB* db, int64_t num_ops) {
    if (FLAGS_histogram) {
      double now = FLAGS_env->NowMicros();
      double micros = now - last_op_finish_;
@@ -674,7 +695,7 @@ class Stats {
      last_op_finish_ = now;
    }

-    done_++;
+    done_ += num_ops;
    if (done_ >= next_report_) {
      if (!FLAGS_stats_interval) {
        if      (next_report_ < 1000)   next_report_ += 100;
@@ -720,7 +741,7 @@ class Stats {

  void Report(const Slice& name) {
    // Pretend at least one op was done in case we are running a benchmark
-    // that does not call FinishedSingleOp().
+    // that does not call FinishedOps().
    if (done_ < 1) done_ = 1;

    std::string extra;
@@ -835,6 +856,15 @@ class Benchmark {
  int64_t writes_;
  int64_t readwrites_;
  int64_t merge_keys_;
+
+  bool SanityCheck() {
+    if (FLAGS_compression_ratio > 1) {
+      fprintf(stderr, "compression_ratio should be between 0 and 1\n");
+      return false;
+    }
+    return true;
+  }
+
  void PrintHeader() {
    PrintEnvironment();
    fprintf(stdout, "Keys:       %d bytes each\n", FLAGS_key_size);
@@ -852,6 +882,18 @@ class Benchmark {
              * num_)
             / 1048576.0));
    fprintf(stdout, "Write rate limit: %d\n", FLAGS_writes_per_second);
+    if (FLAGS_enable_numa) {
+      fprintf(stderr, "Running in NUMA enabled mode.\n");
+#ifndef NUMA
+      fprintf(stderr, "NUMA is not defined in the system.\n");
+      exit(1);
+#else
+      if (numa_available() == -1) {
+        fprintf(stderr, "NUMA is not supported by the system.\n");
+        exit(1);
+      }
+#endif
+    }
    switch (FLAGS_compression_type_e) {
      case rocksdb::kNoCompression:
        fprintf(stdout, "Compression: none\n");
@@ -1114,6 +1156,9 @@ class Benchmark {
  }

  void Run() {
+    if (!SanityCheck()) {
+      exit(1);
+    }
    PrintHeader();
    Open();
    const char* benchmarks = FLAGS_benchmarks.c_str();
@@ -1334,7 +1379,25 @@ class Benchmark {
    shared.start = false;

    ThreadArg* arg = new ThreadArg[n];
+
    for (int i = 0; i < n; i++) {
+#ifdef NUMA
+      if (FLAGS_enable_numa) {
+        // Performs a local allocation of memory to threads in numa node.
+        int n_nodes = numa_num_task_nodes();  // Number of nodes in NUMA.
+        numa_exit_on_error = 1;
+        int numa_node = i % n_nodes;
+        bitmask* nodes = numa_allocate_nodemask();
+        numa_bitmask_clearall(nodes);
+        numa_bitmask_setbit(nodes, numa_node);
+        // numa_bind() call binds the process to the node and these
+        // properties are passed on to the thread that is created in
+        // StartThread method called later in the loop.
+        numa_bind(nodes);
+        numa_set_strict(1);
+        numa_free_nodemask(nodes);
+      }
+#endif
      arg[i].bm = this;
      arg[i].method = method;
      arg[i].shared = &shared;
@@ -1377,7 +1440,7 @@ class Benchmark {
    uint32_t crc = 0;
    while (bytes < 500 * 1048576) {
      crc = crc32c::Value(data.data(), size);
-      thread->stats.FinishedSingleOp(nullptr);
+      thread->stats.FinishedOps(nullptr, 1);
      bytes += size;
    }
    // Print so result is not dead
@@ -1396,7 +1459,7 @@ class Benchmark {
    unsigned int xxh32 = 0;
    while (bytes < 500 * 1048576) {
      xxh32 = XXH32(data.data(), size, 0);
-      thread->stats.FinishedSingleOp(nullptr);
+      thread->stats.FinishedOps(nullptr, 1);
      bytes += size;
    }
    // Print so result is not dead
@@ -1417,7 +1480,7 @@ class Benchmark {
        ptr = ap.Acquire_Load();
      }
      count++;
-      thread->stats.FinishedSingleOp(nullptr);
+      thread->stats.FinishedOps(nullptr, 1);
    }
    if (ptr == nullptr) exit(1); // Disable unused variable warning.
  }
@@ -1458,7 +1521,7 @@ class Benchmark {
      }
      produced += compressed.size();
      bytes += input.size();
-      thread->stats.FinishedSingleOp(nullptr);
+      thread->stats.FinishedOps(nullptr, 1);
    }

    if (!ok) {
@@ -1539,7 +1602,7 @@ class Benchmark {
      }
      delete[] uncompressed;
      bytes += input.size();
-      thread->stats.FinishedSingleOp(nullptr);
+      thread->stats.FinishedOps(nullptr, 1);
    }

    if (!ok) {
@@ -1566,8 +1629,9 @@ class Benchmark {
    options.max_background_flushes = FLAGS_max_background_flushes;
    options.compaction_style = FLAGS_compaction_style_e;
    options.block_size = FLAGS_block_size;
+    options.block_restart_interval = FLAGS_block_restart_interval;
    options.filter_policy = filter_policy_;
-    if (FLAGS_use_plain_table) {
+    if (FLAGS_prefix_size != 0) {
      options.prefix_extractor.reset(
          NewFixedPrefixTransform(FLAGS_prefix_size));
    }
@@ -1628,8 +1692,27 @@ class Benchmark {
      if (bloom_bits_per_key < 0) {
        bloom_bits_per_key = 0;
      }
+
+      PlainTableOptions plain_table_options;
+      plain_table_options.user_key_len = FLAGS_key_size;
+      plain_table_options.bloom_bits_per_key = bloom_bits_per_key;
+      plain_table_options.hash_table_ratio = 0.75;
      options.table_factory = std::shared_ptr<TableFactory>(
-          NewPlainTableFactory(FLAGS_key_size, bloom_bits_per_key, 0.75));
+          NewPlainTableFactory(plain_table_options));
+    } else {
+      BlockBasedTableOptions block_based_options;
+      if (FLAGS_use_hash_search) {
+        if (FLAGS_prefix_size == 0) {
+          fprintf(stderr,
+              "prefix_size not assigned when enable use_hash_search \n");
+          exit(1);
+        }
+        block_based_options.index_type = BlockBasedTableOptions::kHashSearch;
+      } else {
+        block_based_options.index_type = BlockBasedTableOptions::kBinarySearch;
+      }
+      options.table_factory.reset(
+          NewBlockBasedTableFactory(block_based_options));
    }
    if (FLAGS_max_bytes_for_level_multiplier_additional_v.size() > 0) {
      if (FLAGS_max_bytes_for_level_multiplier_additional_v.size() !=
@@ -1661,7 +1744,6 @@ class Benchmark {
        options.compression_per_level[i] = FLAGS_compression_type_e;
      }
    }
-    options.disable_seek_compaction = FLAGS_disable_seek_compaction;
    options.delete_obsolete_files_period_micros =
      FLAGS_delete_obsolete_files_period_micros;
    options.soft_rate_limit = FLAGS_soft_rate_limit;
@@ -1849,9 +1931,9 @@ class Benchmark {
        GenerateKeyFromInt(key_gens[id]->Next(), FLAGS_num, &key);
        batch.Put(key, gen.Generate(value_size_));
        bytes += value_size_ + key_size_;
-        thread->stats.FinishedSingleOp(db_to_write);
      }
      s = db_to_write->Write(write_options_, &batch);
+      thread->stats.FinishedOps(db_to_write, entries_per_batch_);
      if (!s.ok()) {
        fprintf(stderr, "put error: %s\n", s.ToString().c_str());
        exit(1);
@@ -1876,7 +1958,7 @@ class Benchmark {
    int64_t bytes = 0;
    for (iter->SeekToFirst(); i < reads_ && iter->Valid(); iter->Next()) {
      bytes += iter->key().size() + iter->value().size();
-      thread->stats.FinishedSingleOp(db);
+      thread->stats.FinishedOps(db, 1);
      ++i;
    }
    delete iter;
@@ -1899,7 +1981,7 @@ class Benchmark {
    int64_t bytes = 0;
    for (iter->SeekToLast(); i < reads_ && iter->Valid(); iter->Prev()) {
      bytes += iter->key().size() + iter->value().size();
-      thread->stats.FinishedSingleOp(db_);
+      thread->stats.FinishedOps(db_, 1);
      ++i;
    }
    delete iter;
@@ -1922,11 +2004,11 @@ class Benchmark {
      if (db->Get(options, key, &value).ok()) {
        found++;
      }
-      thread->stats.FinishedSingleOp(db_);
+      thread->stats.FinishedOps(db_, 1);
    }

    char msg[100];
-    snprintf(msg, sizeof(msg), "(%" PRIu64 " of %" PRIu64 " found)",
+    snprintf(msg, sizeof(msg), "(%" PRIu64 " of %" PRIu64 " found)\n",
             found, read);

    thread->stats.AddMessage(msg);
@@ -1982,7 +2064,7 @@ class Benchmark {
      DB* db = SelectDB(thread);
      Iterator* iter = db->NewIterator(options);
      delete iter;
-      thread->stats.FinishedSingleOp(db);
+      thread->stats.FinishedOps(db, 1);
    }
  }

@@ -2009,12 +2091,31 @@ class Benchmark {
        multi_iters.push_back(db->NewIterator(options));
      }
    }
+    uint64_t last_refresh = FLAGS_env->NowMicros();

    Slice key = AllocateKey();
    std::unique_ptr<const char[]> key_guard(key.data());

    Duration duration(FLAGS_duration, reads_);
    while (!duration.Done(1)) {
+      if (!FLAGS_use_tailing_iterator && FLAGS_iter_refresh_interval_us >= 0) {
+        uint64_t now = FLAGS_env->NowMicros();
+        if (now - last_refresh > (uint64_t)FLAGS_iter_refresh_interval_us) {
+          if (db_ != nullptr) {
+            delete single_iter;
+            single_iter = db_->NewIterator(options);
+          } else {
+            for (auto iter : multi_iters) {
+              delete iter;
+            }
+            multi_iters.clear();
+            for (DB* db : multi_dbs_) {
+              multi_iters.push_back(db->NewIterator(options));
+            }
+          }
+        }
+        last_refresh = now;
+      }
      // Pick a Iterator to use
      Iterator* iter_to_use = single_iter;
      if (single_iter == nullptr) {
@@ -2027,7 +2128,7 @@ class Benchmark {
      if (iter_to_use->Valid() && iter_to_use->key().compare(key) == 0) {
        found++;
      }
-      thread->stats.FinishedSingleOp(db_);
+      thread->stats.FinishedOps(db_, 1);
    }
    delete single_iter;
    for (auto iter : multi_iters) {
@@ -2035,9 +2136,12 @@ class Benchmark {
    }

    char msg[100];
-    snprintf(msg, sizeof(msg), "(%" PRIu64 " of %" PRIu64 " found)",
+    snprintf(msg, sizeof(msg), "(%" PRIu64 " of %" PRIu64 " found)\n",
             found, read);
    thread->stats.AddMessage(msg);
+    if (FLAGS_perf_level > 0) {
+      thread->stats.AddMessage(perf_context.ToString());
+    }
  }

  void SeekRandomWhileWriting(ThreadState* thread) {
@@ -2062,9 +2166,9 @@ class Benchmark {
        const int64_t k = seq ? i + j : (thread->rand.Next() % FLAGS_num);
        GenerateKeyFromInt(k, FLAGS_num, &key);
        batch.Delete(key);
-        thread->stats.FinishedSingleOp(db);
      }
      auto s = db->Write(write_options_, &batch);
+      thread->stats.FinishedOps(db, entries_per_batch_);
      if (!s.ok()) {
        fprintf(stderr, "del error: %s\n", s.ToString().c_str());
        exit(1);
@@ -2124,7 +2228,7 @@ class Benchmark {
        fprintf(stderr, "put error: %s\n", s.ToString().c_str());
        exit(1);
      }
-      thread->stats.FinishedSingleOp(db_);
+      thread->stats.FinishedOps(db_, 1);

      ++num_writes;
      if (writes_per_second_by_10 && num_writes >= writes_per_second_by_10) {
@@ -2284,7 +2388,7 @@ class Benchmark {
        deletes_done++;
      }

-      thread->stats.FinishedSingleOp(db_);
+      thread->stats.FinishedOps(db_, 1);
    }
    char msg[100];
    snprintf(msg, sizeof(msg),
@@ -2342,7 +2446,7 @@ class Benchmark {
        put_weight--;
        writes_done++;
      }
-      thread->stats.FinishedSingleOp(db);
+      thread->stats.FinishedOps(db, 1);
    }
    char msg[100];
    snprintf(msg, sizeof(msg), "( reads:%" PRIu64 " writes:%" PRIu64 \
@@ -2376,7 +2480,7 @@ class Benchmark {
        fprintf(stderr, "put error: %s\n", s.ToString().c_str());
        exit(1);
      }
-      thread->stats.FinishedSingleOp(db);
+      thread->stats.FinishedOps(db, 1);
    }
    char msg[100];
    snprintf(msg, sizeof(msg),
@@ -2423,7 +2527,7 @@ class Benchmark {
        fprintf(stderr, "put error: %s\n", s.ToString().c_str());
        exit(1);
      }
-      thread->stats.FinishedSingleOp(db_);
+      thread->stats.FinishedOps(db_, 1);
    }

    char msg[100];
@@ -2459,7 +2563,7 @@ class Benchmark {
        fprintf(stderr, "merge error: %s\n", s.ToString().c_str());
        exit(1);
      }
-      thread->stats.FinishedSingleOp(db_);
+      thread->stats.FinishedOps(db_, 1);
    }

    // Print some statistics
@@ -2520,7 +2624,7 @@ class Benchmark {

      }

-      thread->stats.FinishedSingleOp(db_);
+      thread->stats.FinishedOps(db_, 1);
    }

    char msg[100];
@@ -2561,9 +2665,9 @@ class Benchmark {

 int main(int argc, char** argv) {
  rocksdb::port::InstallStackTraceHandler();
-  google::SetUsageMessage(std::string("\nUSAGE:\n") + std::string(argv[0]) +
-                          " [OPTIONS]...");
-  google::ParseCommandLineFlags(&argc, &argv, true);
+  SetUsageMessage(std::string("\nUSAGE:\n") + std::string(argv[0]) +
+                  " [OPTIONS]...");
+  ParseCommandLineFlags(&argc, &argv, true);

  FLAGS_compaction_style_e = (rocksdb::CompactionStyle) FLAGS_compaction_style;
  if (FLAGS_statistics) {
@@ -2614,3 +2718,5 @@ int main(int argc, char** argv) {
  benchmark.Run();
  return 0;
 }
+
+#endif  // GFLAGS
@@ -29,8 +29,11 @@ Status DBImpl::DisableFileDeletions() {
  MutexLock l(&mutex_);
  ++disable_delete_obsolete_files_;
  if (disable_delete_obsolete_files_ == 1) {
-    // if not, it has already been disabled, so don't log anything
    Log(options_.info_log, "File Deletions Disabled");
+  } else {
+    Log(options_.info_log,
+        "File Deletions Disabled, but already disabled. Counter: %d",
+        disable_delete_obsolete_files_);
  }
  return Status::OK();
 }
@@ -50,6 +53,10 @@ Status DBImpl::EnableFileDeletions(bool force) {
      Log(options_.info_log, "File Deletions Enabled");
      should_purge_files = true;
      FindObsoleteFiles(deletion_state, true);
+    } else {
+      Log(options_.info_log,
+          "File Deletions Enable, but not really enabled. Counter: %d",
+          disable_delete_obsolete_files_);
    }
  }
  if (should_purge_files)  {
@@ -91,7 +98,7 @@ Status DBImpl::GetLiveFiles(std::vector<std::string>& ret,
  }

  // Make a set of all of the live *.sst files
-  std::set<uint64_t> live;
+  std::vector<FileDescriptor> live;
  for (auto cfd : *versions_->GetColumnFamilySet()) {
    cfd->current()->AddLiveFiles(&live);
  }
@@ -102,7 +109,7 @@ Status DBImpl::GetLiveFiles(std::vector<std::string>& ret,
  // create names of the live files. The names are not absolute
  // paths, instead they are relative to dbname_;
  for (auto live_file : live) {
-    ret.push_back(TableFileName("", live_file));
+    ret.push_back(MakeTableFileName("", live_file.GetNumber()));
  }

  ret.push_back(CurrentFileName(""));
@@ -10,6 +10,7 @@

 #include <atomic>
 #include <deque>
+#include <limits>
 #include <set>
 #include <utility>
 #include <vector>
@@ -27,7 +28,7 @@
 #include "rocksdb/memtablerep.h"
 #include "rocksdb/transaction_log.h"
 #include "util/autovector.h"
-#include "util/stats_logger.h"
+#include "util/stop_watch.h"
 #include "util/thread_local.h"
 #include "db/internal_stats.h"

@@ -39,6 +40,7 @@ class Version;
 class VersionEdit;
 class VersionSet;
 class CompactionFilterV2;
+class Arena;

 class DBImpl : public DB {
 public:
@@ -94,13 +96,17 @@ class DBImpl : public DB {
  using DB::GetProperty;
  virtual bool GetProperty(ColumnFamilyHandle* column_family,
                           const Slice& property, std::string* value);
+  using DB::GetIntProperty;
+  virtual bool GetIntProperty(ColumnFamilyHandle* column_family,
+                              const Slice& property, uint64_t* value) override;
  using DB::GetApproximateSizes;
  virtual void GetApproximateSizes(ColumnFamilyHandle* column_family,
                                   const Range* range, int n, uint64_t* sizes);
  using DB::CompactRange;
  virtual Status CompactRange(ColumnFamilyHandle* column_family,
                              const Slice* begin, const Slice* end,
-                              bool reduce_level = false, int target_level = -1);
+                              bool reduce_level = false, int target_level = -1,
+                              uint32_t target_path_id = 0);

  using DB::NumberLevels;
  virtual int NumberLevels(ColumnFamilyHandle* column_family);
@@ -143,8 +149,8 @@ class DBImpl : public DB {
  virtual Status GetDbIdentity(std::string& identity);

  Status RunManualCompaction(ColumnFamilyData* cfd, int input_level,
-                             int output_level, const Slice* begin,
-                             const Slice* end);
+                             int output_level, uint32_t output_path_id,
+                             const Slice* begin, const Slice* end);

 #ifndef ROCKSDB_LITE
  // Extra methods (for testing) that are not in the public DB interface
@@ -197,6 +203,17 @@ class DBImpl : public DB {
  Status TEST_ReadFirstLine(const std::string& fname, SequenceNumber* sequence);
 #endif  // NDEBUG

+  // Structure to store information for candidate files to delete.
+  struct CandidateFileInfo {
+    std::string file_name;
+    uint32_t path_id;
+    CandidateFileInfo(std::string name, uint32_t path)
+        : file_name(name), path_id(path) {}
+    bool operator==(const CandidateFileInfo& other) const {
+      return file_name == other.file_name && path_id == other.path_id;
+    }
+  };
+
  // needed for CleanupIteratorState
  struct DeletionState {
    inline bool HaveSomethingToDelete() const {
@@ -208,10 +225,10 @@ class DBImpl : public DB {
    // a list of all files that we'll consider deleting
    // (every once in a while this is filled up with all files
    // in the DB directory)
-    std::vector<std::string> candidate_files;
+    std::vector<CandidateFileInfo> candidate_files;

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

    // a list of sst files that we need to delete
    std::vector<FileMetaData*> sst_delete_files;
@@ -276,15 +293,18 @@ class DBImpl : public DB {
  const std::string dbname_;
  unique_ptr<VersionSet> versions_;
  const DBOptions options_;
+  Statistics* stats_;

  Iterator* NewInternalIterator(const ReadOptions&, ColumnFamilyData* cfd,
-                                SuperVersion* super_version);
+                                SuperVersion* super_version,
+                                Arena* arena = nullptr);

 private:
  friend class DB;
  friend class InternalStats;
 #ifndef ROCKSDB_LITE
  friend class TailingIterator;
+  friend class ForwardIterator;
 #endif
  friend struct SuperVersion;
  struct CompactionState;
@@ -331,7 +351,8 @@ class DBImpl : public DB {
  Status MakeRoomForWrite(ColumnFamilyData* cfd,
                          bool force /* flush even if there is room? */,
                          autovector<SuperVersion*>* superversions_to_free,
-                          autovector<log::Writer*>* logs_to_free);
+                          autovector<log::Writer*>* logs_to_free,
+                          uint64_t expiration_time);

  void BuildBatchGroup(Writer** last_writer,
                       autovector<WriteBatch*>* write_batch_group);
@@ -342,12 +363,8 @@ class DBImpl : public DB {
  // Wait for memtable flushed
  Status WaitForFlushMemTable(ColumnFamilyData* cfd);

-  void MaybeScheduleLogDBDeployStats();
-
-#ifndef ROCKSDB_LITE
-  static void BGLogDBDeployStats(void* db);
-  void LogDBDeployStats();
-#endif  // ROCKSDB_LITE
+  void RecordFlushIOStats();
+  void RecordCompactionIOStats();

  void MaybeScheduleFlushOrCompaction();
  static void BGWorkCompaction(void* db);
@@ -373,6 +390,7 @@ class DBImpl : public DB {
  // Call compaction filter if is_compaction_v2 is not true. Then iterate
  // through input and compact the kv-pairs
  Status ProcessKeyValueCompaction(
+    bool is_snapshot_supported,
    SequenceNumber visible_at_tip,
    SequenceNumber earliest_snapshot,
    SequenceNumber latest_snapshot,
@@ -449,11 +467,20 @@ class DBImpl : public DB {
  // State below is protected by mutex_
  port::Mutex mutex_;
  port::AtomicPointer shutting_down_;
-  port::CondVar bg_cv_;          // Signalled when background work finishes
+  // This condition variable is signaled on these conditions:
+  // * whenever bg_compaction_scheduled_ goes down to 0
+  // * if bg_manual_only_ > 0, whenever a compaction finishes, even if it hasn't
+  // made any progress
+  // * whenever a compaction made any progress
+  // * whenever bg_flush_scheduled_ value decreases (i.e. whenever a flush is
+  // done, even if it didn't make any progress)
+  // * whenever there is an error in background flush or compaction
+  port::CondVar bg_cv_;
  uint64_t logfile_number_;
  unique_ptr<log::Writer> log_;
  bool log_empty_;
  ColumnFamilyHandleImpl* default_cf_handle_;
+  InternalStats* default_cf_internal_stats_;
  unique_ptr<ColumnFamilyMemTablesImpl> column_family_memtables_;
  struct LogFileNumberSize {
    explicit LogFileNumberSize(uint64_t _number)
@@ -468,8 +495,9 @@ class DBImpl : public DB {
  // only used for dynamically adjusting max_total_wal_size. it is a sum of
  // [write_buffer_size * max_write_buffer_number] over all column families
  uint64_t max_total_in_memory_state_;
-
-  std::string host_name_;
+  // If true, we have only one (default) column family. We use this to optimize
+  // some code-paths
+  bool single_column_family_mode_;

  std::unique_ptr<Directory> db_directory_;

@@ -485,7 +513,8 @@ class DBImpl : public DB {

  // Set of table files to protect from deletion because they are
  // part of ongoing compactions.
-  std::set<uint64_t> pending_outputs_;
+  // map from pending file number ID to their path IDs.
+  FileNumToPathIdMap pending_outputs_;

  // At least one compaction or flush job is pending but not yet scheduled
  // because of the max background thread limit.
@@ -502,14 +531,12 @@ class DBImpl : public DB {
  // number of background memtable flush jobs, submitted to the HIGH pool
  int bg_flush_scheduled_;

-  // Has a background stats log thread scheduled?
-  bool bg_logstats_scheduled_;
-
  // Information for a manual compaction
  struct ManualCompaction {
    ColumnFamilyData* cfd;
    int input_level;
    int output_level;
+    uint32_t output_path_id;
    bool done;
    Status status;
    bool in_progress;           // compaction request being processed?
@@ -522,10 +549,6 @@ class DBImpl : public DB {
  // Have we encountered a background error in paranoid mode?
  Status bg_error_;

-  std::unique_ptr<StatsLogger> logger_;
-
-  int64_t volatile last_log_ts;
-
  // shall we disable deletion of obsolete files
  // if 0 the deletion is enabled.
  // if non-zero, files will not be getting deleted
@@ -550,6 +573,7 @@ class DBImpl : public DB {
  bool flush_on_destroy_; // Used when disableWAL is true.

  static const int KEEP_LOG_FILE_NUM = 1000;
+  static const uint64_t kNoTimeOut = std::numeric_limits<uint64_t>::max();
  std::string db_absolute_path_;

  // count of the number of contiguous delaying writes
@@ -587,6 +611,16 @@ class DBImpl : public DB {
  void InstallSuperVersion(ColumnFamilyData* cfd,
                           DeletionState& deletion_state);

+  // Find Super version and reference it. Based on options, it might return
+  // the thread local cached one.
+  inline SuperVersion* GetAndRefSuperVersion(ColumnFamilyData* cfd);
+
+  // Un-reference the super version and return it to thread local cache if
+  // needed. If it is the last reference of the super version. Clean it up
+  // after un-referencing it.
+  inline void ReturnAndCleanupSuperVersion(ColumnFamilyData* cfd,
+                                           SuperVersion* sv);
+
 #ifndef ROCKSDB_LITE
  using DB::GetPropertiesOfAllTables;
  virtual Status GetPropertiesOfAllTables(ColumnFamilyHandle* column_family,
@@ -599,6 +633,10 @@ class DBImpl : public DB {
  Status GetImpl(const ReadOptions& options, ColumnFamilyHandle* column_family,
                 const Slice& key, std::string* value,
                 bool* value_found = nullptr);
+
+  bool GetIntPropertyInternal(ColumnFamilyHandle* column_family,
+                              DBPropertyType property_type,
+                              bool need_out_of_mutex, uint64_t* value);
 };

 // Sanitize db options.  The caller should delete result.info_log if
@@ -609,15 +647,11 @@ extern Options SanitizeOptions(const std::string& db,
                               const Options& src);
 extern DBOptions SanitizeOptions(const std::string& db, const DBOptions& src);

-// Determine compression type, based on user options, level of the output
-// file and whether compression is disabled.
-// If enable_compression is false, then compression is always disabled no
-// matter what the values of the other two parameters are.
-// Otherwise, the compression type is determined based on options and level.
-CompressionType GetCompressionType(const Options& options, int level,
-                                   const bool enable_compression);
-
-// Determine compression type for L0 file written by memtable flush.
-CompressionType GetCompressionFlush(const Options& options);
+// Fix user-supplied options to be reasonable
+template <class T, class V>
+static void ClipToRange(T* ptr, V minvalue, V maxvalue) {
+  if (static_cast<V>(*ptr) > maxvalue) *ptr = maxvalue;
+  if (static_cast<V>(*ptr) < minvalue) *ptr = minvalue;
+}

 }  // namespace rocksdb
@@ -81,10 +81,11 @@ Status DBImpl::TEST_CompactRange(int level, const Slice* begin,
    cfd = cfh->cfd();
  }
  int output_level =
-      (cfd->options()->compaction_style == kCompactionStyleUniversal)
+      (cfd->options()->compaction_style == kCompactionStyleUniversal ||
+       cfd->options()->compaction_style == kCompactionStyleFIFO)
          ? level
          : level + 1;
-  return RunManualCompaction(cfd, level, output_level, begin, end);
+  return RunManualCompaction(cfd, level, output_level, 0, begin, end);
 }

 Status DBImpl::TEST_FlushMemTable(bool wait) {
@@ -65,9 +65,7 @@ Status DBImplReadOnly::Get(const ReadOptions& options,
  if (super_version->mem->Get(lkey, value, &s, merge_context,
                              *cfd->options())) {
  } else {
-    Version::GetStats stats;
-    super_version->current->Get(options, lkey, value, &s, &merge_context,
-                                &stats);
+    super_version->current->Get(options, lkey, value, &s, &merge_context);
  }
  return s;
 }
@@ -78,12 +76,42 @@ Iterator* DBImplReadOnly::NewIterator(const ReadOptions& options,
  auto cfd = cfh->cfd();
  SuperVersion* super_version = cfd->GetSuperVersion()->Ref();
  SequenceNumber latest_snapshot = versions_->LastSequence();
-  Iterator* internal_iter = NewInternalIterator(options, cfd, super_version);
-  return NewDBIterator(
-      env_, *cfd->options(), cfd->user_comparator(), internal_iter,
+  auto db_iter = NewArenaWrappedDbIterator(
+      env_, *cfd->options(), cfd->user_comparator(),
      (options.snapshot != nullptr
           ? reinterpret_cast<const SnapshotImpl*>(options.snapshot)->number_
           : latest_snapshot));
+  auto internal_iter =
+      NewInternalIterator(options, cfd, super_version, db_iter->GetArena());
+  db_iter->SetIterUnderDBIter(internal_iter);
+  return db_iter;
+}
+
+Status DBImplReadOnly::NewIterators(
+    const ReadOptions& options,
+    const std::vector<ColumnFamilyHandle*>& column_families,
+    std::vector<Iterator*>* iterators) {
+  if (iterators == nullptr) {
+    return Status::InvalidArgument("iterators not allowed to be nullptr");
+  }
+  iterators->clear();
+  iterators->reserve(column_families.size());
+  SequenceNumber latest_snapshot = versions_->LastSequence();
+
+  for (auto cfh : column_families) {
+    auto cfd = reinterpret_cast<ColumnFamilyHandleImpl*>(cfh)->cfd();
+    auto db_iter = NewArenaWrappedDbIterator(
+        env_, *cfd->options(), cfd->user_comparator(),
+        options.snapshot != nullptr
+            ? reinterpret_cast<const SnapshotImpl*>(options.snapshot)->number_
+            : latest_snapshot);
+    auto internal_iter = NewInternalIterator(
+        options, cfd, cfd->GetSuperVersion()->Ref(), db_iter->GetArena());
+    db_iter->SetIterUnderDBIter(internal_iter);
+    iterators->push_back(db_iter);
+  }
+
+  return Status::OK();
 }

 Status DB::OpenForReadOnly(const Options& options, const std::string& dbname,
@@ -20,7 +20,6 @@
 #include "rocksdb/db.h"
 #include "rocksdb/env.h"
 #include "port/port.h"
-#include "util/stats_logger.h"

 namespace rocksdb {

@@ -33,63 +32,62 @@ class DBImplReadOnly : public DBImpl {
  using DB::Get;
  virtual Status Get(const ReadOptions& options,
                     ColumnFamilyHandle* column_family, const Slice& key,
-                     std::string* value);
+                     std::string* value) override;

  // TODO: Implement ReadOnly MultiGet?

  using DBImpl::NewIterator;
  virtual Iterator* NewIterator(const ReadOptions&,
-                                ColumnFamilyHandle* column_family);
+                                ColumnFamilyHandle* column_family) override;

  virtual Status NewIterators(
      const ReadOptions& options,
-      const std::vector<ColumnFamilyHandle*>& column_family,
-      std::vector<Iterator*>* iterators) {
-   // TODO
-    return Status::NotSupported("Not supported yet.");
-  }
+      const std::vector<ColumnFamilyHandle*>& column_families,
+      std::vector<Iterator*>* iterators) override;

  using DBImpl::Put;
  virtual Status Put(const WriteOptions& options,
                     ColumnFamilyHandle* column_family, const Slice& key,
-                     const Slice& value) {
+                     const Slice& value) override {
    return Status::NotSupported("Not supported operation in read only mode.");
  }
  using DBImpl::Merge;
  virtual Status Merge(const WriteOptions& options,
                       ColumnFamilyHandle* column_family, const Slice& key,
-                       const Slice& value) {
+                       const Slice& value) override {
    return Status::NotSupported("Not supported operation in read only mode.");
  }
  using DBImpl::Delete;
  virtual Status Delete(const WriteOptions& options,
-                        ColumnFamilyHandle* column_family, const Slice& key) {
+                        ColumnFamilyHandle* column_family,
+                        const Slice& key) override {
    return Status::NotSupported("Not supported operation in read only mode.");
  }
-  virtual Status Write(const WriteOptions& options, WriteBatch* updates) {
+  virtual Status Write(const WriteOptions& options,
+                       WriteBatch* updates) override {
    return Status::NotSupported("Not supported operation in read only mode.");
  }
  using DBImpl::CompactRange;
  virtual Status CompactRange(ColumnFamilyHandle* column_family,
                              const Slice* begin, const Slice* end,
-                              bool reduce_level = false,
-                              int target_level = -1) {
+                              bool reduce_level = false, int target_level = -1,
+                              uint32_t target_path_id = 0) override {
    return Status::NotSupported("Not supported operation in read only mode.");
  }
-  virtual Status DisableFileDeletions() {
+  virtual Status DisableFileDeletions() override {
    return Status::NotSupported("Not supported operation in read only mode.");
  }
-  virtual Status EnableFileDeletions(bool force) {
+  virtual Status EnableFileDeletions(bool force) override {
    return Status::NotSupported("Not supported operation in read only mode.");
  }
  virtual Status GetLiveFiles(std::vector<std::string>&,
                              uint64_t* manifest_file_size,
-                              bool flush_memtable = true) {
+                              bool flush_memtable = true) override {
    return Status::NotSupported("Not supported operation in read only mode.");
  }
  using DBImpl::Flush;
  virtual Status Flush(const FlushOptions& options,
-                       ColumnFamilyHandle* column_family) {
+                       ColumnFamilyHandle* column_family) override {
    return Status::NotSupported("Not supported operation in read only mode.");
  }

@@ -10,6 +10,8 @@
 #include "db/db_iter.h"
 #include <stdexcept>
 #include <deque>
+#include <string>
+#include <limits>

 #include "db/filename.h"
 #include "db/dbformat.h"
@@ -18,6 +20,7 @@
 #include "rocksdb/iterator.h"
 #include "rocksdb/merge_operator.h"
 #include "port/port.h"
+#include "util/arena.h"
 #include "util/logging.h"
 #include "util/mutexlock.h"
 #include "util/perf_context_imp.h"
@@ -37,8 +40,6 @@ static void DumpInternalIter(Iterator* iter) {
 }
 #endif

-namespace {
-
 // Memtables and sstables that make the DB representation contain
 // (userkey,seq,type) => uservalue entries.  DBIter
 // combines multiple entries for the same userkey found in the DB
@@ -57,9 +58,10 @@ class DBIter: public Iterator {
    kReverse
  };

-  DBIter(Env* env, const Options& options,
-         const Comparator* cmp, Iterator* iter, SequenceNumber s)
-      : env_(env),
+  DBIter(Env* env, const Options& options, const Comparator* cmp,
+         Iterator* iter, SequenceNumber s, bool arena_mode)
+      : arena_mode_(arena_mode),
+        env_(env),
        logger_(options.info_log.get()),
        user_comparator_(cmp),
        user_merge_operator_(options.merge_operator.get()),
@@ -69,12 +71,21 @@ class DBIter: public Iterator {
        valid_(false),
        current_entry_is_merged_(false),
        statistics_(options.statistics.get()) {
-    RecordTick(statistics_, NO_ITERATORS, 1);
+    RecordTick(statistics_, NO_ITERATORS);
+    has_prefix_extractor_ = (options.prefix_extractor.get() != nullptr);
    max_skip_ = options.max_sequential_skip_in_iterations;
  }
  virtual ~DBIter() {
    RecordTick(statistics_, NO_ITERATORS, -1);
-    delete iter_;
+    if (!arena_mode_) {
+      delete iter_;
+    } else {
+      iter_->~Iterator();
+    }
+  }
+  virtual void SetIter(Iterator* iter) {
+    assert(iter_ == nullptr);
+    iter_ = iter;
  }
  virtual bool Valid() const { return valid_; }
  virtual Slice key() const {
@@ -101,9 +112,14 @@ class DBIter: public Iterator {
  virtual void SeekToLast();

 private:
+  void PrevInternal();
+  void FindParseableKey(ParsedInternalKey* ikey, Direction direction);
+  bool FindValueForCurrentKey();
+  bool FindValueForCurrentKeyUsingSeek();
+  void FindPrevUserKey();
+  void FindNextUserKey();
  inline void FindNextUserEntry(bool skipping);
  void FindNextUserEntryInternal(bool skipping);
-  void FindPrevUserEntry();
  bool ParseKey(ParsedInternalKey* key);
  void MergeValuesNewToOld();

@@ -116,17 +132,18 @@ class DBIter: public Iterator {
    }
  }

+  bool has_prefix_extractor_;
+  bool arena_mode_;
  Env* const env_;
  Logger* logger_;
  const Comparator* const user_comparator_;
  const MergeOperator* const user_merge_operator_;
-  Iterator* const iter_;
+  Iterator* iter_;
  SequenceNumber const sequence_;

  Status status_;
-  IterKey saved_key_;   // == current key when direction_==kReverse
-  std::string saved_value_;   // == current raw value when direction_==kReverse
-  std::string skip_key_;
+  IterKey saved_key_;
+  std::string saved_value_;
  Direction direction_;
  bool valid_;
  bool current_entry_is_merged_;
@@ -152,20 +169,11 @@ inline bool DBIter::ParseKey(ParsedInternalKey* ikey) {
 void DBIter::Next() {
  assert(valid_);

-  if (direction_ == kReverse) {  // Switch directions?
+  if (direction_ == kReverse) {
+    FindNextUserKey();
    direction_ = kForward;
-    // iter_ is pointing just before the entries for this->key(),
-    // so advance into the range of entries for this->key() and then
-    // use the normal skipping code below.
    if (!iter_->Valid()) {
      iter_->SeekToFirst();
-    } else {
-      iter_->Next();
-    }
-    if (!iter_->Valid()) {
-      valid_ = false;
-      saved_key_.Clear();
-      return;
    }
  }

@@ -177,7 +185,6 @@ void DBIter::Next() {
  FindNextUserEntry(true /* skipping the current user key */);
 }

-
 // PRE: saved_key_ has the current user key if skipping
 // POST: saved_key_ should have the next user key if valid_,
 //       if the current entry is a result of merge
@@ -212,18 +219,18 @@ void DBIter::FindNextUserEntryInternal(bool skipping) {
          case kTypeDeletion:
            // Arrange to skip all upcoming entries for this key since
            // they are hidden by this deletion.
-            saved_key_.SetUserKey(ikey.user_key);
+            saved_key_.SetKey(ikey.user_key);
            skipping = true;
            num_skipped = 0;
            PERF_COUNTER_ADD(internal_delete_skipped_count, 1);
            break;
          case kTypeValue:
            valid_ = true;
-            saved_key_.SetUserKey(ikey.user_key);
+            saved_key_.SetKey(ikey.user_key);
            return;
          case kTypeMerge:
            // By now, we are sure the current ikey is going to yield a value
-            saved_key_.SetUserKey(ikey.user_key);
+            saved_key_.SetKey(ikey.user_key);
            current_entry_is_merged_ = true;
            valid_ = true;
            MergeValuesNewToOld();  // Go to a different state machine
@@ -319,100 +326,228 @@ void DBIter::MergeValuesNewToOld() {

 void DBIter::Prev() {
  assert(valid_);
-
-  // Throw an exception now if merge_operator is provided
-  // TODO: support backward iteration
-  if (user_merge_operator_) {
-    Log(logger_, "Prev not supported yet if merge_operator is provided");
-    throw std::logic_error("DBIter::Prev backward iteration not supported"
-                           " if merge_operator is provided");
-  }
-
-  if (direction_ == kForward) {  // Switch directions?
-    // iter_ is pointing at the current entry.  Scan backwards until
-    // the key changes so we can use the normal reverse scanning code.
-    assert(iter_->Valid());  // Otherwise valid_ would have been false
-    saved_key_.SetUserKey(ExtractUserKey(iter_->key()));
-    while (true) {
-      iter_->Prev();
-      if (!iter_->Valid()) {
-        valid_ = false;
-        saved_key_.Clear();
-        ClearSavedValue();
-        return;
-      }
-      if (user_comparator_->Compare(ExtractUserKey(iter_->key()),
-                                    saved_key_.GetKey()) < 0) {
-        break;
-      }
-    }
+  if (direction_ == kForward) {
+    FindPrevUserKey();
    direction_ = kReverse;
  }
-
-  FindPrevUserEntry();
+  PrevInternal();
 }

-void DBIter::FindPrevUserEntry() {
-  assert(direction_ == kReverse);
-  uint64_t num_skipped = 0;
-
-  ValueType value_type = kTypeDeletion;
-  bool saved_key_valid = true;
-  if (iter_->Valid()) {
-    do {
-      ParsedInternalKey ikey;
-      if (ParseKey(&ikey) && ikey.sequence <= sequence_) {
-        if ((value_type != kTypeDeletion) &&
-            user_comparator_->Compare(ikey.user_key, saved_key_.GetKey()) < 0) {
-          // We encountered a non-deleted value in entries for previous keys,
-          break;
-        }
-        value_type = ikey.type;
-        if (value_type == kTypeDeletion) {
-          saved_key_.Clear();
-          ClearSavedValue();
-          saved_key_valid = false;
-        } else {
-          Slice raw_value = iter_->value();
-          if (saved_value_.capacity() > raw_value.size() + 1048576) {
-            std::string empty;
-            swap(empty, saved_value_);
-          }
-          saved_key_.SetUserKey(ExtractUserKey(iter_->key()));
-          saved_value_.assign(raw_value.data(), raw_value.size());
-        }
-      } else {
-        // In the case of ikey.sequence > sequence_, we might have already
-        // iterated to a different user key.
-        saved_key_valid = false;
-      }
-      num_skipped++;
-      // If we have sequentially iterated via numerous keys and still not
-      // found the prev user-key, then it is better to seek so that we can
-      // avoid too many key comparisons. We seek to the first occurence of
-      // our current key by looking for max sequence number.
-      if (saved_key_valid && num_skipped > max_skip_) {
-        num_skipped = 0;
-        std::string last_key;
-        AppendInternalKey(&last_key, ParsedInternalKey(saved_key_.GetKey(),
-                                                       kMaxSequenceNumber,
-                                                       kValueTypeForSeek));
-        iter_->Seek(last_key);
-        RecordTick(statistics_, NUMBER_OF_RESEEKS_IN_ITERATION);
-      } else {
-        iter_->Prev();
-      }
-    } while (iter_->Valid());
+void DBIter::PrevInternal() {
+  if (!iter_->Valid()) {
+    valid_ = false;
+    return;
  }

-  if (value_type == kTypeDeletion) {
-    // End
+  ParsedInternalKey ikey;
+
+  while (iter_->Valid()) {
+    saved_key_.SetKey(ExtractUserKey(iter_->key()));
+    if (FindValueForCurrentKey()) {
+      valid_ = true;
+      if (!iter_->Valid()) {
+        return;
+      }
+      FindParseableKey(&ikey, kReverse);
+      if (user_comparator_->Compare(ikey.user_key, saved_key_.GetKey()) == 0) {
+        FindPrevUserKey();
+      }
+      return;
+    }
+    if (!iter_->Valid()) {
+      break;
+    }
+    FindParseableKey(&ikey, kReverse);
+    if (user_comparator_->Compare(ikey.user_key, saved_key_.GetKey()) == 0) {
+
+      FindPrevUserKey();
+    }
+  }
+  // We haven't found any key - iterator is not valid
+  assert(!iter_->Valid());
+  valid_ = false;
+}
+
+// This function checks, if the entry with biggest sequence_number <= sequence_
+// is non kTypeDeletion. If it's not, we save value in saved_value_
+bool DBIter::FindValueForCurrentKey() {
+  assert(iter_->Valid());
+  // Contains operands for merge operator.
+  std::deque<std::string> operands;
+  // last entry before merge (could be kTypeDeletion or kTypeValue)
+  ValueType last_not_merge_type = kTypeDeletion;
+  ValueType last_key_entry_type = kTypeDeletion;
+
+  ParsedInternalKey ikey;
+  FindParseableKey(&ikey, kReverse);
+
+  size_t num_skipped = 0;
+  while (iter_->Valid() && ikey.sequence <= sequence_ &&
+         (user_comparator_->Compare(ikey.user_key, saved_key_.GetKey()) == 0)) {
+    // We iterate too much: let's use Seek() to avoid too much key comparisons
+    if (num_skipped >= max_skip_) {
+      return FindValueForCurrentKeyUsingSeek();
+    }
+
+    last_key_entry_type = ikey.type;
+    switch (last_key_entry_type) {
+      case kTypeValue:
+        operands.clear();
+        saved_value_ = iter_->value().ToString();
+        last_not_merge_type = kTypeValue;
+        break;
+      case kTypeDeletion:
+        operands.clear();
+        last_not_merge_type = kTypeDeletion;
+        break;
+      case kTypeMerge:
+        assert(user_merge_operator_ != nullptr);
+        operands.push_back(iter_->value().ToString());
+        break;
+      default:
+        assert(false);
+    }
+
+    assert(user_comparator_->Compare(ikey.user_key, saved_key_.GetKey()) == 0);
+    iter_->Prev();
+    ++num_skipped;
+    FindParseableKey(&ikey, kReverse);
+  }
+
+  switch (last_key_entry_type) {
+    case kTypeDeletion:
+      valid_ = false;
+      return false;
+    case kTypeMerge:
+      if (last_not_merge_type == kTypeDeletion) {
+        user_merge_operator_->FullMerge(saved_key_.GetKey(), nullptr, operands,
+                                        &saved_value_, logger_);
+      } else {
+        assert(last_not_merge_type == kTypeValue);
+        std::string last_put_value = saved_value_;
+        Slice temp_slice(last_put_value);
+        user_merge_operator_->FullMerge(saved_key_.GetKey(), &temp_slice,
+                                        operands, &saved_value_, logger_);
+      }
+      break;
+    case kTypeValue:
+      // do nothing - we've already has value in saved_value_
+      break;
+    default:
+      assert(false);
+      break;
+  }
+  valid_ = true;
+  return true;
+}
+
+// This function is used in FindValueForCurrentKey.
+// We use Seek() function instead of Prev() to find necessary value
+bool DBIter::FindValueForCurrentKeyUsingSeek() {
+  std::string last_key;
+  AppendInternalKey(&last_key, ParsedInternalKey(saved_key_.GetKey(), sequence_,
+                                                 kValueTypeForSeek));
+  iter_->Seek(last_key);
+  RecordTick(statistics_, NUMBER_OF_RESEEKS_IN_ITERATION);
+
+  // assume there is at least one parseable key for this user key
+  ParsedInternalKey ikey;
+  FindParseableKey(&ikey, kForward);
+
+  if (ikey.type == kTypeValue || ikey.type == kTypeDeletion) {
+    if (ikey.type == kTypeValue) {
+      saved_value_ = iter_->value().ToString();
+      valid_ = true;
+      return true;
+    }
    valid_ = false;
-    saved_key_.Clear();
-    ClearSavedValue();
-    direction_ = kForward;
-  } else {
+    return false;
+  }
+
+  // kTypeMerge. We need to collect all kTypeMerge values and save them
+  // in operands
+  std::deque<std::string> operands;
+  while (iter_->Valid() &&
+         (user_comparator_->Compare(ikey.user_key, saved_key_.GetKey()) == 0) &&
+         ikey.type == kTypeMerge) {
+    operands.push_front(iter_->value().ToString());
+    iter_->Next();
+    FindParseableKey(&ikey, kForward);
+  }
+
+  if (!iter_->Valid() ||
+      (user_comparator_->Compare(ikey.user_key, saved_key_.GetKey()) != 0) ||
+      ikey.type == kTypeDeletion) {
+    user_merge_operator_->FullMerge(saved_key_.GetKey(), nullptr, operands,
+                                    &saved_value_, logger_);
+
+    // Make iter_ valid and point to saved_key_
+    if (!iter_->Valid() ||
+        (user_comparator_->Compare(ikey.user_key, saved_key_.GetKey()) != 0)) {
+      iter_->Seek(last_key);
+      RecordTick(statistics_, NUMBER_OF_RESEEKS_IN_ITERATION);
+    }
    valid_ = true;
+    return true;
+  }
+
+  const Slice& value = iter_->value();
+  user_merge_operator_->FullMerge(saved_key_.GetKey(), &value, operands,
+                                  &saved_value_, logger_);
+  valid_ = true;
+  return true;
+}
+
+// Used in Next to change directions
+// Go to next user key
+// Don't use Seek(),
+// because next user key will be very close
+void DBIter::FindNextUserKey() {
+  if (!iter_->Valid()) {
+    return;
+  }
+  ParsedInternalKey ikey;
+  FindParseableKey(&ikey, kForward);
+  while (iter_->Valid() &&
+         user_comparator_->Compare(ikey.user_key, saved_key_.GetKey()) != 0) {
+    iter_->Next();
+    FindParseableKey(&ikey, kForward);
+  }
+}
+
+// Go to previous user_key
+void DBIter::FindPrevUserKey() {
+  if (!iter_->Valid()) {
+    return;
+  }
+  size_t num_skipped = 0;
+  ParsedInternalKey ikey;
+  FindParseableKey(&ikey, kReverse);
+  while (iter_->Valid() &&
+         user_comparator_->Compare(ikey.user_key, saved_key_.GetKey()) == 0) {
+    if (num_skipped >= max_skip_) {
+      num_skipped = 0;
+      IterKey last_key;
+      last_key.SetInternalKey(ParsedInternalKey(
+          saved_key_.GetKey(), kMaxSequenceNumber, kValueTypeForSeek));
+      iter_->Seek(last_key.GetKey());
+      RecordTick(statistics_, NUMBER_OF_RESEEKS_IN_ITERATION);
+    }
+
+    iter_->Prev();
+    ++num_skipped;
+    FindParseableKey(&ikey, kReverse);
+  }
+}
+
+// Skip all unparseable keys
+void DBIter::FindParseableKey(ParsedInternalKey* ikey, Direction direction) {
+  while (iter_->Valid() && !ParseKey(ikey)) {
+    if (direction == kReverse) {
+      iter_->Prev();
+    } else {
+      iter_->Next();
+    }
  }
 }

@@ -433,6 +568,11 @@ void DBIter::Seek(const Slice& target) {
 }

 void DBIter::SeekToFirst() {
+  // Don't use iter_::Seek() if we set a prefix extractor
+  // because prefix seek wiil be used.
+  if (has_prefix_extractor_) {
+    max_skip_ = std::numeric_limits<uint64_t>::max();
+  }
  direction_ = kForward;
  ClearSavedValue();
  PERF_TIMER_AUTO(seek_internal_seek_time);
@@ -446,32 +586,62 @@ void DBIter::SeekToFirst() {
 }

 void DBIter::SeekToLast() {
-  // Throw an exception for now if merge_operator is provided
-  // TODO: support backward iteration
-  if (user_merge_operator_) {
-    Log(logger_, "SeekToLast not supported yet if merge_operator is provided");
-    throw std::logic_error("DBIter::SeekToLast: backward iteration not"
-                           " supported if merge_operator is provided");
+  // Don't use iter_::Seek() if we set a prefix extractor
+  // because prefix seek wiil be used.
+  if (has_prefix_extractor_) {
+    max_skip_ = std::numeric_limits<uint64_t>::max();
  }
-
  direction_ = kReverse;
  ClearSavedValue();
  PERF_TIMER_AUTO(seek_internal_seek_time);
  iter_->SeekToLast();
  PERF_TIMER_STOP(seek_internal_seek_time);
-  FindPrevUserEntry();
+
+  PrevInternal();
 }

-}  // anonymous namespace
+Iterator* NewDBIterator(Env* env, const Options& options,
+                        const Comparator* user_key_comparator,
+                        Iterator* internal_iter,
+                        const SequenceNumber& sequence) {
+  return new DBIter(env, options, user_key_comparator, internal_iter, sequence,
+                    false);
+}

-Iterator* NewDBIterator(
-    Env* env,
-    const Options& options,
-    const Comparator *user_key_comparator,
-    Iterator* internal_iter,
+ArenaWrappedDBIter::~ArenaWrappedDBIter() { db_iter_->~DBIter(); }
+
+void ArenaWrappedDBIter::SetDBIter(DBIter* iter) { db_iter_ = iter; }
+
+void ArenaWrappedDBIter::SetIterUnderDBIter(Iterator* iter) {
+  static_cast<DBIter*>(db_iter_)->SetIter(iter);
+}
+
+inline bool ArenaWrappedDBIter::Valid() const { return db_iter_->Valid(); }
+inline void ArenaWrappedDBIter::SeekToFirst() { db_iter_->SeekToFirst(); }
+inline void ArenaWrappedDBIter::SeekToLast() { db_iter_->SeekToLast(); }
+inline void ArenaWrappedDBIter::Seek(const Slice& target) {
+  db_iter_->Seek(target);
+}
+inline void ArenaWrappedDBIter::Next() { db_iter_->Next(); }
+inline void ArenaWrappedDBIter::Prev() { db_iter_->Prev(); }
+inline Slice ArenaWrappedDBIter::key() const { return db_iter_->key(); }
+inline Slice ArenaWrappedDBIter::value() const { return db_iter_->value(); }
+inline Status ArenaWrappedDBIter::status() const { return db_iter_->status(); }
+void ArenaWrappedDBIter::RegisterCleanup(CleanupFunction function, void* arg1,
+                                         void* arg2) {
+  db_iter_->RegisterCleanup(function, arg1, arg2);
+}
+
+ArenaWrappedDBIter* NewArenaWrappedDbIterator(
+    Env* env, const Options& options, const Comparator* user_key_comparator,
    const SequenceNumber& sequence) {
-  return new DBIter(env, options, user_key_comparator,
-                    internal_iter, sequence);
+  ArenaWrappedDBIter* iter = new ArenaWrappedDBIter();
+  Arena* arena = iter->GetArena();
+  auto mem = arena->AllocateAligned(sizeof(DBIter));
+  DBIter* db_iter = new (mem)
+      DBIter(env, options, user_key_comparator, nullptr, sequence, true);
+  iter->SetDBIter(db_iter);
+  return iter;
 }

 }  // namespace rocksdb
@@ -11,9 +11,14 @@
 #include <stdint.h>
 #include "rocksdb/db.h"
 #include "db/dbformat.h"
+#include "util/arena.h"
+#include "util/autovector.h"

 namespace rocksdb {

+class Arena;
+class DBIter;
+
 // Return a new iterator that converts internal keys (yielded by
 // "*internal_iter") that were live at the specified "sequence" number
 // into appropriate user keys.
@@ -24,4 +29,45 @@ extern Iterator* NewDBIterator(
    Iterator* internal_iter,
    const SequenceNumber& sequence);

+// A wrapper iterator which wraps DB Iterator and the arena, with which the DB
+// iterator is supposed be allocated. This class is used as an entry point of
+// a iterator hierarchy whose memory can be allocated inline. In that way,
+// accessing the iterator tree can be more cache friendly. It is also faster
+// to allocate.
+class ArenaWrappedDBIter : public Iterator {
+ public:
+  virtual ~ArenaWrappedDBIter();
+
+  // Get the arena to be used to allocate memory for DBIter to be wrapped,
+  // as well as child iterators in it.
+  virtual Arena* GetArena() { return &arena_; }
+
+  // Set the DB Iterator to be wrapped
+
+  virtual void SetDBIter(DBIter* iter);
+
+  // Set the internal iterator wrapped inside the DB Iterator. Usually it is
+  // a merging iterator.
+  virtual void SetIterUnderDBIter(Iterator* iter);
+  virtual bool Valid() const override;
+  virtual void SeekToFirst() override;
+  virtual void SeekToLast() override;
+  virtual void Seek(const Slice& target) override;
+  virtual void Next() override;
+  virtual void Prev() override;
+  virtual Slice key() const override;
+  virtual Slice value() const override;
+  virtual Status status() const override;
+  void RegisterCleanup(CleanupFunction function, void* arg1, void* arg2);
+
+ private:
+  DBIter* db_iter_;
+  Arena arena_;
+};
+
+// Generate the arena wrapped iterator class.
+extern ArenaWrappedDBIter* NewArenaWrappedDbIterator(
+    Env* env, const Options& options, const Comparator* user_key_comparator,
+    const SequenceNumber& sequence);
+
 }  // namespace rocksdb
@@ -1,95 +0,0 @@
-//  Copyright (c) 2013, Facebook, Inc.  All rights reserved.
-//  This source code is licensed under the BSD-style license found in the
-//  LICENSE file in the root directory of this source tree. An additional grant
-//  of patent rights can be found in the PATENTS file in the same directory.
-//
-// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file. See the AUTHORS file for names of contributors.
-
-#include "db/db_impl.h"
-#include <string>
-#include <stdint.h>
-#include <stdio.h>
-#include "db/version_set.h"
-#include "rocksdb/db.h"
-#include "rocksdb/env.h"
-#include "port/port.h"
-#include "util/mutexlock.h"
-
-namespace rocksdb {
-
-void DBImpl::MaybeScheduleLogDBDeployStats() {
-// we did say maybe
-#ifndef ROCKSDB_LITE
-  // There is a lock in the actual logger.
-  if (!logger_ || options_.db_stats_log_interval < 0
-      || host_name_.empty()) {
-    return;
-  }
-
-  if(bg_logstats_scheduled_ || shutting_down_.Acquire_Load()) {
-    // Already scheduled
-  } else {
-    int64_t current_ts = 0;
-    Status st = env_->GetCurrentTime(&current_ts);
-    if (!st.ok()) {
-      return;
-    }
-    if ((current_ts - last_log_ts) < options_.db_stats_log_interval) {
-      return;
-    }
-    last_log_ts = current_ts;
-    bg_logstats_scheduled_ = true;
-    env_->Schedule(&DBImpl::BGLogDBDeployStats, this);
-  }
-}
-
-void DBImpl::BGLogDBDeployStats(void* db) {
-  DBImpl* db_inst = reinterpret_cast<DBImpl*>(db);
-  db_inst->LogDBDeployStats();
-}
-
-void DBImpl::LogDBDeployStats() {
-  mutex_.Lock();
-
-  if (shutting_down_.Acquire_Load()) {
-    bg_logstats_scheduled_ = false;
-    bg_cv_.SignalAll();
-    mutex_.Unlock();
-    return;
-  }
-
-  char tmp_ver[100];
-  sprintf(tmp_ver, "%d.%d", kMajorVersion, kMinorVersion);
-  std::string version_info(tmp_ver);
-
-  uint64_t file_total_size = 0;
-  uint32_t file_total_num = 0;
-  Version* current = default_cf_handle_->cfd()->current();
-  for (int i = 0; i < current->NumberLevels(); i++) {
-    file_total_num += current->NumLevelFiles(i);
-    file_total_size += current->NumLevelBytes(i);
-  }
-
-  Version::LevelSummaryStorage scratch;
-  const char* file_num_summary = current->LevelSummary(&scratch);
-  std::string file_num_per_level(file_num_summary);
-  std::string data_size_per_level(file_num_summary);
-
-  mutex_.Unlock();
-
-  int64_t unix_ts;
-  env_->GetCurrentTime(&unix_ts);
-
-  logger_->Log_Deploy_Stats(version_info, host_name_,
-      db_absolute_path_, file_total_size, file_total_num, file_num_per_level,
-      data_size_per_level, unix_ts);
-
-  mutex_.Lock();
-  bg_logstats_scheduled_ = false;
-  bg_cv_.SignalAll();
-  mutex_.Unlock();
-#endif
-}
-}
@@ -9,6 +9,7 @@

 #pragma once
 #include <stdio.h>
+#include <string>
 #include "rocksdb/comparator.h"
 #include "rocksdb/db.h"
 #include "rocksdb/filter_policy.h"
@@ -146,6 +147,11 @@ class InternalKey {
    AppendInternalKey(&rep_, ParsedInternalKey(user_key, s, t));
  }

+  bool Valid() const {
+    ParsedInternalKey parsed;
+    return ParseInternalKey(Slice(rep_), &parsed);
+  }
+
  void DecodeFrom(const Slice& s) { rep_.assign(s.data(), s.size()); }
  Slice Encode() const {
    assert(!rep_.empty());
@@ -249,26 +255,84 @@ class IterKey {

  Slice GetKey() const { return Slice(key_, key_size_); }

+  const size_t Size() { return key_size_; }
+
  void Clear() { key_size_ = 0; }

-  void SetUserKey(const Slice& user_key) {
-    size_t size = user_key.size();
+  // Append "non_shared_data" to its back, from "shared_len"
+  // This function is used in Block::Iter::ParseNextKey
+  // shared_len: bytes in [0, shard_len-1] would be remained
+  // non_shared_data: data to be append, its length must be >= non_shared_len
+  void TrimAppend(const size_t shared_len, const char* non_shared_data,
+                  const size_t non_shared_len) {
+    assert(shared_len <= key_size_);
+
+    size_t total_size = shared_len + non_shared_len;
+    if (total_size <= buf_size_) {
+      key_size_ = total_size;
+    } else {
+      // Need to allocate space, delete previous space
+      char* p = new char[total_size];
+      memcpy(p, key_, shared_len);
+
+      if (key_ != nullptr && key_ != space_) {
+        delete[] key_;
+      }
+
+      key_ = p;
+      key_size_ = total_size;
+      buf_size_ = total_size;
+    }
+
+    memcpy(key_ + shared_len, non_shared_data, non_shared_len);
+  }
+
+  void SetKey(const Slice& key) {
+    size_t size = key.size();
    EnlargeBufferIfNeeded(size);
-    memcpy(key_, user_key.data(), size);
+    memcpy(key_, key.data(), size);
    key_size_ = size;
  }

+  void SetInternalKey(const Slice& key_prefix, const Slice& user_key,
+                      SequenceNumber s,
+                      ValueType value_type = kValueTypeForSeek) {
+    size_t psize = key_prefix.size();
+    size_t usize = user_key.size();
+    EnlargeBufferIfNeeded(psize + usize + sizeof(uint64_t));
+    if (psize > 0) {
+      memcpy(key_, key_prefix.data(), psize);
+    }
+    memcpy(key_ + psize, user_key.data(), usize);
+    EncodeFixed64(key_ + usize + psize, PackSequenceAndType(s, value_type));
+    key_size_ = psize + usize + sizeof(uint64_t);
+  }
+
  void SetInternalKey(const Slice& user_key, SequenceNumber s,
                      ValueType value_type = kValueTypeForSeek) {
-    size_t usize = user_key.size();
-    EnlargeBufferIfNeeded(usize + sizeof(uint64_t));
-    memcpy(key_, user_key.data(), usize);
-    EncodeFixed64(key_ + usize, PackSequenceAndType(s, value_type));
-    key_size_ = usize + sizeof(uint64_t);
+    SetInternalKey(Slice(), user_key, s, value_type);
+  }
+
+  void Reserve(size_t size) {
+    EnlargeBufferIfNeeded(size);
+    key_size_ = size;
  }

  void SetInternalKey(const ParsedInternalKey& parsed_key) {
-    SetInternalKey(parsed_key.user_key, parsed_key.sequence, parsed_key.type);
+    SetInternalKey(Slice(), parsed_key);
+  }
+
+  void SetInternalKey(const Slice& key_prefix,
+                      const ParsedInternalKey& parsed_key_suffix) {
+    SetInternalKey(key_prefix, parsed_key_suffix.user_key,
+                   parsed_key_suffix.sequence, parsed_key_suffix.type);
+  }
+
+  void EncodeLengthPrefixedKey(const Slice& key) {
+    auto size = key.size();
+    EnlargeBufferIfNeeded(size + VarintLength(size));
+    char* ptr = EncodeVarint32(key_, size);
+    memcpy(ptr, key.data(), size);
  }

 private:
@@ -110,6 +110,45 @@ TEST(FormatTest, InternalKeyShortestSuccessor) {
            ShortSuccessor(IKey("\xff\xff", 100, kTypeValue)));
 }

+TEST(FormatTest, IterKeyOperation) {
+  IterKey k;
+  const char p[] = "abcdefghijklmnopqrstuvwxyz";
+  const char q[] = "0123456789";
+
+  ASSERT_EQ(std::string(k.GetKey().data(), k.GetKey().size()),
+            std::string(""));
+
+  k.TrimAppend(0, p, 3);
+  ASSERT_EQ(std::string(k.GetKey().data(), k.GetKey().size()),
+            std::string("abc"));
+
+  k.TrimAppend(1, p, 3);
+  ASSERT_EQ(std::string(k.GetKey().data(), k.GetKey().size()),
+            std::string("aabc"));
+
+  k.TrimAppend(0, p, 26);
+  ASSERT_EQ(std::string(k.GetKey().data(), k.GetKey().size()),
+            std::string("abcdefghijklmnopqrstuvwxyz"));
+
+  k.TrimAppend(26, q, 10);
+  ASSERT_EQ(std::string(k.GetKey().data(), k.GetKey().size()),
+            std::string("abcdefghijklmnopqrstuvwxyz0123456789"));
+
+  k.TrimAppend(36, q, 1);
+  ASSERT_EQ(std::string(k.GetKey().data(), k.GetKey().size()),
+            std::string("abcdefghijklmnopqrstuvwxyz01234567890"));
+
+  k.TrimAppend(26, q, 1);
+  ASSERT_EQ(std::string(k.GetKey().data(), k.GetKey().size()),
+            std::string("abcdefghijklmnopqrstuvwxyz0"));
+
+  // Size going up, memory allocation is triggered
+  k.TrimAppend(27, p, 26);
+  ASSERT_EQ(std::string(k.GetKey().data(), k.GetKey().size()),
+            std::string("abcdefghijklmnopqrstuvwxyz0"
+              "abcdefghijklmnopqrstuvwxyz"));
+}
+
 }  // namespace rocksdb

 int main(int argc, char** argv) {
@@ -14,21 +14,15 @@

 namespace rocksdb {

-FileIndexer::FileIndexer(const uint32_t num_levels,
-                         const Comparator* ucmp)
-  : num_levels_(num_levels),
-    ucmp_(ucmp),
-    next_level_index_(num_levels),
-    level_rb_(num_levels, -1) {
-}
-
+FileIndexer::FileIndexer(const Comparator* ucmp)
+    : num_levels_(0), ucmp_(ucmp), level_rb_(nullptr) {}

 uint32_t FileIndexer::NumLevelIndex() {
  return next_level_index_.size();
 }

 uint32_t FileIndexer::LevelIndexSize(uint32_t level) {
-  return next_level_index_[level].size();
+  return next_level_index_[level].num_index;
 }

 void FileIndexer::GetNextLevelIndex(
@@ -46,11 +40,13 @@ void FileIndexer::GetNextLevelIndex(
  assert(level < num_levels_ - 1);
  assert(static_cast<int32_t>(file_index) <= level_rb_[level]);

-  const auto& index = next_level_index_[level][file_index];
+  const IndexUnit* index_units = next_level_index_[level].index_units;
+  const auto& index = index_units[file_index];

  if (cmp_smallest < 0) {
-    *left_bound = (level > 0 && file_index > 0) ?
-      next_level_index_[level][file_index - 1].largest_lb : 0;
+    *left_bound = (level > 0 && file_index > 0)
+                      ? index_units[file_index - 1].largest_lb
+                      : 0;
    *right_bound = index.smallest_rb;
  } else if (cmp_smallest == 0) {
    *left_bound = index.smallest_lb;
@@ -73,16 +69,25 @@ void FileIndexer::GetNextLevelIndex(
  assert(*right_bound <= level_rb_[level + 1]);
 }

-void FileIndexer::ClearIndex() {
-  for (uint32_t level = 1; level < num_levels_; ++level) {
-    next_level_index_[level].clear();
-  }
-}
-
-void FileIndexer::UpdateIndex(std::vector<FileMetaData*>* const files) {
+void FileIndexer::UpdateIndex(Arena* arena, const uint32_t num_levels,
+                              std::vector<FileMetaData*>* const files) {
  if (files == nullptr) {
    return;
  }
+  if (num_levels == 0) {  // uint_32 0-1 would cause bad behavior
+    num_levels_ = num_levels;
+    return;
+  }
+  assert(level_rb_ == nullptr);  // level_rb_ should be init here
+
+  num_levels_ = num_levels;
+  next_level_index_.resize(num_levels);
+
+  char* mem = arena->AllocateAligned(num_levels_ * sizeof(int32_t));
+  level_rb_ = new (mem) int32_t[num_levels_];
+  for (size_t i = 0; i < num_levels_; i++) {
+    level_rb_[i] = -1;
+  }

  // L1 - Ln-1
  for (uint32_t level = 1; level < num_levels_ - 1; ++level) {
@@ -93,55 +98,56 @@ void FileIndexer::UpdateIndex(std::vector<FileMetaData*>* const files) {
    if (upper_size == 0) {
      continue;
    }
-    auto& index = next_level_index_[level];
-    index.resize(upper_size);
+    IndexLevel& index_level = next_level_index_[level];
+    index_level.num_index = upper_size;
+    char* mem = arena->AllocateAligned(upper_size * sizeof(IndexUnit));
+    index_level.index_units = new (mem) IndexUnit[upper_size];

-    CalculateLB(upper_files, lower_files, &index,
-        [this](const FileMetaData* a, const FileMetaData* b) -> int {
+    CalculateLB(
+        upper_files, lower_files, &index_level,
+        [this](const FileMetaData * a, const FileMetaData * b)->int {
          return ucmp_->Compare(a->smallest.user_key(), b->largest.user_key());
        },
-        [](IndexUnit* index, int32_t f_idx) {
-          index->smallest_lb = f_idx;
-        });
-    CalculateLB(upper_files, lower_files, &index,
-        [this](const FileMetaData* a, const FileMetaData* b) -> int {
+        [](IndexUnit* index, int32_t f_idx) { index->smallest_lb = f_idx; });
+    CalculateLB(
+        upper_files, lower_files, &index_level,
+        [this](const FileMetaData * a, const FileMetaData * b)->int {
          return ucmp_->Compare(a->largest.user_key(), b->largest.user_key());
        },
-        [](IndexUnit* index, int32_t f_idx) {
-          index->largest_lb = f_idx;
-        });
-    CalculateRB(upper_files, lower_files, &index,
-        [this](const FileMetaData* a, const FileMetaData* b) -> int {
+        [](IndexUnit* index, int32_t f_idx) { index->largest_lb = f_idx; });
+    CalculateRB(
+        upper_files, lower_files, &index_level,
+        [this](const FileMetaData * a, const FileMetaData * b)->int {
          return ucmp_->Compare(a->smallest.user_key(), b->smallest.user_key());
        },
-        [](IndexUnit* index, int32_t f_idx) {
-          index->smallest_rb = f_idx;
-        });
-    CalculateRB(upper_files, lower_files, &index,
-        [this](const FileMetaData* a, const FileMetaData* b) -> int {
+        [](IndexUnit* index, int32_t f_idx) { index->smallest_rb = f_idx; });
+    CalculateRB(
+        upper_files, lower_files, &index_level,
+        [this](const FileMetaData * a, const FileMetaData * b)->int {
          return ucmp_->Compare(a->largest.user_key(), b->smallest.user_key());
        },
-        [](IndexUnit* index, int32_t f_idx) {
-          index->largest_rb = f_idx;
-        });
+        [](IndexUnit* index, int32_t f_idx) { index->largest_rb = f_idx; });
  }
+
  level_rb_[num_levels_ - 1] = files[num_levels_ - 1].size() - 1;
 }

-void FileIndexer::CalculateLB(const std::vector<FileMetaData*>& upper_files,
-    const std::vector<FileMetaData*>& lower_files,
-    std::vector<IndexUnit>* index,
+void FileIndexer::CalculateLB(
+    const std::vector<FileMetaData*>& upper_files,
+    const std::vector<FileMetaData*>& lower_files, IndexLevel* index_level,
    std::function<int(const FileMetaData*, const FileMetaData*)> cmp_op,
    std::function<void(IndexUnit*, int32_t)> set_index) {
  const int32_t upper_size = upper_files.size();
  const int32_t lower_size = lower_files.size();
  int32_t upper_idx = 0;
  int32_t lower_idx = 0;
+
+  IndexUnit* index = index_level->index_units;
  while (upper_idx < upper_size && lower_idx < lower_size) {
    int cmp = cmp_op(upper_files[upper_idx], lower_files[lower_idx]);

    if (cmp == 0) {
-      set_index(&(*index)[upper_idx], lower_idx);
+      set_index(&index[upper_idx], lower_idx);
      ++upper_idx;
      ++lower_idx;
    } else if (cmp > 0) {
@@ -151,7 +157,7 @@ void FileIndexer::CalculateLB(const std::vector<FileMetaData*>& upper_files,
    } else {
      // Lower level's file becomes larger, update the index, and
      // move to the next upper file
-      set_index(&(*index)[upper_idx], lower_idx);
+      set_index(&index[upper_idx], lower_idx);
      ++upper_idx;
    }
  }
@@ -159,25 +165,27 @@ void FileIndexer::CalculateLB(const std::vector<FileMetaData*>& upper_files,
  while (upper_idx < upper_size) {
    // Lower files are exhausted, that means the remaining upper files are
    // greater than any lower files. Set the index to be the lower level size.
-    set_index(&(*index)[upper_idx], lower_size);
+    set_index(&index[upper_idx], lower_size);
    ++upper_idx;
  }
 }

-void FileIndexer::CalculateRB(const std::vector<FileMetaData*>& upper_files,
-    const std::vector<FileMetaData*>& lower_files,
-    std::vector<IndexUnit>* index,
+void FileIndexer::CalculateRB(
+    const std::vector<FileMetaData*>& upper_files,
+    const std::vector<FileMetaData*>& lower_files, IndexLevel* index_level,
    std::function<int(const FileMetaData*, const FileMetaData*)> cmp_op,
    std::function<void(IndexUnit*, int32_t)> set_index) {
  const int32_t upper_size = upper_files.size();
  const int32_t lower_size = lower_files.size();
  int32_t upper_idx = upper_size - 1;
  int32_t lower_idx = lower_size - 1;
+
+  IndexUnit* index = index_level->index_units;
  while (upper_idx >= 0 && lower_idx >= 0) {
    int cmp = cmp_op(upper_files[upper_idx], lower_files[lower_idx]);

    if (cmp == 0) {
-      set_index(&(*index)[upper_idx], lower_idx);
+      set_index(&index[upper_idx], lower_idx);
      --upper_idx;
      --lower_idx;
    } else if (cmp < 0) {
@@ -187,14 +195,14 @@ void FileIndexer::CalculateRB(const std::vector<FileMetaData*>& upper_files,
    } else {
      // Lower level's file becomes smaller, update the index, and move to
      // the next the upper file
-      set_index(&(*index)[upper_idx], lower_idx);
+      set_index(&index[upper_idx], lower_idx);
      --upper_idx;
    }
  }
  while (upper_idx >= 0) {
    // Lower files are exhausted, that means the remaining upper files are
    // smaller than any lower files. Set it to -1.
-    set_index(&(*index)[upper_idx], -1);
+    set_index(&index[upper_idx], -1);
    --upper_idx;
  }
 }
@@ -12,11 +12,15 @@
 #include <functional>
 #include <limits>
 #include <vector>
+#include "util/arena.h"
+#include "util/autovector.h"

 namespace rocksdb {

 class Comparator;
 struct FileMetaData;
+struct FdWithKeyRange;
+struct FileLevel;

 // The file tree structure in Version is prebuilt and the range of each file
 // is known. On Version::Get(), it uses binary search to find a potential file
@@ -36,7 +40,7 @@ struct FileMetaData;
 // naive approach.
 class FileIndexer {
 public:
-  FileIndexer(const uint32_t num_levels, const Comparator* ucmp);
+  explicit FileIndexer(const Comparator* ucmp);

  uint32_t NumLevelIndex();

@@ -50,16 +54,15 @@ class FileIndexer {
    const uint32_t level, const uint32_t file_index, const int cmp_smallest,
    const int cmp_largest, int32_t* left_bound, int32_t* right_bound);

-  void ClearIndex();
-
-  void UpdateIndex(std::vector<FileMetaData*>* const files);
+  void UpdateIndex(Arena* arena, const uint32_t num_levels,
+                   std::vector<FileMetaData*>* const files);

  enum {
    kLevelMaxIndex = std::numeric_limits<int32_t>::max()
  };

 private:
-  const uint32_t num_levels_;
+  uint32_t num_levels_;
  const Comparator* ucmp_;

  struct IndexUnit {
@@ -110,20 +113,28 @@ class FileIndexer {
    int32_t largest_rb;
  };

-  void CalculateLB(const std::vector<FileMetaData*>& upper_files,
-    const std::vector<FileMetaData*>& lower_files,
-    std::vector<IndexUnit>* index,
-    std::function<int(const FileMetaData*, const FileMetaData*)> cmp_op,
-    std::function<void(IndexUnit*, int32_t)> set_index);
+  // Data structure to store IndexUnits in a whole level
+  struct IndexLevel {
+    size_t num_index;
+    IndexUnit* index_units;

-  void CalculateRB(const std::vector<FileMetaData*>& upper_files,
-    const std::vector<FileMetaData*>& lower_files,
-    std::vector<IndexUnit>* index,
-    std::function<int(const FileMetaData*, const FileMetaData*)> cmp_op,
-    std::function<void(IndexUnit*, int32_t)> set_index);
+    IndexLevel() : num_index(0), index_units(nullptr) {}
+  };

-  std::vector<std::vector<IndexUnit>> next_level_index_;
-  std::vector<int32_t> level_rb_;
+  void CalculateLB(
+      const std::vector<FileMetaData*>& upper_files,
+      const std::vector<FileMetaData*>& lower_files, IndexLevel* index_level,
+      std::function<int(const FileMetaData*, const FileMetaData*)> cmp_op,
+      std::function<void(IndexUnit*, int32_t)> set_index);
+
+  void CalculateRB(
+      const std::vector<FileMetaData*>& upper_files,
+      const std::vector<FileMetaData*>& lower_files, IndexLevel* index_level,
+      std::function<int(const FileMetaData*, const FileMetaData*)> cmp_op,
+      std::function<void(IndexUnit*, int32_t)> set_index);
+
+  autovector<IndexLevel> next_level_index_;
+  int32_t* level_rb_;
 };

 }  // namespace rocksdb
@@ -35,16 +35,13 @@ class IntComparator : public Comparator {
  void FindShortSuccessor(std::string* key) const {}
 };

-
 struct FileIndexerTest {
 public:
-  FileIndexerTest() :
-    kNumLevels(4), indexer(kNumLevels, &ucmp),
-    files(new std::vector<FileMetaData*>[kNumLevels]) {
-  }
+  FileIndexerTest()
+      : kNumLevels(4), files(new std::vector<FileMetaData*>[kNumLevels]) {}

  ~FileIndexerTest() {
-    Reset();
+    ClearFiles();
    delete[] files;
  }

@@ -59,14 +56,13 @@ struct FileIndexerTest {
    return InternalKey(Slice(reinterpret_cast<char*>(&v), 8), 0, kTypeValue);
  }

-  void Reset() {
+  void ClearFiles() {
    for (uint32_t i = 0; i < kNumLevels; ++i) {
      for (auto* f : files[i]) {
        delete f;
      }
      files[i].clear();
    }
-    indexer.ClearIndex();
  }

  void GetNextLevelIndex(const uint32_t level, const uint32_t file_index,
@@ -74,23 +70,32 @@ struct FileIndexerTest {
      int32_t* right_index) {
    *left_index = 100;
    *right_index = 100;
-    indexer.GetNextLevelIndex(level, file_index, cmp_smallest, cmp_largest,
-        left_index, right_index);
+    indexer->GetNextLevelIndex(level, file_index, cmp_smallest, cmp_largest,
+                               left_index, right_index);
  }

+  int32_t left = 100;
+  int32_t right = 100;
  const uint32_t kNumLevels;
  IntComparator ucmp;
-  FileIndexer indexer;
+  FileIndexer* indexer;

  std::vector<FileMetaData*>* files;
 };

-TEST(FileIndexerTest, next_level_hint) {
-  for (uint32_t i = 0; i < kNumLevels; ++i) {
-    ASSERT_EQ(0U, indexer.LevelIndexSize(i));
-  }
+// Case 0: Empty
+TEST(FileIndexerTest, Empty) {
+  Arena arena;
+  indexer = new FileIndexer(&ucmp);
+  indexer->UpdateIndex(&arena, 0, files);
+  delete indexer;
+}

-  // Case 1: no overlap, files are on the left of next level files
+// Case 1: no overlap, files are on the left of next level files
+TEST(FileIndexerTest, no_overlap_left) {
+  Arena arena;
+  uint32_t kNumLevels = 4;
+  indexer = new FileIndexer(&ucmp);
  // level 1
  AddFile(1, 100, 200);
  AddFile(1, 300, 400);
@@ -103,9 +108,7 @@ TEST(FileIndexerTest, next_level_hint) {
  AddFile(3, 2500, 2600);
  AddFile(3, 2601, 2699);
  AddFile(3, 2700, 2800);
-  indexer.UpdateIndex(files);
-  int32_t left = 100;
-  int32_t right = 100;
+  indexer->UpdateIndex(&arena, kNumLevels, files);
  for (uint32_t level = 1; level < 3; ++level) {
    for (uint32_t f = 0; f < 3; ++f) {
      GetNextLevelIndex(level, f, -1, -1, &left, &right);
@@ -125,12 +128,15 @@ TEST(FileIndexerTest, next_level_hint) {
      ASSERT_EQ(2, right);
    }
  }
+  delete indexer;
+  ClearFiles();
+}

-  // Case 2: no overlap, files are on the right of next level files
-  Reset();
-  for (uint32_t i = 1; i < kNumLevels; ++i) {
-    ASSERT_EQ(0U, indexer.LevelIndexSize(i));
-  }
+// Case 2: no overlap, files are on the right of next level files
+TEST(FileIndexerTest, no_overlap_right) {
+  Arena arena;
+  uint32_t kNumLevels = 4;
+  indexer = new FileIndexer(&ucmp);
  // level 1
  AddFile(1, 2100, 2200);
  AddFile(1, 2300, 2400);
@@ -143,7 +149,7 @@ TEST(FileIndexerTest, next_level_hint) {
  AddFile(3, 500, 600);
  AddFile(3, 501, 699);
  AddFile(3, 700, 800);
-  indexer.UpdateIndex(files);
+  indexer->UpdateIndex(&arena, kNumLevels, files);
  for (uint32_t level = 1; level < 3; ++level) {
    for (uint32_t f = 0; f < 3; ++f) {
      GetNextLevelIndex(level, f, -1, -1, &left, &right);
@@ -166,11 +172,16 @@ TEST(FileIndexerTest, next_level_hint) {
      ASSERT_EQ(2, right);
    }
  }
+  delete indexer;
+}

-  // Case 3: empty L2
-  Reset();
+// Case 3: empty L2
+TEST(FileIndexerTest, empty_L2) {
+  Arena arena;
+  uint32_t kNumLevels = 4;
+  indexer = new FileIndexer(&ucmp);
  for (uint32_t i = 1; i < kNumLevels; ++i) {
-    ASSERT_EQ(0U, indexer.LevelIndexSize(i));
+    ASSERT_EQ(0U, indexer->LevelIndexSize(i));
  }
  // level 1
  AddFile(1, 2100, 2200);
@@ -180,7 +191,7 @@ TEST(FileIndexerTest, next_level_hint) {
  AddFile(3, 500, 600);
  AddFile(3, 501, 699);
  AddFile(3, 700, 800);
-  indexer.UpdateIndex(files);
+  indexer->UpdateIndex(&arena, kNumLevels, files);
  for (uint32_t f = 0; f < 3; ++f) {
    GetNextLevelIndex(1, f, -1, -1, &left, &right);
    ASSERT_EQ(0, left);
@@ -201,13 +212,14 @@ TEST(FileIndexerTest, next_level_hint) {
    ASSERT_EQ(0, left);
    ASSERT_EQ(-1, right);
  }
+  delete indexer;
+  ClearFiles();
+}

-
-  // Case 4: mixed
-  Reset();
-  for (uint32_t i = 1; i < kNumLevels; ++i) {
-    ASSERT_EQ(0U, indexer.LevelIndexSize(i));
-  }
+// Case 4: mixed
+TEST(FileIndexerTest, mixed) {
+  Arena arena;
+  indexer = new FileIndexer(&ucmp);
  // level 1
  AddFile(1, 100, 200);
  AddFile(1, 250, 400);
@@ -222,7 +234,7 @@ TEST(FileIndexerTest, next_level_hint) {
  AddFile(3, 0, 50);
  AddFile(3, 100, 200);
  AddFile(3, 201, 250);
-  indexer.UpdateIndex(files);
+  indexer->UpdateIndex(&arena, kNumLevels, files);
  // level 1, 0
  GetNextLevelIndex(1, 0, -1, -1, &left, &right);
  ASSERT_EQ(0, left);
@@ -321,6 +333,8 @@ TEST(FileIndexerTest, next_level_hint) {
    ASSERT_EQ(3, left);
    ASSERT_EQ(2, right);
  }
+  delete indexer;
+  ClearFiles();
 }

 }  // namespace rocksdb
@@ -11,6 +11,7 @@

 #include <ctype.h>
 #include <stdio.h>
+#include <vector>
 #include "db/dbformat.h"
 #include "rocksdb/env.h"
 #include "util/logging.h"
@@ -66,9 +67,28 @@ std::string ArchivedLogFileName(const std::string& name, uint64_t number) {
  return MakeFileName(name + "/" + ARCHIVAL_DIR, number, "log");
 }

-std::string TableFileName(const std::string& name, uint64_t number) {
+std::string MakeTableFileName(const std::string& path, uint64_t number) {
+  return MakeFileName(path, number, "sst");
+}
+
+std::string TableFileName(const std::vector<DbPath>& db_paths, uint64_t number,
+                          uint32_t path_id) {
  assert(number > 0);
-  return MakeFileName(name, number, "sst");
+  std::string path;
+  if (path_id >= db_paths.size()) {
+    path = db_paths.back().path;
+  } else {
+    path = db_paths[path_id].path;
+  }
+  return MakeTableFileName(path, number);
+}
+
+std::string FormatFileNumber(uint64_t number, uint32_t path_id) {
+  if (path_id == 0) {
+    return std::to_string(number);
+  } else {
+    return std::to_string(number) + "(path " + std::to_string(path_id) + ")";
+  }
 }

 std::string DescriptorFileName(const std::string& dbname, uint64_t number) {
@@ -226,7 +246,8 @@ bool ParseFileName(const std::string& fname,
 }

 Status SetCurrentFile(Env* env, const std::string& dbname,
-                      uint64_t descriptor_number) {
+                      uint64_t descriptor_number,
+                      Directory* directory_to_fsync) {
  // Remove leading "dbname/" and add newline to manifest file name
  std::string manifest = DescriptorFileName(dbname, descriptor_number);
  Slice contents = manifest;
@@ -237,7 +258,11 @@ Status SetCurrentFile(Env* env, const std::string& dbname,
  if (s.ok()) {
    s = env->RenameFile(tmp, CurrentFileName(dbname));
  }
-  if (!s.ok()) {
+  if (s.ok()) {
+    if (directory_to_fsync != nullptr) {
+      directory_to_fsync->Fsync();
+    }
+  } else {
    env->DeleteFile(tmp);
  }
  return s;
@@ -11,7 +11,9 @@

 #pragma once
 #include <stdint.h>
+#include <unordered_map>
 #include <string>
+#include <vector>
 #include "rocksdb/slice.h"
 #include "rocksdb/status.h"
 #include "rocksdb/transaction_log.h"
@@ -20,6 +22,7 @@
 namespace rocksdb {

 class Env;
+class Directory;

 enum FileType {
  kLogFile,
@@ -33,6 +36,9 @@ enum FileType {
  kIdentityFile
 };

+// map from file number to path ID.
+typedef std::unordered_map<uint64_t, uint32_t> FileNumToPathIdMap;
+
 // Return the name of the log file with the specified number
 // in the db named by "dbname".  The result will be prefixed with
 // "dbname".
@@ -47,10 +53,15 @@ extern std::string ArchivalDirectory(const std::string& dbname);
 extern std::string ArchivedLogFileName(const std::string& dbname,
                                       uint64_t num);

+extern std::string MakeTableFileName(const std::string& name, uint64_t number);
+
 // Return the name of the sstable with the specified number
 // in the db named by "dbname".  The result will be prefixed with
 // "dbname".
-extern std::string TableFileName(const std::string& dbname, uint64_t number);
+extern std::string TableFileName(const std::vector<DbPath>& db_paths,
+                                 uint64_t number, uint32_t path_id);
+
+extern std::string FormatFileNumber(uint64_t number, uint32_t path_id);

 // Return the name of the descriptor file for the db named by
 // "dbname" and the specified incarnation number.  The result will be
@@ -100,7 +111,8 @@ extern bool ParseFileName(const std::string& filename,
 // Make the CURRENT file point to the descriptor file with the
 // specified number.
 extern Status SetCurrentFile(Env* env, const std::string& dbname,
-                             uint64_t descriptor_number);
+                             uint64_t descriptor_number,
+                             Directory* directory_to_fsync);

 // Make the IDENTITY file for the db
 extern Status SetIdentityFile(Env* env, const std::string& dbname);
@@ -108,7 +108,10 @@ TEST(FileNameTest, Construction) {
  ASSERT_EQ(192U, number);
  ASSERT_EQ(kLogFile, type);

-  fname = TableFileName("bar", 200);
+  fname = TableFileName({DbPath("bar", 0)}, 200, 0);
+  std::string fname1 =
+      TableFileName({DbPath("foo", 0), DbPath("bar", 0)}, 200, 1);
+  ASSERT_EQ(fname, fname1);
  ASSERT_EQ("bar/", std::string(fname.data(), 4));
  ASSERT_TRUE(ParseFileName(fname.c_str() + 4, &number, &type));
  ASSERT_EQ(200U, number);
@@ -0,0 +1,463 @@
+//  Copyright (c) 2013, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under the BSD-style license found in the
+//  LICENSE file in the root directory of this source tree. An additional grant
+//  of patent rights can be found in the PATENTS file in the same directory.
+
+#ifndef ROCKSDB_LITE
+#include "db/forward_iterator.h"
+
+#include <string>
+#include <utility>
+#include <limits>
+#include "db/db_impl.h"
+#include "db/db_iter.h"
+#include "db/column_family.h"
+#include "rocksdb/env.h"
+#include "rocksdb/slice.h"
+#include "rocksdb/slice_transform.h"
+#include "table/merger.h"
+#include "db/dbformat.h"
+
+namespace rocksdb {
+
+// Usage:
+//     LevelIterator iter;
+//     iter.SetFileIndex(file_index);
+//     iter.Seek(target);
+//     iter.Next()
+class LevelIterator : public Iterator {
+ public:
+  LevelIterator(const ColumnFamilyData* const cfd,
+      const ReadOptions& read_options,
+      const std::vector<FileMetaData*>& files)
+    : cfd_(cfd), read_options_(read_options), files_(files), valid_(false),
+      file_index_(std::numeric_limits<uint32_t>::max()) {}
+
+  void SetFileIndex(uint32_t file_index) {
+    assert(file_index < files_.size());
+    if (file_index != file_index_) {
+      file_index_ = file_index;
+      file_iter_.reset(cfd_->table_cache()->NewIterator(
+          read_options_, *(cfd_->soptions()), cfd_->internal_comparator(),
+          files_[file_index_]->fd, nullptr /* table_reader_ptr */, false));
+    }
+    valid_ = false;
+  }
+  void SeekToLast() override {
+    status_ = Status::NotSupported("LevelIterator::SeekToLast()");
+    valid_ = false;
+  }
+  void Prev() {
+    status_ = Status::NotSupported("LevelIterator::Prev()");
+    valid_ = false;
+  }
+  bool Valid() const override {
+    return valid_;
+  }
+  void SeekToFirst() override {
+    SetFileIndex(0);
+    file_iter_->SeekToFirst();
+    valid_ = file_iter_->Valid();
+  }
+  void Seek(const Slice& internal_key) override {
+    assert(file_iter_ != nullptr);
+    file_iter_->Seek(internal_key);
+    valid_ = file_iter_->Valid();
+    assert(valid_);
+  }
+  void Next() override {
+    assert(valid_);
+    file_iter_->Next();
+    while (!file_iter_->Valid()) {
+      if (file_index_ + 1 >= files_.size()) {
+        valid_ = false;
+        return;
+      }
+      SetFileIndex(file_index_ + 1);
+      file_iter_->SeekToFirst();
+    }
+    valid_ = file_iter_->Valid();
+  }
+  Slice key() const override {
+    assert(valid_);
+    return file_iter_->key();
+  }
+  Slice value() const override {
+    assert(valid_);
+    return file_iter_->value();
+  }
+  Status status() const override {
+    if (!status_.ok()) {
+      return status_;
+    } else if (file_iter_ && !file_iter_->status().ok()) {
+      return file_iter_->status();
+    }
+    return Status::OK();
+  }
+
+ private:
+  const ColumnFamilyData* const cfd_;
+  const ReadOptions& read_options_;
+  const std::vector<FileMetaData*>& files_;
+
+  bool valid_;
+  uint32_t file_index_;
+  Status status_;
+  std::unique_ptr<Iterator> file_iter_;
+};
+
+ForwardIterator::ForwardIterator(DBImpl* db, const ReadOptions& read_options,
+                                 ColumnFamilyData* cfd)
+    : db_(db),
+      read_options_(read_options),
+      cfd_(cfd),
+      prefix_extractor_(cfd->options()->prefix_extractor.get()),
+      user_comparator_(cfd->user_comparator()),
+      immutable_min_heap_(MinIterComparator(&cfd_->internal_comparator())),
+      sv_(nullptr),
+      mutable_iter_(nullptr),
+      current_(nullptr),
+      valid_(false),
+      is_prev_set_(false) {}
+
+ForwardIterator::~ForwardIterator() {
+  Cleanup();
+}
+
+void ForwardIterator::Cleanup() {
+  delete mutable_iter_;
+  for (auto* m : imm_iters_) {
+    delete m;
+  }
+  imm_iters_.clear();
+  for (auto* f : l0_iters_) {
+    delete f;
+  }
+  l0_iters_.clear();
+  for (auto* l : level_iters_) {
+    delete l;
+  }
+  level_iters_.clear();
+
+  if (sv_ != nullptr && sv_->Unref()) {
+    DBImpl::DeletionState deletion_state;
+    db_->mutex_.Lock();
+    sv_->Cleanup();
+    db_->FindObsoleteFiles(deletion_state, false, true);
+    db_->mutex_.Unlock();
+    delete sv_;
+    if (deletion_state.HaveSomethingToDelete()) {
+      db_->PurgeObsoleteFiles(deletion_state);
+    }
+  }
+}
+
+bool ForwardIterator::Valid() const {
+  return valid_;
+}
+
+void ForwardIterator::SeekToFirst() {
+  if (sv_ == nullptr ||
+      sv_ ->version_number != cfd_->GetSuperVersionNumber()) {
+    RebuildIterators();
+  }
+  SeekInternal(Slice(), true);
+}
+
+void ForwardIterator::Seek(const Slice& internal_key) {
+  if (sv_ == nullptr ||
+      sv_ ->version_number != cfd_->GetSuperVersionNumber()) {
+    RebuildIterators();
+  }
+  SeekInternal(internal_key, false);
+}
+
+void ForwardIterator::SeekInternal(const Slice& internal_key,
+                                   bool seek_to_first) {
+  // mutable
+  seek_to_first ? mutable_iter_->SeekToFirst() :
+                  mutable_iter_->Seek(internal_key);
+
+  // immutable
+  // TODO(ljin): NeedToSeekImmutable has negative impact on performance
+  // if it turns to need to seek immutable often. We probably want to have
+  // an option to turn it off.
+  if (seek_to_first || NeedToSeekImmutable(internal_key)) {
+    {
+      auto tmp = MinIterHeap(MinIterComparator(&cfd_->internal_comparator()));
+      immutable_min_heap_.swap(tmp);
+    }
+    for (auto* m : imm_iters_) {
+      seek_to_first ? m->SeekToFirst() : m->Seek(internal_key);
+      if (m->Valid()) {
+        immutable_min_heap_.push(m);
+      }
+    }
+
+    Slice user_key;
+    if (!seek_to_first) {
+      user_key = ExtractUserKey(internal_key);
+    }
+    auto* files = sv_->current->files_;
+    for (uint32_t i = 0; i < files[0].size(); ++i) {
+      if (seek_to_first) {
+        l0_iters_[i]->SeekToFirst();
+      } else {
+        // If the target key passes over the larget key, we are sure Next()
+        // won't go over this file.
+        if (user_comparator_->Compare(user_key,
+              files[0][i]->largest.user_key()) > 0) {
+          continue;
+        }
+        l0_iters_[i]->Seek(internal_key);
+      }
+      if (l0_iters_[i]->Valid()) {
+        immutable_min_heap_.push(l0_iters_[i]);
+      }
+    }
+
+    int32_t search_left_bound = 0;
+    int32_t search_right_bound = FileIndexer::kLevelMaxIndex;
+    for (int32_t level = 1; level < sv_->current->NumberLevels(); ++level) {
+      if (files[level].empty()) {
+        search_left_bound = 0;
+        search_right_bound = FileIndexer::kLevelMaxIndex;
+        continue;
+      }
+      assert(level_iters_[level - 1] != nullptr);
+      uint32_t f_idx = 0;
+      if (!seek_to_first) {
+        // TODO(ljin): remove before committing
+        // f_idx = FindFileInRange(
+        //    files[level], internal_key, 0, files[level].size());
+
+        if (search_left_bound == search_right_bound) {
+          f_idx = search_left_bound;
+        } else if (search_left_bound < search_right_bound) {
+          f_idx = FindFileInRange(
+              files[level], internal_key, search_left_bound,
+              search_right_bound == FileIndexer::kLevelMaxIndex ?
+                files[level].size() : search_right_bound);
+        } else {
+          // search_left_bound > search_right_bound
+          // There are only 2 cases this can happen:
+          // (1) target key is smaller than left most file
+          // (2) target key is larger than right most file
+          assert(search_left_bound == (int32_t)files[level].size() ||
+                 search_right_bound == -1);
+          if (search_right_bound == -1) {
+            assert(search_left_bound == 0);
+            f_idx = 0;
+          } else {
+            sv_->current->file_indexer_.GetNextLevelIndex(
+                level, files[level].size() - 1,
+                1, 1, &search_left_bound, &search_right_bound);
+            continue;
+          }
+        }
+
+        // Prepare hints for the next level
+        if (f_idx < files[level].size()) {
+          int cmp_smallest = user_comparator_->Compare(
+              user_key, files[level][f_idx]->smallest.user_key());
+          int cmp_largest = -1;
+          if (cmp_smallest >= 0) {
+            cmp_smallest = user_comparator_->Compare(
+                user_key, files[level][f_idx]->smallest.user_key());
+          }
+          sv_->current->file_indexer_.GetNextLevelIndex(level, f_idx,
+              cmp_smallest, cmp_largest,
+              &search_left_bound, &search_right_bound);
+        } else {
+          sv_->current->file_indexer_.GetNextLevelIndex(
+              level, files[level].size() - 1,
+              1, 1, &search_left_bound, &search_right_bound);
+        }
+      }
+
+      // Seek
+      if (f_idx < files[level].size()) {
+        level_iters_[level - 1]->SetFileIndex(f_idx);
+        seek_to_first ? level_iters_[level - 1]->SeekToFirst() :
+                        level_iters_[level - 1]->Seek(internal_key);
+        if (level_iters_[level - 1]->Valid()) {
+          immutable_min_heap_.push(level_iters_[level - 1]);
+        }
+      }
+    }
+
+    if (seek_to_first || immutable_min_heap_.empty()) {
+      is_prev_set_ = false;
+    } else {
+      prev_key_.SetKey(internal_key);
+      is_prev_set_ = true;
+    }
+  } else if (current_ && current_ != mutable_iter_) {
+    // current_ is one of immutable iterators, push it back to the heap
+    immutable_min_heap_.push(current_);
+  }
+
+  UpdateCurrent();
+}
+
+void ForwardIterator::Next() {
+  assert(valid_);
+
+  if (sv_ == nullptr ||
+      sv_ ->version_number != cfd_->GetSuperVersionNumber()) {
+    std::string current_key = key().ToString();
+    Slice old_key(current_key.data(), current_key.size());
+
+    RebuildIterators();
+    SeekInternal(old_key, false);
+    if (!valid_ || key().compare(old_key) != 0) {
+      return;
+    }
+  } else if (current_ != mutable_iter_) {
+    // It is going to advance immutable iterator
+    prev_key_.SetKey(current_->key());
+    is_prev_set_ = true;
+  }
+
+  current_->Next();
+  if (current_->Valid() && current_ != mutable_iter_) {
+    immutable_min_heap_.push(current_);
+  }
+  UpdateCurrent();
+}
+
+Slice ForwardIterator::key() const {
+  assert(valid_);
+  return current_->key();
+}
+
+Slice ForwardIterator::value() const {
+  assert(valid_);
+  return current_->value();
+}
+
+Status ForwardIterator::status() const {
+  if (!status_.ok()) {
+    return status_;
+  } else if (!mutable_iter_->status().ok()) {
+    return mutable_iter_->status();
+  }
+
+  for (auto *it : imm_iters_) {
+    if (it && !it->status().ok()) {
+      return it->status();
+    }
+  }
+  for (auto *it : l0_iters_) {
+    if (it && !it->status().ok()) {
+      return it->status();
+    }
+  }
+  for (auto *it : level_iters_) {
+    if (it && !it->status().ok()) {
+      return it->status();
+    }
+  }
+
+  return Status::OK();
+}
+
+void ForwardIterator::RebuildIterators() {
+  // Clean up
+  Cleanup();
+  // New
+  sv_ = cfd_->GetReferencedSuperVersion(&(db_->mutex_));
+  mutable_iter_ = sv_->mem->NewIterator(read_options_);
+  sv_->imm->AddIterators(read_options_, &imm_iters_);
+  const auto& l0_files = sv_->current->files_[0];
+  l0_iters_.reserve(l0_files.size());
+  for (const auto* l0 : l0_files) {
+    l0_iters_.push_back(cfd_->table_cache()->NewIterator(
+        read_options_, *cfd_->soptions(), cfd_->internal_comparator(), l0->fd));
+  }
+  level_iters_.reserve(sv_->current->NumberLevels() - 1);
+  for (int32_t level = 1; level < sv_->current->NumberLevels(); ++level) {
+    if (sv_->current->files_[level].empty()) {
+      level_iters_.push_back(nullptr);
+    } else {
+      level_iters_.push_back(new LevelIterator(cfd_, read_options_,
+          sv_->current->files_[level]));
+    }
+  }
+
+  current_ = nullptr;
+  is_prev_set_ = false;
+}
+
+void ForwardIterator::UpdateCurrent() {
+  if (immutable_min_heap_.empty() && !mutable_iter_->Valid()) {
+    current_ = nullptr;
+  } else if (immutable_min_heap_.empty()) {
+    current_ = mutable_iter_;
+  } else if (!mutable_iter_->Valid()) {
+    current_ = immutable_min_heap_.top();
+    immutable_min_heap_.pop();
+  } else {
+    current_ = immutable_min_heap_.top();
+    assert(current_ != nullptr);
+    assert(current_->Valid());
+    int cmp = cfd_->internal_comparator().InternalKeyComparator::Compare(
+        mutable_iter_->key(), current_->key());
+    assert(cmp != 0);
+    if (cmp > 0) {
+      immutable_min_heap_.pop();
+    } else {
+      current_ = mutable_iter_;
+    }
+  }
+  valid_ = (current_ != nullptr);
+  if (!status_.ok()) {
+    status_ = Status::OK();
+  }
+}
+
+bool ForwardIterator::NeedToSeekImmutable(const Slice& target) {
+  if (!is_prev_set_) {
+    return true;
+  }
+  Slice prev_key = prev_key_.GetKey();
+  if (prefix_extractor_ && prefix_extractor_->Transform(target).compare(
+    prefix_extractor_->Transform(prev_key)) != 0) {
+    return true;
+  }
+  if (cfd_->internal_comparator().InternalKeyComparator::Compare(
+        prev_key, target) >= 0) {
+    return true;
+  }
+  if (immutable_min_heap_.empty() ||
+      cfd_->internal_comparator().InternalKeyComparator::Compare(
+          target, current_ == mutable_iter_ ? immutable_min_heap_.top()->key()
+                                            : current_->key()) > 0) {
+    return true;
+  }
+  return false;
+}
+
+uint32_t ForwardIterator::FindFileInRange(
+    const std::vector<FileMetaData*>& files, const Slice& internal_key,
+    uint32_t left, uint32_t right) {
+  while (left < right) {
+    uint32_t mid = (left + right) / 2;
+    const FileMetaData* f = files[mid];
+    if (cfd_->internal_comparator().InternalKeyComparator::Compare(
+          f->largest.Encode(), internal_key) < 0) {
+      // Key at "mid.largest" is < "target".  Therefore all
+      // files at or before "mid" are uninteresting.
+      left = mid + 1;
+    } else {
+      // Key at "mid.largest" is >= "target".  Therefore all files
+      // after "mid" are uninteresting.
+      right = mid;
+    }
+  }
+  return right;
+}
+
+}  // namespace rocksdb
+
+#endif  // ROCKSDB_LITE
@@ -0,0 +1,105 @@
+//  Copyright (c) 2013, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under the BSD-style license found in the
+//  LICENSE file in the root directory of this source tree. An additional grant
+//  of patent rights can be found in the PATENTS file in the same directory.
+#pragma once
+
+#ifndef ROCKSDB_LITE
+
+#include <string>
+#include <vector>
+#include <queue>
+
+#include "rocksdb/db.h"
+#include "rocksdb/iterator.h"
+#include "rocksdb/options.h"
+#include "db/dbformat.h"
+
+namespace rocksdb {
+
+class DBImpl;
+class Env;
+struct SuperVersion;
+class ColumnFamilyData;
+class LevelIterator;
+struct FileMetaData;
+
+class MinIterComparator {
+ public:
+  explicit MinIterComparator(const Comparator* comparator) :
+    comparator_(comparator) {}
+
+  bool operator()(Iterator* a, Iterator* b) {
+    return comparator_->Compare(a->key(), b->key()) > 0;
+  }
+ private:
+  const Comparator* comparator_;
+};
+
+typedef std::priority_queue<Iterator*,
+          std::vector<Iterator*>,
+          MinIterComparator> MinIterHeap;
+
+/**
+ * ForwardIterator is a special type of iterator that only supports Seek()
+ * and Next(). It is expected to perform better than TailingIterator by
+ * removing the encapsulation and making all information accessible within
+ * the iterator. At the current implementation, snapshot is taken at the
+ * time Seek() is called. The Next() followed do not see new values after.
+ */
+class ForwardIterator : public Iterator {
+ public:
+  ForwardIterator(DBImpl* db, const ReadOptions& read_options,
+                  ColumnFamilyData* cfd);
+  virtual ~ForwardIterator();
+
+  void SeekToLast() override {
+    status_ = Status::NotSupported("ForwardIterator::SeekToLast()");
+    valid_ = false;
+  }
+  void Prev() {
+    status_ = Status::NotSupported("ForwardIterator::Prev");
+    valid_ = false;
+  }
+
+  virtual bool Valid() const override;
+  void SeekToFirst() override;
+  virtual void Seek(const Slice& target) override;
+  virtual void Next() override;
+  virtual Slice key() const override;
+  virtual Slice value() const override;
+  virtual Status status() const override;
+
+ private:
+  void Cleanup();
+  void RebuildIterators();
+  void SeekInternal(const Slice& internal_key, bool seek_to_first);
+  void UpdateCurrent();
+  bool NeedToSeekImmutable(const Slice& internal_key);
+  uint32_t FindFileInRange(
+    const std::vector<FileMetaData*>& files, const Slice& internal_key,
+    uint32_t left, uint32_t right);
+
+  DBImpl* const db_;
+  const ReadOptions read_options_;
+  ColumnFamilyData* const cfd_;
+  const SliceTransform* const prefix_extractor_;
+  const Comparator* user_comparator_;
+  MinIterHeap immutable_min_heap_;
+
+  SuperVersion* sv_;
+  Iterator* mutable_iter_;
+  std::vector<Iterator*> imm_iters_;
+  std::vector<Iterator*> l0_iters_;
+  std::vector<LevelIterator*> level_iters_;
+  Iterator* current_;
+  // internal iterator status
+  Status status_;
+  bool valid_;
+
+  IterKey prev_key_;
+  bool is_prev_set_;
+};
+
+}  // namespace rocksdb
+#endif  // ROCKSDB_LITE
@@ -7,16 +7,96 @@
 // found in the LICENSE file. See the AUTHORS file for names of contributors.

 #include "db/internal_stats.h"
-#include "db/column_family.h"
-
+#define __STDC_FORMAT_MACROS
+#include <inttypes.h>
 #include <vector>
+#include "db/column_family.h"

 namespace rocksdb {

-DBPropertyType GetPropertyType(const Slice& property) {
+namespace {
+const double kMB = 1048576.0;
+const double kGB = kMB * 1024;
+
+void PrintLevelStatsHeader(char* buf, size_t len, const std::string& cf_name) {
+  snprintf(
+      buf, len,
+      "\n** Compaction Stats [%s] **\n"
+      "Level   Files   Size(MB) Score Read(GB)  Rn(GB) Rnp1(GB) "
+      "Write(GB) Wnew(GB) RW-Amp W-Amp Rd(MB/s) Wr(MB/s)  Rn(cnt) "
+      "Rnp1(cnt) Wnp1(cnt) Wnew(cnt)  Comp(sec) Comp(cnt) Avg(sec) "
+      "Stall(sec) Stall(cnt) Avg(ms)\n"
+      "--------------------------------------------------------------------"
+      "--------------------------------------------------------------------"
+      "--------------------------------------------------------------------\n",
+      cf_name.c_str());
+}
+
+void PrintLevelStats(char* buf, size_t len, const std::string& name,
+    int num_files, int being_compacted, double total_file_size, double score,
+    double rw_amp, double w_amp, double stall_us, uint64_t stalls,
+    const InternalStats::CompactionStats& stats) {
+  uint64_t bytes_read = stats.bytes_readn + stats.bytes_readnp1;
+  uint64_t bytes_new = stats.bytes_written - stats.bytes_readnp1;
+  double elapsed = (stats.micros + 1) / 1000000.0;
+
+  snprintf(buf, len,
+    "%4s %5d/%-3d %8.0f %5.1f " /* Level, Files, Size(MB), Score */
+    "%8.1f " /* Read(GB) */
+    "%7.1f " /* Rn(GB) */
+    "%8.1f " /* Rnp1(GB) */
+    "%9.1f " /* Write(GB) */
+    "%8.1f " /* Wnew(GB) */
+    "%6.1f " /* RW-Amp */
+    "%5.1f " /* W-Amp */
+    "%8.1f " /* Rd(MB/s) */
+    "%8.1f " /* Wr(MB/s) */
+    "%8d " /* Rn(cnt) */
+    "%9d " /* Rnp1(cnt) */
+    "%9d " /* Wnp1(cnt) */
+    "%9d " /* Wnew(cnt) */
+    "%10.0f " /* Comp(sec) */
+    "%9d " /* Comp(cnt) */
+    "%8.3f " /* Avg(sec) */
+    "%10.2f " /* Stall(sec) */
+    "%10" PRIu64 " " /* Stall(cnt) */
+    "%7.2f\n" /* Avg(ms) */,
+    name.c_str(), num_files, being_compacted, total_file_size / kMB, score,
+    bytes_read / kGB,
+    stats.bytes_readn / kGB,
+    stats.bytes_readnp1 / kGB,
+    stats.bytes_written / kGB,
+    bytes_new / kGB,
+    rw_amp,
+    w_amp,
+    bytes_read / kMB / elapsed,
+    stats.bytes_written / kMB / elapsed,
+    stats.files_in_leveln,
+    stats.files_in_levelnp1,
+    stats.files_out_levelnp1,
+    stats.files_out_levelnp1 - stats.files_in_levelnp1,
+    stats.micros / 1000000.0,
+    stats.count,
+    stats.count == 0 ? 0 : stats.micros / 1000000.0 / stats.count,
+    stall_us / 1000000.0,
+    stalls,
+    stalls == 0 ? 0 : stall_us / 1000.0 / stalls);
+}
+
+
+}
+
+DBPropertyType GetPropertyType(const Slice& property, bool* is_int_property,
+                               bool* need_out_of_mutex) {
+  assert(is_int_property != nullptr);
+  assert(need_out_of_mutex != nullptr);
  Slice in = property;
  Slice prefix("rocksdb.");
-  if (!in.starts_with(prefix)) return kUnknown;
+  *need_out_of_mutex = false;
+  *is_int_property = false;
+  if (!in.starts_with(prefix)) {
+    return kUnknown;
+  }
  in.remove_prefix(prefix.size());

  if (in.starts_with("num-files-at-level")) {
@@ -25,9 +105,16 @@ DBPropertyType GetPropertyType(const Slice& property) {
    return kLevelStats;
  } else if (in == "stats") {
    return kStats;
+  } else if (in == "cfstats") {
+    return kCFStats;
+  } else if (in == "dbstats") {
+    return kDBStats;
  } else if (in == "sstables") {
    return kSsTables;
-  } else if (in == "num-immutable-mem-table") {
+  }
+
+  *is_int_property = true;
+  if (in == "num-immutable-mem-table") {
    return kNumImmutableMemTable;
  } else if (in == "mem-table-flush-pending") {
    return kMemtableFlushPending;
@@ -41,14 +128,35 @@ DBPropertyType GetPropertyType(const Slice& property) {
    return kNumEntriesInMutableMemtable;
  } else if (in == "num-entries-imm-mem-tables") {
    return kNumEntriesInImmutableMemtable;
+  } else if (in == "estimate-num-keys") {
+    return kEstimatedNumKeys;
+  } else if (in == "estimate-table-readers-mem") {
+    *need_out_of_mutex = true;
+    return kEstimatedUsageByTableReaders;
  }
  return kUnknown;
 }

-bool InternalStats::GetProperty(DBPropertyType property_type,
-                                const Slice& property, std::string* value,
-                                ColumnFamilyData* cfd) {
-  Version* current = cfd->current();
+bool InternalStats::GetIntPropertyOutOfMutex(DBPropertyType property_type,
+                                             Version* version,
+                                             uint64_t* value) const {
+  assert(value != nullptr);
+  if (property_type != kEstimatedUsageByTableReaders) {
+    return false;
+  }
+  if (version == nullptr) {
+    *value = 0;
+  } else {
+    *value = version->GetMemoryUsageByTableReaders();
+  }
+  return true;
+}
+
+bool InternalStats::GetStringProperty(DBPropertyType property_type,
+                                      const Slice& property,
+                                      std::string* value) {
+  assert(value != nullptr);
+  Version* current = cfd_->current();
  Slice in = property;

  switch (property_type) {
@@ -76,294 +184,287 @@ bool InternalStats::GetProperty(DBPropertyType property_type,
      for (int level = 0; level < number_levels_; level++) {
        snprintf(buf, sizeof(buf), "%3d %8d %8.0f\n", level,
                 current->NumLevelFiles(level),
-                 current->NumLevelBytes(level) / 1048576.0);
+                 current->NumLevelBytes(level) / kMB);
        value->append(buf);
      }
      return true;
    }
    case kStats: {
-      char buf[1000];
-
-      uint64_t wal_bytes = 0;
-      uint64_t wal_synced = 0;
-      uint64_t user_bytes_written = 0;
-      uint64_t write_other = 0;
-      uint64_t write_self = 0;
-      uint64_t write_with_wal = 0;
-      uint64_t total_bytes_written = 0;
-      uint64_t total_bytes_read = 0;
-      uint64_t micros_up = env_->NowMicros() - started_at_;
-      // Add "+1" to make sure seconds_up is > 0 and avoid NaN later
-      double seconds_up = (micros_up + 1) / 1000000.0;
-      uint64_t total_slowdown = 0;
-      uint64_t total_slowdown_count = 0;
-      uint64_t interval_bytes_written = 0;
-      uint64_t interval_bytes_read = 0;
-      uint64_t interval_bytes_new = 0;
-      double interval_seconds_up = 0;
-
-      if (statistics_) {
-        wal_bytes = statistics_->getTickerCount(WAL_FILE_BYTES);
-        wal_synced = statistics_->getTickerCount(WAL_FILE_SYNCED);
-        user_bytes_written = statistics_->getTickerCount(BYTES_WRITTEN);
-        write_other = statistics_->getTickerCount(WRITE_DONE_BY_OTHER);
-        write_self = statistics_->getTickerCount(WRITE_DONE_BY_SELF);
-        write_with_wal = statistics_->getTickerCount(WRITE_WITH_WAL);
+      if (!GetStringProperty(kCFStats, "rocksdb.cfstats", value)) {
+        return false;
      }
-
-      snprintf(
-          buf, sizeof(buf),
-          "                               Compactions\n"
-          "Level  Files Size(MB) Score Time(sec)  Read(MB) Write(MB)    Rn(MB) "
-          " "
-          "Rnp1(MB)  Wnew(MB) RW-Amplify Read(MB/s) Write(MB/s)      Rn     "
-          "Rnp1 "
-          "    Wnp1     NewW    Count   msComp   msStall  Ln-stall Stall-cnt\n"
-          "--------------------------------------------------------------------"
-          "--"
-          "--------------------------------------------------------------------"
-          "--"
-          "----------------------------------------------------------------\n");
-      value->append(buf);
-      for (int level = 0; level < number_levels_; level++) {
-        int files = current->NumLevelFiles(level);
-        if (compaction_stats_[level].micros > 0 || files > 0) {
-          int64_t bytes_read = compaction_stats_[level].bytes_readn +
-                               compaction_stats_[level].bytes_readnp1;
-          int64_t bytes_new = compaction_stats_[level].bytes_written -
-                              compaction_stats_[level].bytes_readnp1;
-          double amplify =
-              (compaction_stats_[level].bytes_readn == 0)
-                  ? 0.0
-                  : (compaction_stats_[level].bytes_written +
-                     compaction_stats_[level].bytes_readnp1 +
-                     compaction_stats_[level].bytes_readn) /
-                        (double)compaction_stats_[level].bytes_readn;
-
-          total_bytes_read += bytes_read;
-          total_bytes_written += compaction_stats_[level].bytes_written;
-
-          uint64_t stalls = level == 0 ? (stall_counts_[LEVEL0_SLOWDOWN] +
-                                          stall_counts_[LEVEL0_NUM_FILES] +
-                                          stall_counts_[MEMTABLE_COMPACTION])
-                                       : stall_leveln_slowdown_count_[level];
-
-          double stall_us = level == 0 ? (stall_micros_[LEVEL0_SLOWDOWN] +
-                                          stall_micros_[LEVEL0_NUM_FILES] +
-                                          stall_micros_[MEMTABLE_COMPACTION])
-                                       : stall_leveln_slowdown_[level];
-
-          snprintf(buf, sizeof(buf),
-                   "%3d %8d %8.0f %5.1f %9.0f %9.0f %9.0f %9.0f %9.0f %9.0f "
-                   "%10.1f %9.1f %11.1f %8d %8d %8d %8d %8d %8d %9.1f %9.1f "
-                   "%9lu\n",
-                   level, files, current->NumLevelBytes(level) / 1048576.0,
-                   current->NumLevelBytes(level) /
-                       cfd->compaction_picker()->MaxBytesForLevel(level),
-                   compaction_stats_[level].micros / 1e6,
-                   bytes_read / 1048576.0,
-                   compaction_stats_[level].bytes_written / 1048576.0,
-                   compaction_stats_[level].bytes_readn / 1048576.0,
-                   compaction_stats_[level].bytes_readnp1 / 1048576.0,
-                   bytes_new / 1048576.0, amplify,
-                   // +1 to avoid division by 0
-                   (bytes_read / 1048576.0) /
-                       ((compaction_stats_[level].micros + 1) / 1000000.0),
-                   (compaction_stats_[level].bytes_written / 1048576.0) /
-                       ((compaction_stats_[level].micros + 1) / 1000000.0),
-                   compaction_stats_[level].files_in_leveln,
-                   compaction_stats_[level].files_in_levelnp1,
-                   compaction_stats_[level].files_out_levelnp1,
-                   compaction_stats_[level].files_out_levelnp1 -
-                       compaction_stats_[level].files_in_levelnp1,
-                   compaction_stats_[level].count,
-                   (int)((double)compaction_stats_[level].micros / 1000.0 /
-                         (compaction_stats_[level].count + 1)),
-                   (double)stall_us / 1000.0 / (stalls + 1),
-                   stall_us / 1000000.0, (unsigned long)stalls);
-          total_slowdown += stall_leveln_slowdown_[level];
-          total_slowdown_count += stall_leveln_slowdown_count_[level];
-          value->append(buf);
-        }
+      if (!GetStringProperty(kDBStats, "rocksdb.dbstats", value)) {
+        return false;
      }
-
-      interval_bytes_new = user_bytes_written - last_stats_.ingest_bytes_;
-      interval_bytes_read =
-          total_bytes_read - last_stats_.compaction_bytes_read_;
-      interval_bytes_written =
-          total_bytes_written - last_stats_.compaction_bytes_written_;
-      interval_seconds_up = seconds_up - last_stats_.seconds_up_;
-
-      snprintf(buf, sizeof(buf), "Uptime(secs): %.1f total, %.1f interval\n",
-               seconds_up, interval_seconds_up);
-      value->append(buf);
-
-      snprintf(buf, sizeof(buf),
-               "Writes cumulative: %llu total, %llu batches, "
-               "%.1f per batch, %.2f ingest GB\n",
-               (unsigned long long)(write_other + write_self),
-               (unsigned long long)write_self,
-               (write_other + write_self) / (double)(write_self + 1),
-               user_bytes_written / (1048576.0 * 1024));
-      value->append(buf);
-
-      snprintf(buf, sizeof(buf),
-               "WAL cumulative: %llu WAL writes, %llu WAL syncs, "
-               "%.2f writes per sync, %.2f GB written\n",
-               (unsigned long long)write_with_wal,
-               (unsigned long long)wal_synced,
-               write_with_wal / (double)(wal_synced + 1),
-               wal_bytes / (1048576.0 * 1024));
-      value->append(buf);
-
-      snprintf(buf, sizeof(buf),
-               "Compaction IO cumulative (GB): "
-               "%.2f new, %.2f read, %.2f write, %.2f read+write\n",
-               user_bytes_written / (1048576.0 * 1024),
-               total_bytes_read / (1048576.0 * 1024),
-               total_bytes_written / (1048576.0 * 1024),
-               (total_bytes_read + total_bytes_written) / (1048576.0 * 1024));
-      value->append(buf);
-
-      snprintf(
-          buf, sizeof(buf),
-          "Compaction IO cumulative (MB/sec): "
-          "%.1f new, %.1f read, %.1f write, %.1f read+write\n",
-          user_bytes_written / 1048576.0 / seconds_up,
-          total_bytes_read / 1048576.0 / seconds_up,
-          total_bytes_written / 1048576.0 / seconds_up,
-          (total_bytes_read + total_bytes_written) / 1048576.0 / seconds_up);
-      value->append(buf);
-
-      // +1 to avoid divide by 0 and NaN
-      snprintf(
-          buf, sizeof(buf),
-          "Amplification cumulative: %.1f write, %.1f compaction\n",
-          (double)(total_bytes_written + wal_bytes) / (user_bytes_written + 1),
-          (double)(total_bytes_written + total_bytes_read + wal_bytes) /
-              (user_bytes_written + 1));
-      value->append(buf);
-
-      uint64_t interval_write_other = write_other - last_stats_.write_other_;
-      uint64_t interval_write_self = write_self - last_stats_.write_self_;
-
-      snprintf(buf, sizeof(buf),
-               "Writes interval: %llu total, %llu batches, "
-               "%.1f per batch, %.1f ingest MB\n",
-               (unsigned long long)(interval_write_other + interval_write_self),
-               (unsigned long long)interval_write_self,
-               (double)(interval_write_other + interval_write_self) /
-                   (interval_write_self + 1),
-               (user_bytes_written - last_stats_.ingest_bytes_) / 1048576.0);
-      value->append(buf);
-
-      uint64_t interval_write_with_wal =
-          write_with_wal - last_stats_.write_with_wal_;
-
-      uint64_t interval_wal_synced = wal_synced - last_stats_.wal_synced_;
-      uint64_t interval_wal_bytes = wal_bytes - last_stats_.wal_bytes_;
-
-      snprintf(buf, sizeof(buf),
-               "WAL interval: %llu WAL writes, %llu WAL syncs, "
-               "%.2f writes per sync, %.2f MB written\n",
-               (unsigned long long)interval_write_with_wal,
-               (unsigned long long)interval_wal_synced,
-               interval_write_with_wal / (double)(interval_wal_synced + 1),
-               interval_wal_bytes / (1048576.0 * 1024));
-      value->append(buf);
-
-      snprintf(buf, sizeof(buf),
-               "Compaction IO interval (MB): "
-               "%.2f new, %.2f read, %.2f write, %.2f read+write\n",
-               interval_bytes_new / 1048576.0, interval_bytes_read / 1048576.0,
-               interval_bytes_written / 1048576.0,
-               (interval_bytes_read + interval_bytes_written) / 1048576.0);
-      value->append(buf);
-
-      snprintf(buf, sizeof(buf),
-               "Compaction IO interval (MB/sec): "
-               "%.1f new, %.1f read, %.1f write, %.1f read+write\n",
-               interval_bytes_new / 1048576.0 / interval_seconds_up,
-               interval_bytes_read / 1048576.0 / interval_seconds_up,
-               interval_bytes_written / 1048576.0 / interval_seconds_up,
-               (interval_bytes_read + interval_bytes_written) / 1048576.0 /
-                   interval_seconds_up);
-      value->append(buf);
-
-      // +1 to avoid divide by 0 and NaN
-      snprintf(
-          buf, sizeof(buf),
-          "Amplification interval: %.1f write, %.1f compaction\n",
-          (double)(interval_bytes_written + wal_bytes) /
-              (interval_bytes_new + 1),
-          (double)(interval_bytes_written + interval_bytes_read + wal_bytes) /
-              (interval_bytes_new + 1));
-      value->append(buf);
-
-      snprintf(buf, sizeof(buf),
-               "Stalls(secs): %.3f level0_slowdown, %.3f level0_numfiles, "
-               "%.3f memtable_compaction, %.3f leveln_slowdown\n",
-               stall_micros_[LEVEL0_SLOWDOWN] / 1000000.0,
-               stall_micros_[LEVEL0_NUM_FILES] / 1000000.0,
-               stall_micros_[MEMTABLE_COMPACTION] / 1000000.0,
-               total_slowdown / 1000000.0);
-      value->append(buf);
-
-      snprintf(buf, sizeof(buf),
-               "Stalls(count): %lu level0_slowdown, %lu level0_numfiles, "
-               "%lu memtable_compaction, %lu leveln_slowdown\n",
-               (unsigned long)stall_counts_[LEVEL0_SLOWDOWN],
-               (unsigned long)stall_counts_[LEVEL0_NUM_FILES],
-               (unsigned long)stall_counts_[MEMTABLE_COMPACTION],
-               (unsigned long)total_slowdown_count);
-      value->append(buf);
-
-      last_stats_.compaction_bytes_read_ = total_bytes_read;
-      last_stats_.compaction_bytes_written_ = total_bytes_written;
-      last_stats_.ingest_bytes_ = user_bytes_written;
-      last_stats_.seconds_up_ = seconds_up;
-      last_stats_.wal_bytes_ = wal_bytes;
-      last_stats_.wal_synced_ = wal_synced;
-      last_stats_.write_with_wal_ = write_with_wal;
-      last_stats_.write_other_ = write_other;
-      last_stats_.write_self_ = write_self;
-
+      return true;
+    }
+    case kCFStats: {
+      DumpCFStats(value);
+      return true;
+    }
+    case kDBStats: {
+      DumpDBStats(value);
      return true;
    }
    case kSsTables:
      *value = current->DebugString();
      return true;
-    case kNumImmutableMemTable:
-      *value = std::to_string(cfd->imm()->size());
-      return true;
-    case kMemtableFlushPending:
-      // Return number of mem tables that are ready to flush (made immutable)
-      *value = std::to_string(cfd->imm()->IsFlushPending() ? 1 : 0);
-      return true;
-    case kCompactionPending:
-      // 1 if the system already determines at least one compacdtion is needed.
-      // 0 otherwise,
-      *value = std::to_string(current->NeedsCompaction() ? 1 : 0);
-      return true;
-    case kBackgroundErrors:
-      // Accumulated number of  errors in background flushes or compactions.
-      *value = std::to_string(GetBackgroundErrorCount());
-      return true;
-    case kCurSizeActiveMemTable:
-      // Current size of the active memtable
-      *value = std::to_string(cfd->mem()->ApproximateMemoryUsage());
-      return true;
-    case kNumEntriesInMutableMemtable:
-      // Current size of the active memtable
-      *value = std::to_string(cfd->mem()->GetNumEntries());
-      return true;
-    case kNumEntriesInImmutableMemtable:
-      // Current size of the active memtable
-      *value = std::to_string(cfd->imm()->current()->GetTotalNumEntries());
-      return true;
    default:
      return false;
  }
 }

+bool InternalStats::GetIntProperty(DBPropertyType property_type,
+                                   uint64_t* value) const {
+  Version* current = cfd_->current();
+
+  switch (property_type) {
+    case kNumImmutableMemTable:
+      *value = cfd_->imm()->size();
+      return true;
+    case kMemtableFlushPending:
+      // Return number of mem tables that are ready to flush (made immutable)
+      *value = (cfd_->imm()->IsFlushPending() ? 1 : 0);
+      return true;
+    case kCompactionPending:
+      // 1 if the system already determines at least one compacdtion is needed.
+      // 0 otherwise,
+      *value = (current->NeedsCompaction() ? 1 : 0);
+      return true;
+    case kBackgroundErrors:
+      // Accumulated number of  errors in background flushes or compactions.
+      *value = GetBackgroundErrorCount();
+      return true;
+    case kCurSizeActiveMemTable:
+      // Current size of the active memtable
+      *value = cfd_->mem()->ApproximateMemoryUsage();
+      return true;
+    case kNumEntriesInMutableMemtable:
+      // Current size of the active memtable
+      *value = cfd_->mem()->GetNumEntries();
+      return true;
+    case kNumEntriesInImmutableMemtable:
+      // Current size of the active memtable
+      *value = cfd_->imm()->current()->GetTotalNumEntries();
+      return true;
+    case kEstimatedNumKeys:
+      // Estimate number of entries in the column family:
+      // Use estimated entries in tables + total entries in memtables.
+      *value = cfd_->mem()->GetNumEntries() +
+               cfd_->imm()->current()->GetTotalNumEntries() +
+               current->GetEstimatedActiveKeys();
+      return true;
+    default:
+      return false;
+  }
+}
+
+void InternalStats::DumpDBStats(std::string* value) {
+  char buf[1000];
+  // DB-level stats, only available from default column family
+  double seconds_up = (env_->NowMicros() - started_at_ + 1) / 1000000.0;
+  double interval_seconds_up = seconds_up - db_stats_snapshot_.seconds_up;
+  snprintf(buf, sizeof(buf),
+           "\n** DB Stats **\nUptime(secs): %.1f total, %.1f interval\n",
+           seconds_up, interval_seconds_up);
+  value->append(buf);
+  // Cumulative
+  uint64_t user_bytes_written = db_stats_[InternalStats::BYTES_WRITTEN];
+  uint64_t write_other = db_stats_[InternalStats::WRITE_DONE_BY_OTHER];
+  uint64_t write_self = db_stats_[InternalStats::WRITE_DONE_BY_SELF];
+  uint64_t wal_bytes = db_stats_[InternalStats::WAL_FILE_BYTES];
+  uint64_t wal_synced = db_stats_[InternalStats::WAL_FILE_SYNCED];
+  uint64_t write_with_wal = db_stats_[InternalStats::WRITE_WITH_WAL];
+  // Data
+  snprintf(buf, sizeof(buf),
+           "Cumulative writes: %" PRIu64 " writes, %" PRIu64 " batches, "
+           "%.1f writes per batch, %.2f GB user ingest\n",
+           write_other + write_self, write_self,
+           (write_other + write_self) / static_cast<double>(write_self + 1),
+           user_bytes_written / kGB);
+  value->append(buf);
+  // WAL
+  snprintf(buf, sizeof(buf),
+           "Cumulative WAL: %" PRIu64 " writes, %" PRIu64 " syncs, "
+           "%.2f writes per sync, %.2f GB written\n",
+           write_with_wal, wal_synced,
+           write_with_wal / static_cast<double>(wal_synced + 1),
+           wal_bytes / kGB);
+  value->append(buf);
+
+  // Interval
+  uint64_t interval_write_other = write_other - db_stats_snapshot_.write_other;
+  uint64_t interval_write_self = write_self - db_stats_snapshot_.write_self;
+  snprintf(buf, sizeof(buf),
+           "Interval writes: %" PRIu64 " writes, %" PRIu64 " batches, "
+           "%.1f writes per batch, %.1f MB user ingest\n",
+           interval_write_other + interval_write_self,
+           interval_write_self,
+           static_cast<double>(interval_write_other + interval_write_self) /
+               (interval_write_self + 1),
+           (user_bytes_written - db_stats_snapshot_.ingest_bytes) / kMB);
+  value->append(buf);
+
+  uint64_t interval_write_with_wal =
+      write_with_wal - db_stats_snapshot_.write_with_wal;
+  uint64_t interval_wal_synced = wal_synced - db_stats_snapshot_.wal_synced;
+  uint64_t interval_wal_bytes = wal_bytes - db_stats_snapshot_.wal_bytes;
+
+  snprintf(buf, sizeof(buf),
+           "Interval WAL: %" PRIu64 " writes, %" PRIu64 " syncs, "
+           "%.2f writes per sync, %.2f MB written\n",
+           interval_write_with_wal,
+           interval_wal_synced,
+           interval_write_with_wal /
+              static_cast<double>(interval_wal_synced + 1),
+           interval_wal_bytes / kGB);
+  value->append(buf);
+
+  db_stats_snapshot_.seconds_up = seconds_up;
+  db_stats_snapshot_.ingest_bytes = user_bytes_written;
+  db_stats_snapshot_.write_other = write_other;
+  db_stats_snapshot_.write_self = write_self;
+  db_stats_snapshot_.wal_bytes = wal_bytes;
+  db_stats_snapshot_.wal_synced = wal_synced;
+  db_stats_snapshot_.write_with_wal = write_with_wal;
+}
+
+void InternalStats::DumpCFStats(std::string* value) {
+  Version* current = cfd_->current();
+
+  int num_levels_to_check =
+      (cfd_->options()->compaction_style != kCompactionStyleUniversal &&
+       cfd_->options()->compaction_style != kCompactionStyleFIFO)
+          ? current->NumberLevels() - 1
+          : 1;
+  // Compaction scores are sorted base on its value. Restore them to the
+  // level order
+  std::vector<double> compaction_score(number_levels_, 0);
+  for (int i = 0; i < num_levels_to_check; ++i) {
+    compaction_score[current->compaction_level_[i]] =
+      current->compaction_score_[i];
+  }
+  // Count # of files being compacted for each level
+  std::vector<int> files_being_compacted(number_levels_, 0);
+  for (int level = 0; level < num_levels_to_check; ++level) {
+    for (auto* f : current->files_[level]) {
+      if (f->being_compacted) {
+        ++files_being_compacted[level];
+      }
+    }
+  }
+
+  char buf[1000];
+  // Per-ColumnFamily stats
+  PrintLevelStatsHeader(buf, sizeof(buf), cfd_->GetName());
+  value->append(buf);
+
+  CompactionStats stats_sum(0);
+  int total_files = 0;
+  int total_files_being_compacted = 0;
+  double total_file_size = 0;
+  uint64_t total_slowdown_soft = 0;
+  uint64_t total_slowdown_count_soft = 0;
+  uint64_t total_slowdown_hard = 0;
+  uint64_t total_slowdown_count_hard = 0;
+  uint64_t total_stall_count = 0;
+  double total_stall_us = 0;
+  for (int level = 0; level < number_levels_; level++) {
+    int files = current->NumLevelFiles(level);
+    total_files += files;
+    total_files_being_compacted += files_being_compacted[level];
+    if (comp_stats_[level].micros > 0 || files > 0) {
+      uint64_t stalls = level == 0 ?
+        (cf_stats_count_[LEVEL0_SLOWDOWN] +
+         cf_stats_count_[LEVEL0_NUM_FILES] +
+         cf_stats_count_[MEMTABLE_COMPACTION])
+        : (stall_leveln_slowdown_count_soft_[level] +
+           stall_leveln_slowdown_count_hard_[level]);
+
+      double stall_us = level == 0 ?
+         (cf_stats_value_[LEVEL0_SLOWDOWN] +
+          cf_stats_value_[LEVEL0_NUM_FILES] +
+          cf_stats_value_[MEMTABLE_COMPACTION])
+         : (stall_leveln_slowdown_soft_[level] +
+            stall_leveln_slowdown_hard_[level]);
+
+      stats_sum.Add(comp_stats_[level]);
+      total_file_size += current->NumLevelBytes(level);
+      total_stall_us += stall_us;
+      total_stall_count += stalls;
+      total_slowdown_soft += stall_leveln_slowdown_soft_[level];
+      total_slowdown_count_soft += stall_leveln_slowdown_count_soft_[level];
+      total_slowdown_hard += stall_leveln_slowdown_hard_[level];
+      total_slowdown_count_hard += stall_leveln_slowdown_count_hard_[level];
+      int64_t bytes_read = comp_stats_[level].bytes_readn +
+                           comp_stats_[level].bytes_readnp1;
+      double rw_amp = (comp_stats_[level].bytes_readn == 0) ? 0.0
+          : (comp_stats_[level].bytes_written + bytes_read) /
+            static_cast<double>(comp_stats_[level].bytes_readn);
+      double w_amp = (comp_stats_[level].bytes_readn == 0) ? 0.0
+          : comp_stats_[level].bytes_written /
+            static_cast<double>(comp_stats_[level].bytes_readn);
+      PrintLevelStats(buf, sizeof(buf), "L" + std::to_string(level),
+          files, files_being_compacted[level], current->NumLevelBytes(level),
+          compaction_score[level], rw_amp, w_amp, stall_us, stalls,
+          comp_stats_[level]);
+      value->append(buf);
+    }
+  }
+  uint64_t curr_ingest = cf_stats_value_[BYTES_FLUSHED];
+  // Cumulative summary
+  double rw_amp = (stats_sum.bytes_written + stats_sum.bytes_readn +
+      stats_sum.bytes_readnp1) / static_cast<double>(curr_ingest + 1);
+  double w_amp = stats_sum.bytes_written / static_cast<double>(curr_ingest + 1);
+  // Stats summary across levels
+  PrintLevelStats(buf, sizeof(buf), "Sum", total_files,
+      total_files_being_compacted, total_file_size, 0, rw_amp, w_amp,
+      total_stall_us, total_stall_count, stats_sum);
+  value->append(buf);
+  // Interval summary
+  uint64_t interval_ingest =
+      curr_ingest - cf_stats_snapshot_.ingest_bytes + 1;
+  CompactionStats interval_stats(stats_sum);
+  interval_stats.Subtract(cf_stats_snapshot_.comp_stats);
+  rw_amp = (interval_stats.bytes_written +
+      interval_stats.bytes_readn + interval_stats.bytes_readnp1) /
+      static_cast<double>(interval_ingest);
+  w_amp = interval_stats.bytes_written / static_cast<double>(interval_ingest);
+  PrintLevelStats(buf, sizeof(buf), "Int", 0, 0, 0, 0,
+      rw_amp, w_amp, total_stall_us - cf_stats_snapshot_.stall_us,
+      total_stall_count - cf_stats_snapshot_.stall_count, interval_stats);
+  value->append(buf);
+
+  snprintf(buf, sizeof(buf),
+           "Flush(GB): accumulative %.3f, interval %.3f\n",
+           curr_ingest / kGB, interval_ingest / kGB);
+  value->append(buf);
+  snprintf(buf, sizeof(buf),
+           "Stalls(secs): %.3f level0_slowdown, %.3f level0_numfiles, "
+           "%.3f memtable_compaction, %.3f leveln_slowdown_soft, "
+           "%.3f leveln_slowdown_hard\n",
+           cf_stats_value_[LEVEL0_SLOWDOWN] / 1000000.0,
+           cf_stats_value_[LEVEL0_NUM_FILES] / 1000000.0,
+           cf_stats_value_[MEMTABLE_COMPACTION] / 1000000.0,
+           total_slowdown_soft / 1000000.0,
+           total_slowdown_hard / 1000000.0);
+  value->append(buf);
+
+  snprintf(buf, sizeof(buf),
+           "Stalls(count): %" PRIu64 " level0_slowdown, "
+           "%" PRIu64 " level0_numfiles, %" PRIu64 " memtable_compaction, "
+           "%" PRIu64 " leveln_slowdown_soft, "
+           "%" PRIu64 " leveln_slowdown_hard\n",
+           cf_stats_count_[LEVEL0_SLOWDOWN],
+           cf_stats_count_[LEVEL0_NUM_FILES],
+           cf_stats_count_[MEMTABLE_COMPACTION],
+           total_slowdown_count_soft, total_slowdown_count_hard);
+  value->append(buf);
+
+  cf_stats_snapshot_.ingest_bytes = curr_ingest;
+  cf_stats_snapshot_.comp_stats = stats_sum;
+  cf_stats_snapshot_.stall_us = total_stall_us;
+  cf_stats_snapshot_.stall_count = total_stall_count;
+}
+
 }  // namespace rocksdb
@@ -9,8 +9,6 @@
 //

 #pragma once
-#include "rocksdb/statistics.h"
-#include "util/statistics.h"
 #include "db/version_set.h"

 #include <vector>
@@ -23,11 +21,15 @@ namespace rocksdb {
 class MemTableList;
 class DBImpl;

-enum DBPropertyType {
+enum DBPropertyType : uint32_t {
+  kUnknown,
  kNumFilesAtLevel,  // Number of files at a specific level
  kLevelStats,       // Return number of files and total sizes of each level
-  kStats,            // Return general statitistics of DB
+  kCFStats,          // Return general statitistics of CF
+  kDBStats,          // Return general statitistics of DB
+  kStats,            // Return general statitistics of both DB and CF
  kSsTables,         // Return a human readable string of current SST files
+  kStartIntTypes,    // ---- Dummy value to indicate the start of integer values
  kNumImmutableMemTable,   // Return number of immutable mem tables
  kMemtableFlushPending,   // Return 1 if mem table flushing is pending,
                           // otherwise 0.
@@ -38,45 +40,77 @@ enum DBPropertyType {
                                   // memtable.
  kNumEntriesInImmutableMemtable,  // Return sum of number of entries in all
                                   // the immutable mem tables.
-  kUnknown,
+  kEstimatedNumKeys,  // Estimated total number of keys in the database.
+  kEstimatedUsageByTableReaders,  // Estimated memory by table readers.
 };

-extern DBPropertyType GetPropertyType(const Slice& property);
+extern DBPropertyType GetPropertyType(const Slice& property,
+                                      bool* is_int_property,
+                                      bool* need_out_of_mutex);

 class InternalStats {
 public:
-  enum WriteStallType {
+  enum InternalCFStatsType {
    LEVEL0_SLOWDOWN,
    MEMTABLE_COMPACTION,
    LEVEL0_NUM_FILES,
    WRITE_STALLS_ENUM_MAX,
+    BYTES_FLUSHED,
+    INTERNAL_CF_STATS_ENUM_MAX,
  };

-  InternalStats(int num_levels, Env* env, Statistics* statistics)
-      : compaction_stats_(num_levels),
-        stall_micros_(WRITE_STALLS_ENUM_MAX, 0),
-        stall_counts_(WRITE_STALLS_ENUM_MAX, 0),
-        stall_leveln_slowdown_(num_levels, 0),
-        stall_leveln_slowdown_count_(num_levels, 0),
+  enum InternalDBStatsType {
+    WAL_FILE_BYTES,
+    WAL_FILE_SYNCED,
+    BYTES_WRITTEN,
+    WRITE_DONE_BY_OTHER,
+    WRITE_DONE_BY_SELF,
+    WRITE_WITH_WAL,
+    INTERNAL_DB_STATS_ENUM_MAX,
+  };
+
+  InternalStats(int num_levels, Env* env, ColumnFamilyData* cfd)
+      : db_stats_(INTERNAL_DB_STATS_ENUM_MAX),
+        cf_stats_value_(INTERNAL_CF_STATS_ENUM_MAX),
+        cf_stats_count_(INTERNAL_CF_STATS_ENUM_MAX),
+        comp_stats_(num_levels),
+        stall_leveln_slowdown_hard_(num_levels),
+        stall_leveln_slowdown_count_hard_(num_levels),
+        stall_leveln_slowdown_soft_(num_levels),
+        stall_leveln_slowdown_count_soft_(num_levels),
        bg_error_count_(0),
        number_levels_(num_levels),
-        statistics_(statistics),
        env_(env),
-        started_at_(env->NowMicros()) {}
+        cfd_(cfd),
+        started_at_(env->NowMicros()) {
+    for (int i = 0; i< INTERNAL_DB_STATS_ENUM_MAX; ++i) {
+      db_stats_[i] = 0;
+    }
+    for (int i = 0; i< INTERNAL_CF_STATS_ENUM_MAX; ++i) {
+      cf_stats_value_[i] = 0;
+      cf_stats_count_[i] = 0;
+    }
+    for (int i = 0; i < num_levels; ++i) {
+      stall_leveln_slowdown_hard_[i] = 0;
+      stall_leveln_slowdown_count_hard_[i] = 0;
+      stall_leveln_slowdown_soft_[i] = 0;
+      stall_leveln_slowdown_count_soft_[i] = 0;
+    }
+  }

-  // Per level compaction stats.  compaction_stats_[level] stores the stats for
+  // Per level compaction stats.  comp_stats_[level] stores the stats for
  // compactions that produced data for the specified "level".
  struct CompactionStats {
    uint64_t micros;

    // Bytes read from level N during compaction between levels N and N+1
-    int64_t bytes_readn;
+    uint64_t bytes_readn;

    // Bytes read from level N+1 during compaction between levels N and N+1
-    int64_t bytes_readnp1;
+    uint64_t bytes_readnp1;

    // Total bytes written during compaction between levels N and N+1
-    int64_t bytes_written;
+    uint64_t bytes_written;

    // Files read from level N during compaction between levels N and N+1
    int files_in_leveln;
@@ -90,7 +124,7 @@ class InternalStats {
    // Number of compactions done
    int count;

-    CompactionStats()
+    explicit CompactionStats(int count = 0)
        : micros(0),
          bytes_readn(0),
          bytes_readnp1(0),
@@ -98,7 +132,17 @@ class InternalStats {
          files_in_leveln(0),
          files_in_levelnp1(0),
          files_out_levelnp1(0),
-          count(0) {}
+          count(count) {}
+
+    explicit CompactionStats(const CompactionStats& c)
+        : micros(c.micros),
+          bytes_readn(c.bytes_readn),
+          bytes_readnp1(c.bytes_readnp1),
+          bytes_written(c.bytes_written),
+          files_in_leveln(c.files_in_leveln),
+          files_in_levelnp1(c.files_in_levelnp1),
+          files_out_levelnp1(c.files_out_levelnp1),
+          count(c.count) {}

    void Add(const CompactionStats& c) {
      this->micros += c.micros;
@@ -108,68 +152,109 @@ class InternalStats {
      this->files_in_leveln += c.files_in_leveln;
      this->files_in_levelnp1 += c.files_in_levelnp1;
      this->files_out_levelnp1 += c.files_out_levelnp1;
-      this->count += 1;
+      this->count += c.count;
+    }
+
+    void Subtract(const CompactionStats& c) {
+      this->micros -= c.micros;
+      this->bytes_readn -= c.bytes_readn;
+      this->bytes_readnp1 -= c.bytes_readnp1;
+      this->bytes_written -= c.bytes_written;
+      this->files_in_leveln -= c.files_in_leveln;
+      this->files_in_levelnp1 -= c.files_in_levelnp1;
+      this->files_out_levelnp1 -= c.files_out_levelnp1;
+      this->count -= c.count;
    }
  };

  void AddCompactionStats(int level, const CompactionStats& stats) {
-    compaction_stats_[level].Add(stats);
+    comp_stats_[level].Add(stats);
  }

-  void RecordWriteStall(WriteStallType write_stall_type, uint64_t micros) {
-    stall_micros_[write_stall_type] += micros;
-    stall_counts_[write_stall_type]++;
+  void RecordLevelNSlowdown(int level, uint64_t micros, bool soft) {
+    if (soft) {
+      stall_leveln_slowdown_soft_[level] += micros;
+      ++stall_leveln_slowdown_count_soft_[level];
+    } else {
+      stall_leveln_slowdown_hard_[level] += micros;
+      ++stall_leveln_slowdown_count_hard_[level];
+    }
  }

-  void RecordLevelNSlowdown(int level, uint64_t micros) {
-    stall_leveln_slowdown_[level] += micros;
-    stall_leveln_slowdown_count_[level] += micros;
+  void AddCFStats(InternalCFStatsType type, uint64_t value) {
+    cf_stats_value_[type] += value;
+    ++cf_stats_count_[type];
+  }
+
+  void AddDBStats(InternalDBStatsType type, uint64_t value) {
+    db_stats_[type] += value;
  }

  uint64_t GetBackgroundErrorCount() const { return bg_error_count_; }

  uint64_t BumpAndGetBackgroundErrorCount() { return ++bg_error_count_; }

-  bool GetProperty(DBPropertyType property_type, const Slice& property,
-                   std::string* value, ColumnFamilyData* cfd);
+  bool GetStringProperty(DBPropertyType property_type, const Slice& property,
+                         std::string* value);
+
+  bool GetIntProperty(DBPropertyType property_type, uint64_t* value) const;
+
+  bool GetIntPropertyOutOfMutex(DBPropertyType property_type, Version* version,
+                                uint64_t* value) const;

 private:
-  std::vector<CompactionStats> compaction_stats_;
+  void DumpDBStats(std::string* value);
+  void DumpCFStats(std::string* value);
+
+  // Per-DB stats
+  std::vector<uint64_t> db_stats_;
+  // Per-ColumnFamily stats
+  std::vector<uint64_t> cf_stats_value_;
+  std::vector<uint64_t> cf_stats_count_;
+  // Per-ColumnFamily/level compaction stats
+  std::vector<CompactionStats> comp_stats_;
+  // These count the number of microseconds for which MakeRoomForWrite stalls.
+  std::vector<uint64_t> stall_leveln_slowdown_hard_;
+  std::vector<uint64_t> stall_leveln_slowdown_count_hard_;
+  std::vector<uint64_t> stall_leveln_slowdown_soft_;
+  std::vector<uint64_t> stall_leveln_slowdown_count_soft_;

  // Used to compute per-interval statistics
-  struct StatsSnapshot {
-    uint64_t compaction_bytes_read_;     // Bytes read by compaction
-    uint64_t compaction_bytes_written_;  // Bytes written by compaction
-    uint64_t ingest_bytes_;              // Bytes written by user
-    uint64_t wal_bytes_;                 // Bytes written to WAL
-    uint64_t wal_synced_;                // Number of times WAL is synced
-    uint64_t write_with_wal_;            // Number of writes that request WAL
+  struct CFStatsSnapshot {
+    // ColumnFamily-level stats
+    CompactionStats comp_stats;
+    uint64_t ingest_bytes;            // Bytes written to L0
+    uint64_t stall_us;                // Stall time in micro-seconds
+    uint64_t stall_count;             // Stall count
+
+    CFStatsSnapshot()
+        : comp_stats(0),
+          ingest_bytes(0),
+          stall_us(0),
+          stall_count(0) {}
+  } cf_stats_snapshot_;
+
+  struct DBStatsSnapshot {
+    // DB-level stats
+    uint64_t ingest_bytes;            // Bytes written by user
+    uint64_t wal_bytes;               // Bytes written to WAL
+    uint64_t wal_synced;              // Number of times WAL is synced
+    uint64_t write_with_wal;          // Number of writes that request WAL
    // These count the number of writes processed by the calling thread or
    // another thread.
-    uint64_t write_other_;
-    uint64_t write_self_;
-    double seconds_up_;
+    uint64_t write_other;
+    uint64_t write_self;
+    double seconds_up;

-    StatsSnapshot()
-        : compaction_bytes_read_(0),
-          compaction_bytes_written_(0),
-          ingest_bytes_(0),
-          wal_bytes_(0),
-          wal_synced_(0),
-          write_with_wal_(0),
-          write_other_(0),
-          write_self_(0),
-          seconds_up_(0) {}
-  };
-
-  // Counters from the previous time per-interval stats were computed
-  StatsSnapshot last_stats_;
-
-  // These count the number of microseconds for which MakeRoomForWrite stalls.
-  std::vector<uint64_t> stall_micros_;
-  std::vector<uint64_t> stall_counts_;
-  std::vector<uint64_t> stall_leveln_slowdown_;
-  std::vector<uint64_t> stall_leveln_slowdown_count_;
+    DBStatsSnapshot()
+        : ingest_bytes(0),
+          wal_bytes(0),
+          wal_synced(0),
+          write_with_wal(0),
+          write_other(0),
+          write_self(0),
+          seconds_up(0) {}
+  } db_stats_snapshot_;

  // Total number of background errors encountered. Every time a flush task
  // or compaction task fails, this counter is incremented. The failure can
@@ -178,10 +263,10 @@ class InternalStats {
  // or compaction will cause the counter to increase too.
  uint64_t bg_error_count_;

-  int number_levels_;
-  Statistics* statistics_;
+  const int number_levels_;
  Env* env_;
-  uint64_t started_at_;
+  ColumnFamilyData* cfd_;
+  const uint64_t started_at_;
 };

 }  // namespace rocksdb
@@ -42,6 +42,11 @@ void BM_LogAndApply(int iters, int num_base_files) {

    Options options;
    EnvOptions sopt;
+    // Notice we are using the default options not through SanitizeOptions().
+    // We might want to initialize some options manually if needed.
+    options.db_paths.emplace_back(dbname, 0);
+    // The parameter of table cache is passed in as null, so any file I/O
+    // operation is likely to fail.
    vset = new VersionSet(dbname, &options, sopt, nullptr);
    std::vector<ColumnFamilyDescriptor> dummy;
    dummy.push_back(ColumnFamilyDescriptor());
@@ -51,7 +56,7 @@ void BM_LogAndApply(int iters, int num_base_files) {
    for (int i = 0; i < num_base_files; i++) {
      InternalKey start(MakeKey(2 * fnum), 1, kTypeValue);
      InternalKey limit(MakeKey(2 * fnum + 1), 1, kTypeDeletion);
-      vbase.AddFile(2, ++fnum, 1 /* file size */, start, limit, 1, 1);
+      vbase.AddFile(2, ++fnum, 0, 1 /* file size */, start, limit, 1, 1);
    }
    ASSERT_OK(vset->LogAndApply(default_cfd, &vbase, &mu));
  }
@@ -61,7 +66,7 @@ void BM_LogAndApply(int iters, int num_base_files) {
    vedit.DeleteFile(2, fnum);
    InternalKey start(MakeKey(2 * fnum), 1, kTypeValue);
    InternalKey limit(MakeKey(2 * fnum + 1), 1, kTypeDeletion);
-    vedit.AddFile(2, ++fnum, 1 /* file size */, start, limit, 1, 1);
+    vedit.AddFile(2, ++fnum, 0, 1 /* file size */, start, limit, 1, 1);
    vset->LogAndApply(default_cfd, &vedit, &mu);
  }
 }
@@ -20,6 +20,7 @@
 #include "rocksdb/iterator.h"
 #include "rocksdb/merge_operator.h"
 #include "rocksdb/slice_transform.h"
+#include "table/merger.h"
 #include "util/arena.h"
 #include "util/coding.h"
 #include "util/murmurhash.h"
@@ -37,7 +38,8 @@ MemTable::MemTable(const InternalKeyComparator& cmp, const Options& options)
      kWriteBufferSize(options.write_buffer_size),
      arena_(options.arena_block_size),
      table_(options.memtable_factory->CreateMemTableRep(
-          comparator_, &arena_, options.prefix_extractor.get())),
+          comparator_, &arena_, options.prefix_extractor.get(),
+          options.info_log.get())),
      num_entries_(0),
      flush_in_progress_(false),
      flush_completed_(false),
@@ -53,9 +55,11 @@ MemTable::MemTable(const InternalKeyComparator& cmp, const Options& options)
  assert(!should_flush_);
  if (prefix_extractor_ && options.memtable_prefix_bloom_bits > 0) {
    prefix_bloom_.reset(new DynamicBloom(
+        &arena_,
        options.memtable_prefix_bloom_bits, options.bloom_locality,
        options.memtable_prefix_bloom_probes, nullptr,
-        options.memtable_prefix_bloom_huge_page_tlb_size));
+        options.memtable_prefix_bloom_huge_page_tlb_size,
+        options.info_log.get()));
  }
 }

@@ -171,15 +175,24 @@ const char* EncodeKey(std::string* scratch, const Slice& target) {
 class MemTableIterator: public Iterator {
 public:
  MemTableIterator(const MemTable& mem, const ReadOptions& options,
-                   bool enforce_total_order)
+                   bool enforce_total_order, Arena* arena)
      : bloom_(nullptr),
        prefix_extractor_(mem.prefix_extractor_),
-        valid_(false) {
+        valid_(false),
+        arena_mode_(arena != nullptr) {
    if (prefix_extractor_ != nullptr && !enforce_total_order) {
      bloom_ = mem.prefix_bloom_.get();
-      iter_.reset(mem.table_->GetDynamicPrefixIterator());
+      iter_ = mem.table_->GetDynamicPrefixIterator(arena);
    } else {
-      iter_.reset(mem.table_->GetIterator());
+      iter_ = mem.table_->GetIterator(arena);
+    }
+  }
+
+  ~MemTableIterator() {
+    if (arena_mode_) {
+      iter_->~Iterator();
+    } else {
+      delete iter_;
    }
  }

@@ -226,8 +239,9 @@ class MemTableIterator: public Iterator {
 private:
  DynamicBloom* bloom_;
  const SliceTransform* const prefix_extractor_;
-  std::unique_ptr<MemTableRep::Iterator> iter_;
+  MemTableRep::Iterator* iter_;
  bool valid_;
+  bool arena_mode_;

  // No copying allowed
  MemTableIterator(const MemTableIterator&);
@@ -235,8 +249,14 @@ class MemTableIterator: public Iterator {
 };

 Iterator* MemTable::NewIterator(const ReadOptions& options,
-    bool enforce_total_order) {
-  return new MemTableIterator(*this, options, enforce_total_order);
+                                bool enforce_total_order, Arena* arena) {
+  if (arena == nullptr) {
+    return new MemTableIterator(*this, options, enforce_total_order, nullptr);
+  } else {
+    auto mem = arena->AllocateAligned(sizeof(MemTableIterator));
+    return new (mem)
+        MemTableIterator(*this, options, enforce_total_order, arena);
+  }
 }

 port::RWMutex* MemTable::GetLock(const Slice& key) {
@@ -347,7 +367,7 @@ static bool SaveValue(void* arg, const char* entry) {
          s->value->assign(v.data(), v.size());
        }
        if (s->inplace_update_support) {
-          s->mem->GetLock(s->key->user_key())->Unlock();
+          s->mem->GetLock(s->key->user_key())->ReadUnlock();
        }
        *(s->found_final_value) = true;
        return false;
@@ -370,6 +390,16 @@ static bool SaveValue(void* arg, const char* entry) {
        return false;
      }
      case kTypeMerge: {
+        if (!merge_operator) {
+          *(s->status) = Status::InvalidArgument(
+              "merge_operator is not properly initialized.");
+          // Normally we continue the loop (return true) when we see a merge
+          // operand.  But in case of an error, we should stop the loop
+          // immediately and pretend we have found the value to stop further
+          // seek.  Otherwise, the later call will override this error status.
+          *(s->found_final_value) = true;
+          return false;
+        }
        std::string merge_result;  // temporary area for merge results later
        Slice v = GetLengthPrefixedSlice(key_ptr + key_length);
        *(s->merge_in_progress) = true;
@@ -430,7 +460,7 @@ void MemTable::Update(SequenceNumber seq,
  Slice mem_key = lkey.memtable_key();

  std::unique_ptr<MemTableRep::Iterator> iter(
-    table_->GetIterator(lkey.user_key()));
+      table_->GetDynamicPrefixIterator());
  iter->Seek(lkey.internal_key(), mem_key.data());

  if (iter->Valid()) {
@@ -489,7 +519,7 @@ bool MemTable::UpdateCallback(SequenceNumber seq,
  Slice memkey = lkey.memtable_key();

  std::unique_ptr<MemTableRep::Iterator> iter(
-    table_->GetIterator(lkey.user_key()));
+      table_->GetDynamicPrefixIterator());
  iter->Seek(lkey.internal_key(), memkey.data());

  if (iter->Valid()) {
@@ -564,7 +594,7 @@ size_t MemTable::CountSuccessiveMergeEntries(const LookupKey& key) {
  // reps). By passing in the user key, we allow efficient iterator creation.
  // The iterator only needs to be ordered within the same user key.
  std::unique_ptr<MemTableRep::Iterator> iter(
-      table_->GetIterator(key.user_key()));
+      table_->GetDynamicPrefixIterator());
  iter->Seek(key.internal_key(), memkey.data());

  size_t num_successive_merges = 0;
@@ -591,7 +621,7 @@ size_t MemTable::CountSuccessiveMergeEntries(const LookupKey& key) {

 void MemTableRep::Get(const LookupKey& k, void* callback_args,
                      bool (*callback_func)(void* arg, const char* entry)) {
-  auto iter = GetIterator(k.user_key());
+  auto iter = GetDynamicPrefixIterator();
  for (iter->Seek(k.internal_key(), k.memtable_key().data());
       iter->Valid() && callback_func(callback_args, iter->key());
       iter->Next()) {
@@ -21,6 +21,7 @@

 namespace rocksdb {

+class Arena;
 class Mutex;
 class MemTableIterator;
 class MergeContext;
@@ -77,8 +78,12 @@ class MemTable {
  //
  // By default, it returns an iterator for prefix seek if prefix_extractor
  // is configured in Options.
+  // arena: If not null, the arena needs to be used to allocate the Iterator.
+  //        Calling ~Iterator of the iterator will destroy all the states but
+  //        those allocated in arena.
  Iterator* NewIterator(const ReadOptions& options,
-                        bool enforce_total_order = false);
+                        bool enforce_total_order = false,
+                        Arena* arena = nullptr);

  // Add an entry into memtable that maps key to value at the
  // specified sequence number and with the specified type.
@@ -11,6 +11,7 @@
 #include "db/version_set.h"
 #include "rocksdb/env.h"
 #include "rocksdb/iterator.h"
+#include "table/merger.h"
 #include "util/coding.h"
 #include "util/log_buffer.h"

@@ -78,6 +79,14 @@ void MemTableListVersion::AddIterators(const ReadOptions& options,
  }
 }

+void MemTableListVersion::AddIterators(
+    const ReadOptions& options, MergeIteratorBuilder* merge_iter_builder) {
+  for (auto& m : memlist_) {
+    merge_iter_builder->AddIterator(
+        m->NewIterator(options, merge_iter_builder->GetArena()));
+  }
+}
+
 uint64_t MemTableListVersion::GetTotalNumEntries() const {
  uint64_t total_num = 0;
  for (auto& m : memlist_) {
@@ -131,7 +140,7 @@ void MemTableList::PickMemtablesToFlush(autovector<MemTable*>* ret) {

 void MemTableList::RollbackMemtableFlush(const autovector<MemTable*>& mems,
                                         uint64_t file_number,
-                                         std::set<uint64_t>* pending_outputs) {
+                                         FileNumToPathIdMap* pending_outputs) {
  assert(!mems.empty());

  // If the flush was not successful, then just reset state.
@@ -153,7 +162,7 @@ void MemTableList::RollbackMemtableFlush(const autovector<MemTable*>& mems,
 Status MemTableList::InstallMemtableFlushResults(
    ColumnFamilyData* cfd, const autovector<MemTable*>& mems, VersionSet* vset,
    port::Mutex* mu, Logger* info_log, uint64_t file_number,
-    std::set<uint64_t>& pending_outputs, autovector<MemTable*>* to_delete,
+    FileNumToPathIdMap* pending_outputs, autovector<MemTable*>* to_delete,
    Directory* db_directory, LogBuffer* log_buffer) {
  mu->AssertHeld();

@@ -210,7 +219,7 @@ Status MemTableList::InstallMemtableFlushResults(
        // has been written to a committed version so that other concurrently
        // executing compaction threads do not mistakenly assume that this
        // file is not live.
-        pending_outputs.erase(m->file_number_);
+        pending_outputs->erase(m->file_number_);
        if (m->Unref() != nullptr) {
          to_delete->push_back(m);
        }
@@ -224,7 +233,7 @@ Status MemTableList::InstallMemtableFlushResults(
        m->flush_in_progress_ = false;
        m->edit_.Clear();
        num_flush_not_started_++;
-        pending_outputs.erase(m->file_number_);
+        pending_outputs->erase(m->file_number_);
        m->file_number_ = 0;
        imm_flush_needed.Release_Store((void *)1);
      }
@@ -15,6 +15,7 @@
 #include "rocksdb/iterator.h"

 #include "db/dbformat.h"
+#include "db/filename.h"
 #include "db/skiplist.h"
 #include "db/memtable.h"
 #include "rocksdb/db.h"
@@ -28,6 +29,7 @@ namespace rocksdb {
 class ColumnFamilyData;
 class InternalKeyComparator;
 class Mutex;
+class MergeIteratorBuilder;

 // keeps a list of immutable memtables in a vector. the list is immutable
 // if refcount is bigger than one. It is used as a state for Get() and
@@ -49,6 +51,9 @@ class MemTableListVersion {
  void AddIterators(const ReadOptions& options,
                    std::vector<Iterator*>* iterator_list);

+  void AddIterators(const ReadOptions& options,
+                    MergeIteratorBuilder* merge_iter_builder);
+
  uint64_t GetTotalNumEntries() const;

 private:
@@ -104,17 +109,14 @@ class MemTableList {
  // they can get picked up again on the next round of flush.
  void RollbackMemtableFlush(const autovector<MemTable*>& mems,
                             uint64_t file_number,
-                             std::set<uint64_t>* pending_outputs);
+                             FileNumToPathIdMap* pending_outputs);

  // Commit a successful flush in the manifest file
-  Status InstallMemtableFlushResults(ColumnFamilyData* cfd,
-                                     const autovector<MemTable*>& m,
-                                     VersionSet* vset, port::Mutex* mu,
-                                     Logger* info_log, uint64_t file_number,
-                                     std::set<uint64_t>& pending_outputs,
-                                     autovector<MemTable*>* to_delete,
-                                     Directory* db_directory,
-                                     LogBuffer* log_buffer);
+  Status InstallMemtableFlushResults(
+      ColumnFamilyData* cfd, const autovector<MemTable*>& m, VersionSet* vset,
+      port::Mutex* mu, Logger* info_log, uint64_t file_number,
+      FileNumToPathIdMap* pending_outputs, autovector<MemTable*>* to_delete,
+      Directory* db_directory, LogBuffer* log_buffer);

  // New memtables are inserted at the front of the list.
  // Takes ownership of the referenced held on *m by the caller of Add().
@@ -24,10 +24,12 @@ void MergeHelper::MergeUntil(Iterator* iter, SequenceNumber stop_before,
                             bool at_bottom, Statistics* stats, int* steps) {
  // Get a copy of the internal key, before it's invalidated by iter->Next()
  // Also maintain the list of merge operands seen.
+  assert(HasOperator());
  keys_.clear();
  operands_.clear();
  keys_.push_front(iter->key().ToString());
  operands_.push_front(iter->value().ToString());
+  assert(user_merge_operator_);

  success_ = false;   // Will become true if we hit Put/Delete or bottom

@@ -78,13 +78,16 @@ class MergeHelper {
  //   IMPORTANT 2: The entries were traversed in order from BACK to FRONT.
  //                So keys().back() was the first key seen by iterator.
  // TODO: Re-style this comment to be like the first one
-  bool IsSuccess() { return success_; }
-  Slice key() { assert(success_); return Slice(keys_.back()); }
-  Slice value() { assert(success_); return Slice(operands_.back()); }
-  const std::deque<std::string>& keys() { assert(!success_); return keys_; }
-  const std::deque<std::string>& values() {
+  bool IsSuccess() const { return success_; }
+  Slice key() const { assert(success_); return Slice(keys_.back()); }
+  Slice value() const { assert(success_); return Slice(operands_.back()); }
+  const std::deque<std::string>& keys() const {
+    assert(!success_); return keys_;
+  }
+  const std::deque<std::string>& values() const {
    assert(!success_); return operands_;
  }
+  bool HasOperator() const { return user_merge_operator_ != nullptr; }

 private:
  const Comparator* user_comparator_;
@@ -12,12 +12,12 @@
 #include "rocksdb/db.h"
 #include "rocksdb/env.h"
 #include "rocksdb/merge_operator.h"
+#include "rocksdb/utilities/db_ttl.h"
 #include "db/dbformat.h"
 #include "db/db_impl.h"
 #include "db/write_batch_internal.h"
 #include "utilities/merge_operators.h"
 #include "util/testharness.h"
-#include "utilities/db_ttl.h"

 using namespace std;
 using namespace rocksdb;
@@ -212,7 +212,7 @@ class Counters {
  void assert_add(const string& key, uint64_t value) {
    int result = add(key, value);
    assert(result);
-    if (result == 0) exit(1); // Disable unused variable warning. 
+    if (result == 0) exit(1); // Disable unused variable warning.
  }
 };

@@ -460,6 +460,41 @@ void runTest(int argc, const string& dbname, const bool use_ttl = false) {
      }
    }
  }
+
+  {
+    cout << "Test merge-operator not set after reopen\n";
+    {
+      auto db = OpenDb(dbname);
+      MergeBasedCounters counters(db, 0);
+      counters.add("test-key", 1);
+      counters.add("test-key", 1);
+      counters.add("test-key", 1);
+      db->CompactRange(nullptr, nullptr);
+    }
+
+    DB* reopen_db;
+    ASSERT_OK(DB::Open(Options(), dbname, &reopen_db));
+    std::string value;
+    ASSERT_TRUE(!(reopen_db->Get(ReadOptions(), "test-key", &value).ok()));
+    delete reopen_db;
+    DestroyDB(dbname, Options());
+  }
+
+  /* Temporary remove this test
+  {
+    cout << "Test merge-operator not set after reopen (recovery case)\n";
+    {
+      auto db = OpenDb(dbname);
+      MergeBasedCounters counters(db, 0);
+      counters.add("test-key", 1);
+      counters.add("test-key", 1);
+      counters.add("test-key", 1);
+    }
+
+    DB* reopen_db;
+    ASSERT_TRUE(DB::Open(Options(), dbname, &reopen_db).IsInvalidArgument());
+  }
+  */
 }
 }  // namespace

@@ -23,6 +23,7 @@
 #include "rocksdb/slice_transform.h"
 #include "rocksdb/table.h"
 #include "table/meta_blocks.h"
+#include "table/bloom_block.h"
 #include "table/plain_table_factory.h"
 #include "table/plain_table_reader.h"
 #include "util/hash.h"
@@ -61,7 +62,20 @@ class PlainTableDBTest {
  // Return the current option configuration.
  Options CurrentOptions() {
    Options options;
-    options.table_factory.reset(NewPlainTableFactory(16, 2, 0.8, 3));
+
+    PlainTableOptions plain_table_options;
+    plain_table_options.user_key_len = 0;
+    plain_table_options.bloom_bits_per_key = 2;
+    plain_table_options.hash_table_ratio = 0.8;
+    plain_table_options.index_sparseness = 3;
+    plain_table_options.huge_page_tlb_size = 0;
+    plain_table_options.encoding_type = kPrefix;
+    plain_table_options.full_scan_mode = false;
+    plain_table_options.store_index_in_file = false;
+
+    options.table_factory.reset(NewPlainTableFactory(plain_table_options));
+    options.memtable_factory.reset(NewHashLinkListRepFactory(4, 0, 3, true));
+
    options.prefix_extractor.reset(NewFixedPrefixTransform(8));
    options.allow_mmap_reads = true;
    return options;
@@ -174,21 +188,42 @@ TEST(PlainTableDBTest, Empty) {
  ASSERT_EQ("NOT_FOUND", Get("0000000000000foo"));
 }

+extern const uint64_t kPlainTableMagicNumber;
+
 class TestPlainTableReader : public PlainTableReader {
 public:
  TestPlainTableReader(const EnvOptions& storage_options,
                       const InternalKeyComparator& icomparator,
-                       uint64_t file_size, int bloom_bits_per_key,
-                       double hash_table_ratio, size_t index_sparseness,
+                       EncodingType encoding_type, uint64_t file_size,
+                       int bloom_bits_per_key, double hash_table_ratio,
+                       size_t index_sparseness,
                       const TableProperties* table_properties,
                       unique_ptr<RandomAccessFile>&& file,
-                       const Options& options, bool* expect_bloom_not_match)
+                       const Options& options, bool* expect_bloom_not_match,
+                       bool store_index_in_file)
      : PlainTableReader(options, std::move(file), storage_options, icomparator,
-                         file_size, bloom_bits_per_key, hash_table_ratio,
-                         index_sparseness, table_properties, 2 * 1024 * 1024),
+                         encoding_type, file_size, table_properties),
        expect_bloom_not_match_(expect_bloom_not_match) {
-    Status s = PopulateIndex(const_cast<TableProperties*>(table_properties));
+    Status s = MmapDataFile();
    ASSERT_TRUE(s.ok());
+
+    s = PopulateIndex(const_cast<TableProperties*>(table_properties),
+                      bloom_bits_per_key, hash_table_ratio, index_sparseness,
+                      2 * 1024 * 1024);
+    ASSERT_TRUE(s.ok());
+
+    TableProperties* props = const_cast<TableProperties*>(table_properties);
+    if (store_index_in_file) {
+      auto bloom_version_ptr = props->user_collected_properties.find(
+          PlainTablePropertyNames::kBloomVersion);
+      ASSERT_TRUE(bloom_version_ptr != props->user_collected_properties.end());
+      ASSERT_EQ(bloom_version_ptr->second, std::string("1"));
+      if (options.bloom_locality > 0) {
+        auto num_blocks_ptr = props->user_collected_properties.find(
+            PlainTablePropertyNames::kNumBloomBlocks);
+        ASSERT_TRUE(num_blocks_ptr != props->user_collected_properties.end());
+      }
+    }
  }

  virtual ~TestPlainTableReader() {}
@@ -196,7 +231,11 @@ class TestPlainTableReader : public PlainTableReader {
 private:
  virtual bool MatchBloom(uint32_t hash) const override {
    bool ret = PlainTableReader::MatchBloom(hash);
-    ASSERT_TRUE(!*expect_bloom_not_match_ || !ret);
+    if (*expect_bloom_not_match_) {
+      ASSERT_TRUE(!ret);
+    } else {
+      ASSERT_TRUE(ret);
+    }
    return ret;
  }
  bool* expect_bloom_not_match_;
@@ -206,15 +245,12 @@ extern const uint64_t kPlainTableMagicNumber;
 class TestPlainTableFactory : public PlainTableFactory {
 public:
  explicit TestPlainTableFactory(bool* expect_bloom_not_match,
-                                 uint32_t user_key_len, int bloom_bits_per_key,
-                                 double hash_table_ratio,
-                                 size_t index_sparseness,
-                                 size_t huge_page_tlb_size)
-      : PlainTableFactory(user_key_len, user_key_len, hash_table_ratio,
-                          index_sparseness, huge_page_tlb_size),
-        bloom_bits_per_key_(bloom_bits_per_key),
-        hash_table_ratio_(hash_table_ratio),
-        index_sparseness_(index_sparseness),
+                                 const PlainTableOptions& options)
+      : PlainTableFactory(options),
+        bloom_bits_per_key_(options.bloom_bits_per_key),
+        hash_table_ratio_(options.hash_table_ratio),
+        index_sparseness_(options.index_sparseness),
+        store_index_in_file_(options.store_index_in_file),
        expect_bloom_not_match_(expect_bloom_not_match) {}

  Status NewTableReader(const Options& options, const EnvOptions& soptions,
@@ -226,10 +262,32 @@ class TestPlainTableFactory : public PlainTableFactory {
                                 options.env, options.info_log.get(), &props);
    ASSERT_TRUE(s.ok());

+    if (store_index_in_file_) {
+      BlockHandle bloom_block_handle;
+      s = FindMetaBlock(file.get(), file_size, kPlainTableMagicNumber,
+                        options.env, BloomBlockBuilder::kBloomBlock,
+                        &bloom_block_handle);
+      ASSERT_TRUE(s.ok());
+
+      BlockHandle index_block_handle;
+      s = FindMetaBlock(
+          file.get(), file_size, kPlainTableMagicNumber, options.env,
+          PlainTableIndexBuilder::kPlainTableIndexBlock, &index_block_handle);
+      ASSERT_TRUE(s.ok());
+    }
+
+    auto& user_props = props->user_collected_properties;
+    auto encoding_type_prop =
+        user_props.find(PlainTablePropertyNames::kEncodingType);
+    assert(encoding_type_prop != user_props.end());
+    EncodingType encoding_type = static_cast<EncodingType>(
+        DecodeFixed32(encoding_type_prop->second.c_str()));
+
    std::unique_ptr<PlainTableReader> new_reader(new TestPlainTableReader(
-        soptions, internal_comparator, file_size, bloom_bits_per_key_,
-        hash_table_ratio_, index_sparseness_, props, std::move(file), options,
-        expect_bloom_not_match_));
+        soptions, internal_comparator, encoding_type, file_size,
+        bloom_bits_per_key_, hash_table_ratio_, index_sparseness_, props,
+        std::move(file), options, expect_bloom_not_match_,
+        store_index_in_file_));

    *table = std::move(new_reader);
    return s;
@@ -239,44 +297,92 @@ class TestPlainTableFactory : public PlainTableFactory {
  int bloom_bits_per_key_;
  double hash_table_ratio_;
  size_t index_sparseness_;
+  bool store_index_in_file_;
  bool* expect_bloom_not_match_;
 };

 TEST(PlainTableDBTest, Flush) {
  for (size_t huge_page_tlb_size = 0; huge_page_tlb_size <= 2 * 1024 * 1024;
       huge_page_tlb_size += 2 * 1024 * 1024) {
+    for (EncodingType encoding_type : {kPlain, kPrefix}) {
    for (int bloom_bits = 0; bloom_bits <= 117; bloom_bits += 117) {
      for (int total_order = 0; total_order <= 1; total_order++) {
-        Options options = CurrentOptions();
-        options.create_if_missing = true;
-        // Set only one bucket to force bucket conflict.
-        // Test index interval for the same prefix to be 1, 2 and 4
-        if (total_order) {
-          options.table_factory.reset(NewTotalOrderPlainTableFactory(
-              16, bloom_bits, 2, huge_page_tlb_size));
-        } else {
-          options.table_factory.reset(NewPlainTableFactory(
-              16, bloom_bits, 0.75, 16, huge_page_tlb_size));
+        for (int store_index_in_file = 0; store_index_in_file <= 1;
+             ++store_index_in_file) {
+          if (!bloom_bits && store_index_in_file) {
+            continue;
+          }
+
+          Options options = CurrentOptions();
+          options.create_if_missing = true;
+          // Set only one bucket to force bucket conflict.
+          // Test index interval for the same prefix to be 1, 2 and 4
+          if (total_order) {
+            options.prefix_extractor.reset();
+
+            PlainTableOptions plain_table_options;
+            plain_table_options.user_key_len = 0;
+            plain_table_options.bloom_bits_per_key = bloom_bits;
+            plain_table_options.hash_table_ratio = 0;
+            plain_table_options.index_sparseness = 2;
+            plain_table_options.huge_page_tlb_size = huge_page_tlb_size;
+            plain_table_options.encoding_type = encoding_type;
+            plain_table_options.full_scan_mode = false;
+            plain_table_options.store_index_in_file = store_index_in_file;
+
+            options.table_factory.reset(
+                NewPlainTableFactory(plain_table_options));
+          } else {
+            PlainTableOptions plain_table_options;
+            plain_table_options.user_key_len = 0;
+            plain_table_options.bloom_bits_per_key = bloom_bits;
+            plain_table_options.hash_table_ratio = 0.75;
+            plain_table_options.index_sparseness = 16;
+            plain_table_options.huge_page_tlb_size = huge_page_tlb_size;
+            plain_table_options.encoding_type = encoding_type;
+            plain_table_options.full_scan_mode = false;
+            plain_table_options.store_index_in_file = store_index_in_file;
+
+            options.table_factory.reset(
+                NewPlainTableFactory(plain_table_options));
+          }
+          DestroyAndReopen(&options);
+          uint64_t int_num;
+          ASSERT_TRUE(dbfull()->GetIntProperty(
+              "rocksdb.estimate-table-readers-mem", &int_num));
+          ASSERT_EQ(int_num, 0U);
+
+          ASSERT_OK(Put("1000000000000foo", "v1"));
+          ASSERT_OK(Put("0000000000000bar", "v2"));
+          ASSERT_OK(Put("1000000000000foo", "v3"));
+          dbfull()->TEST_FlushMemTable();
+
+          ASSERT_TRUE(dbfull()->GetIntProperty(
+              "rocksdb.estimate-table-readers-mem", &int_num));
+          ASSERT_GT(int_num, 0U);
+
+          TablePropertiesCollection ptc;
+          reinterpret_cast<DB*>(dbfull())->GetPropertiesOfAllTables(&ptc);
+          ASSERT_EQ(1U, ptc.size());
+          auto row = ptc.begin();
+          auto tp = row->second;
+
+          if (!store_index_in_file) {
+            ASSERT_EQ(total_order ? "4" : "12",
+                      (tp->user_collected_properties)
+                          .at("plain_table_hash_table_size"));
+            ASSERT_EQ("0", (tp->user_collected_properties)
+                               .at("plain_table_sub_index_size"));
+          } else {
+            ASSERT_EQ("0", (tp->user_collected_properties)
+                               .at("plain_table_hash_table_size"));
+            ASSERT_EQ("0", (tp->user_collected_properties)
+                               .at("plain_table_sub_index_size"));
+          }
+          ASSERT_EQ("v3", Get("1000000000000foo"));
+          ASSERT_EQ("v2", Get("0000000000000bar"));
+        }
        }
-        DestroyAndReopen(&options);
-
-        ASSERT_OK(Put("1000000000000foo", "v1"));
-        ASSERT_OK(Put("0000000000000bar", "v2"));
-        ASSERT_OK(Put("1000000000000foo", "v3"));
-        dbfull()->TEST_FlushMemTable();
-
-        TablePropertiesCollection ptc;
-        reinterpret_cast<DB*>(dbfull())->GetPropertiesOfAllTables(&ptc);
-        ASSERT_EQ(1U, ptc.size());
-        auto row = ptc.begin();
-        auto tp = row->second;
-        ASSERT_EQ(total_order ? "4" : "12", (tp->user_collected_properties).at(
-                                                "plain_table_hash_table_size"));
-        ASSERT_EQ(total_order ? "9" : "0", (tp->user_collected_properties).at(
-                                               "plain_table_sub_index_size"));
-
-        ASSERT_EQ("v3", Get("1000000000000foo"));
-        ASSERT_EQ("v2", Get("0000000000000bar"));
      }
    }
  }
@@ -285,23 +391,42 @@ TEST(PlainTableDBTest, Flush) {
 TEST(PlainTableDBTest, Flush2) {
  for (size_t huge_page_tlb_size = 0; huge_page_tlb_size <= 2 * 1024 * 1024;
       huge_page_tlb_size += 2 * 1024 * 1024) {
+    for (EncodingType encoding_type : {kPlain, kPrefix}) {
    for (int bloom_bits = 0; bloom_bits <= 117; bloom_bits += 117) {
      for (int total_order = 0; total_order <= 1; total_order++) {
+        for (int store_index_in_file = 0; store_index_in_file <= 1;
+             ++store_index_in_file) {
+          if (encoding_type == kPrefix && total_order) {
+            continue;
+          }
+          if (!bloom_bits && store_index_in_file) {
+            continue;
+          }
+          if (total_order && store_index_in_file) {
+          continue;
+        }
        bool expect_bloom_not_match = false;
        Options options = CurrentOptions();
        options.create_if_missing = true;
        // Set only one bucket to force bucket conflict.
        // Test index interval for the same prefix to be 1, 2 and 4
+        PlainTableOptions plain_table_options;
        if (total_order) {
          options.prefix_extractor = nullptr;
-          options.table_factory.reset(
-              new TestPlainTableFactory(&expect_bloom_not_match, 16, bloom_bits,
-                                        0, 2, huge_page_tlb_size));
+          plain_table_options.hash_table_ratio = 0;
+          plain_table_options.index_sparseness = 2;
        } else {
-          options.table_factory.reset(
-              new TestPlainTableFactory(&expect_bloom_not_match, 16, bloom_bits,
-                                        0.75, 16, huge_page_tlb_size));
+          plain_table_options.hash_table_ratio = 0.75;
+          plain_table_options.index_sparseness = 16;
        }
+        plain_table_options.user_key_len = kPlainTableVariableLength;
+        plain_table_options.bloom_bits_per_key = bloom_bits;
+        plain_table_options.huge_page_tlb_size = huge_page_tlb_size;
+        plain_table_options.encoding_type = encoding_type;
+        plain_table_options.store_index_in_file = store_index_in_file;
+        options.table_factory.reset(new TestPlainTableFactory(
+            &expect_bloom_not_match, plain_table_options));
+
        DestroyAndReopen(&options);
        ASSERT_OK(Put("0000000000000bar", "b"));
        ASSERT_OK(Put("1000000000000foo", "v1"));
@@ -329,7 +454,6 @@ TEST(PlainTableDBTest, Flush2) {
          // Neither key nor value should exist.
          expect_bloom_not_match = true;
          ASSERT_EQ("NOT_FOUND", Get("5_not00000000bar"));
-
          // Key doesn't exist any more but prefix exists.
          if (total_order) {
            ASSERT_EQ("NOT_FOUND", Get("1000000000000not"));
@@ -338,6 +462,8 @@ TEST(PlainTableDBTest, Flush2) {
          expect_bloom_not_match = false;
        }
      }
+      }
+    }
    }
  }
 }
@@ -345,8 +471,12 @@ TEST(PlainTableDBTest, Flush2) {
 TEST(PlainTableDBTest, Iterator) {
  for (size_t huge_page_tlb_size = 0; huge_page_tlb_size <= 2 * 1024 * 1024;
       huge_page_tlb_size += 2 * 1024 * 1024) {
+    for (EncodingType encoding_type : {kPlain, kPrefix}) {
    for (int bloom_bits = 0; bloom_bits <= 117; bloom_bits += 117) {
      for (int total_order = 0; total_order <= 1; total_order++) {
+        if (encoding_type == kPrefix && total_order == 1) {
+          continue;
+        }
        bool expect_bloom_not_match = false;
        Options options = CurrentOptions();
        options.create_if_missing = true;
@@ -354,13 +484,28 @@ TEST(PlainTableDBTest, Iterator) {
        // Test index interval for the same prefix to be 1, 2 and 4
        if (total_order) {
          options.prefix_extractor = nullptr;
-          options.table_factory.reset(
-              new TestPlainTableFactory(&expect_bloom_not_match, 16, bloom_bits,
-                                        0, 2, huge_page_tlb_size));
+
+          PlainTableOptions plain_table_options;
+          plain_table_options.user_key_len = 16;
+          plain_table_options.bloom_bits_per_key = bloom_bits;
+          plain_table_options.hash_table_ratio = 0;
+          plain_table_options.index_sparseness = 2;
+          plain_table_options.huge_page_tlb_size = huge_page_tlb_size;
+          plain_table_options.encoding_type = encoding_type;
+
+          options.table_factory.reset(new TestPlainTableFactory(
+              &expect_bloom_not_match, plain_table_options));
        } else {
-          options.table_factory.reset(
-              new TestPlainTableFactory(&expect_bloom_not_match, 16, bloom_bits,
-                                        0.75, 16, huge_page_tlb_size));
+          PlainTableOptions plain_table_options;
+          plain_table_options.user_key_len = 16;
+          plain_table_options.bloom_bits_per_key = bloom_bits;
+          plain_table_options.hash_table_ratio = 0.75;
+          plain_table_options.index_sparseness = 16;
+          plain_table_options.huge_page_tlb_size = huge_page_tlb_size;
+          plain_table_options.encoding_type = encoding_type;
+
+          options.table_factory.reset(new TestPlainTableFactory(
+              &expect_bloom_not_match, plain_table_options));
        }
        DestroyAndReopen(&options);

@@ -447,6 +592,7 @@ TEST(PlainTableDBTest, Iterator) {
        delete iter;
      }
    }
+    }
  }
 }

@@ -458,7 +604,13 @@ std::string MakeLongKey(size_t length, char c) {

 TEST(PlainTableDBTest, IteratorLargeKeys) {
  Options options = CurrentOptions();
-  options.table_factory.reset(NewTotalOrderPlainTableFactory(0, 0, 16));
+
+  PlainTableOptions plain_table_options;
+  plain_table_options.user_key_len = 0;
+  plain_table_options.bloom_bits_per_key = 0;
+  plain_table_options.hash_table_ratio = 0;
+
+  options.table_factory.reset(NewPlainTableFactory(plain_table_options));
  options.create_if_missing = true;
  options.prefix_extractor.reset();
  DestroyAndReopen(&options);
@@ -494,6 +646,54 @@ TEST(PlainTableDBTest, IteratorLargeKeys) {
  delete iter;
 }

+namespace {
+std::string MakeLongKeyWithPrefix(size_t length, char c) {
+  return "00000000" + std::string(length - 8, c);
+}
+}  // namespace
+
+TEST(PlainTableDBTest, IteratorLargeKeysWithPrefix) {
+  Options options = CurrentOptions();
+
+  PlainTableOptions plain_table_options;
+  plain_table_options.user_key_len = 16;
+  plain_table_options.bloom_bits_per_key = 0;
+  plain_table_options.hash_table_ratio = 0.8;
+  plain_table_options.index_sparseness = 3;
+  plain_table_options.huge_page_tlb_size = 0;
+  plain_table_options.encoding_type = kPrefix;
+
+  options.table_factory.reset(NewPlainTableFactory(plain_table_options));
+  options.create_if_missing = true;
+  DestroyAndReopen(&options);
+
+  std::string key_list[] = {
+      MakeLongKeyWithPrefix(30, '0'), MakeLongKeyWithPrefix(16, '1'),
+      MakeLongKeyWithPrefix(32, '2'), MakeLongKeyWithPrefix(60, '3'),
+      MakeLongKeyWithPrefix(90, '4'), MakeLongKeyWithPrefix(50, '5'),
+      MakeLongKeyWithPrefix(26, '6')};
+
+  for (size_t i = 0; i < 7; i++) {
+    ASSERT_OK(Put(key_list[i], std::to_string(i)));
+  }
+
+  dbfull()->TEST_FlushMemTable();
+
+  Iterator* iter = dbfull()->NewIterator(ReadOptions());
+  iter->Seek(key_list[0]);
+
+  for (size_t i = 0; i < 7; i++) {
+    ASSERT_TRUE(iter->Valid());
+    ASSERT_EQ(key_list[i], iter->key().ToString());
+    ASSERT_EQ(std::to_string(i), iter->value().ToString());
+    iter->Next();
+  }
+
+  ASSERT_TRUE(!iter->Valid());
+
+  delete iter;
+}
+
 // A test comparator which compare two strings in this way:
 // (1) first compare prefix of 8 bytes in alphabet order,
 // (2) if two strings share the same prefix, sort the other part of the string
@@ -599,8 +799,16 @@ TEST(PlainTableDBTest, HashBucketConflict) {
      options.create_if_missing = true;
      // Set only one bucket to force bucket conflict.
      // Test index interval for the same prefix to be 1, 2 and 4
-      options.table_factory.reset(
-          NewTotalOrderPlainTableFactory(16, 0, 2 ^ i, huge_page_tlb_size));
+
+      PlainTableOptions plain_table_options;
+      plain_table_options.user_key_len = 16;
+      plain_table_options.bloom_bits_per_key = 0;
+      plain_table_options.hash_table_ratio = 0;
+      plain_table_options.index_sparseness = 2 ^ i;
+      plain_table_options.huge_page_tlb_size = huge_page_tlb_size;
+
+      options.table_factory.reset(NewPlainTableFactory(plain_table_options));
+
      DestroyAndReopen(&options);
      ASSERT_OK(Put("5000000000000fo0", "v1"));
      ASSERT_OK(Put("5000000000000fo1", "v2"));
@@ -686,8 +894,15 @@ TEST(PlainTableDBTest, HashBucketConflictReverseSuffixComparator) {
      options.comparator = &comp;
      // Set only one bucket to force bucket conflict.
      // Test index interval for the same prefix to be 1, 2 and 4
-      options.table_factory.reset(
-          NewTotalOrderPlainTableFactory(16, 0, 2 ^ i, huge_page_tlb_size));
+
+      PlainTableOptions plain_table_options;
+      plain_table_options.user_key_len = 16;
+      plain_table_options.bloom_bits_per_key = 0;
+      plain_table_options.hash_table_ratio = 0;
+      plain_table_options.index_sparseness = 2 ^ i;
+      plain_table_options.huge_page_tlb_size = huge_page_tlb_size;
+
+      options.table_factory.reset(NewPlainTableFactory(plain_table_options));
      DestroyAndReopen(&options);
      ASSERT_OK(Put("5000000000000fo0", "v1"));
      ASSERT_OK(Put("5000000000000fo1", "v2"));
@@ -767,7 +982,13 @@ TEST(PlainTableDBTest, NonExistingKeyToNonEmptyBucket) {
  options.create_if_missing = true;
  // Set only one bucket to force bucket conflict.
  // Test index interval for the same prefix to be 1, 2 and 4
-  options.table_factory.reset(NewTotalOrderPlainTableFactory(16, 0, 5));
+  PlainTableOptions plain_table_options;
+  plain_table_options.user_key_len = 16;
+  plain_table_options.bloom_bits_per_key = 0;
+  plain_table_options.hash_table_ratio = 0;
+  plain_table_options.index_sparseness = 5;
+
+  options.table_factory.reset(NewPlainTableFactory(plain_table_options));
  DestroyAndReopen(&options);
  ASSERT_OK(Put("5000000000000fo0", "v1"));
  ASSERT_OK(Put("5000000000000fo1", "v2"));
@@ -846,6 +1067,49 @@ TEST(PlainTableDBTest, CompactionTrigger) {
  ASSERT_EQ(NumTableFilesAtLevel(1), 1);
 }

+TEST(PlainTableDBTest, AdaptiveTable) {
+  Options options = CurrentOptions();
+  options.create_if_missing = true;
+
+  options.table_factory.reset(NewPlainTableFactory());
+  DestroyAndReopen(&options);
+
+  ASSERT_OK(Put("1000000000000foo", "v1"));
+  ASSERT_OK(Put("0000000000000bar", "v2"));
+  ASSERT_OK(Put("1000000000000foo", "v3"));
+  dbfull()->TEST_FlushMemTable();
+
+  options.create_if_missing = false;
+  std::shared_ptr<TableFactory> dummy_factory;
+  std::shared_ptr<TableFactory> block_based_factory(
+      NewBlockBasedTableFactory());
+  options.table_factory.reset(NewAdaptiveTableFactory(
+      block_based_factory, dummy_factory, dummy_factory));
+  Reopen(&options);
+  ASSERT_EQ("v3", Get("1000000000000foo"));
+  ASSERT_EQ("v2", Get("0000000000000bar"));
+
+  ASSERT_OK(Put("2000000000000foo", "v4"));
+  ASSERT_OK(Put("3000000000000bar", "v5"));
+  dbfull()->TEST_FlushMemTable();
+  ASSERT_EQ("v4", Get("2000000000000foo"));
+  ASSERT_EQ("v5", Get("3000000000000bar"));
+
+  Reopen(&options);
+  ASSERT_EQ("v3", Get("1000000000000foo"));
+  ASSERT_EQ("v2", Get("0000000000000bar"));
+  ASSERT_EQ("v4", Get("2000000000000foo"));
+  ASSERT_EQ("v5", Get("3000000000000bar"));
+
+  options.table_factory.reset(NewBlockBasedTableFactory());
+  Reopen(&options);
+  ASSERT_NE("v3", Get("1000000000000foo"));
+
+  options.table_factory.reset(NewPlainTableFactory());
+  Reopen(&options);
+  ASSERT_NE("v5", Get("3000000000000bar"));
+}
+
 }  // namespace rocksdb

 int main(int argc, char** argv) {
@@ -3,6 +3,14 @@
 //  LICENSE file in the root directory of this source tree. An additional grant
 //  of patent rights can be found in the PATENTS file in the same directory.

+#ifndef GFLAGS
+#include <cstdio>
+int main() {
+  fprintf(stderr, "Please install gflags to run rocksdb tools\n");
+  return 1;
+}
+#else
+
 #include <algorithm>
 #include <iostream>
 #include <vector>
@@ -17,6 +25,8 @@
 #include "util/stop_watch.h"
 #include "util/testharness.h"

+using GFLAGS::ParseCommandLineFlags;
+
 DEFINE_bool(trigger_deadlock, false,
            "issue delete in range scan to trigger PrefixHashMap deadlock");
 DEFINE_uint64(bucket_count, 100000, "number of buckets");
@@ -179,6 +189,10 @@ class PrefixTest {
          options.memtable_factory.reset(
              NewHashLinkListRepFactory(bucket_count, 2 * 1024 * 1024));
          return true;
+        case kHashLinkListTriggerSkipList:
+          options.memtable_factory.reset(
+              NewHashLinkListRepFactory(bucket_count, 0, 3));
+          return true;
        default:
          return false;
      }
@@ -198,6 +212,7 @@ class PrefixTest {
    kHashSkipList,
    kHashLinkList,
    kHashLinkListHugePageTlb,
+    kHashLinkListTriggerSkipList,
    kEnd
  };
  int option_config_;
@@ -479,9 +494,11 @@ TEST(PrefixTest, DynamicPrefixIterator) {
 }

 int main(int argc, char** argv) {
-  google::ParseCommandLineFlags(&argc, &argv, true);
+  ParseCommandLineFlags(&argc, &argv, true);
  std::cout << kDbName << "\n";

  rocksdb::test::RunAllTests();
  return 0;
 }
+
+#endif  // GFLAGS
@@ -31,6 +31,8 @@

 #ifndef ROCKSDB_LITE

+#define __STDC_FORMAT_MACROS
+#include <inttypes.h>
 #include "db/builder.h"
 #include "db/db_impl.h"
 #include "db/dbformat.h"
@@ -63,8 +65,8 @@ class Repairer {
            NewLRUCache(10, options_.table_cache_numshardbits,
                        options_.table_cache_remove_scan_count_limit)),
        next_file_number_(1) {
-    table_cache_ = new TableCache(dbname_, &options_, storage_options_,
-                                  raw_table_cache_.get());
+    table_cache_ =
+        new TableCache(&options_, storage_options_, raw_table_cache_.get());
    edit_ = new VersionEdit();
  }

@@ -82,18 +84,17 @@ class Repairer {
      status = WriteDescriptor();
    }
    if (status.ok()) {
-      unsigned long long bytes = 0;
+      uint64_t bytes = 0;
      for (size_t i = 0; i < tables_.size(); i++) {
-        bytes += tables_[i].meta.file_size;
+        bytes += tables_[i].meta.fd.GetFileSize();
      }
      Log(options_.info_log,
          "**** Repaired rocksdb %s; "
-          "recovered %d files; %llu bytes. "
+          "recovered %zu files; %" PRIu64
+          "bytes. "
          "Some data may have been lost. "
          "****",
-          dbname_.c_str(),
-          static_cast<int>(tables_.size()),
-          bytes);
+          dbname_.c_str(), tables_.size(), bytes);
    }
    return status;
  }
@@ -115,7 +116,7 @@ class Repairer {
  VersionEdit* edit_;

  std::vector<std::string> manifests_;
-  std::vector<uint64_t> table_numbers_;
+  std::vector<FileDescriptor> table_fds_;
  std::vector<uint64_t> logs_;
  std::vector<TableInfo> tables_;
  uint64_t next_file_number_;
@@ -123,35 +124,44 @@ class Repairer {

  Status FindFiles() {
    std::vector<std::string> filenames;
-    Status status = env_->GetChildren(dbname_, &filenames);
-    if (!status.ok()) {
-      return status;
-    }
-    if (filenames.empty()) {
-      return Status::Corruption(dbname_, "repair found no files");
-    }
+    bool found_file = false;
+    for (uint32_t path_id = 0; path_id < options_.db_paths.size(); path_id++) {
+      Status status =
+          env_->GetChildren(options_.db_paths[path_id].path, &filenames);
+      if (!status.ok()) {
+        return status;
+      }
+      if (!filenames.empty()) {
+        found_file = true;
+      }

-    uint64_t number;
-    FileType type;
-    for (size_t i = 0; i < filenames.size(); i++) {
-      if (ParseFileName(filenames[i], &number, &type)) {
-        if (type == kDescriptorFile) {
-          manifests_.push_back(filenames[i]);
-        } else {
-          if (number + 1 > next_file_number_) {
-            next_file_number_ = number + 1;
-          }
-          if (type == kLogFile) {
-            logs_.push_back(number);
-          } else if (type == kTableFile) {
-            table_numbers_.push_back(number);
+      uint64_t number;
+      FileType type;
+      for (size_t i = 0; i < filenames.size(); i++) {
+        if (ParseFileName(filenames[i], &number, &type)) {
+          if (type == kDescriptorFile) {
+            assert(path_id == 0);
+            manifests_.push_back(filenames[i]);
          } else {
-            // Ignore other files
+            if (number + 1 > next_file_number_) {
+              next_file_number_ = number + 1;
+            }
+            if (type == kLogFile) {
+              assert(path_id == 0);
+              logs_.push_back(number);
+            } else if (type == kTableFile) {
+              table_fds_.emplace_back(number, path_id, 0);
+            } else {
+              // Ignore other files
+            }
          }
        }
      }
    }
-    return status;
+    if (!found_file) {
+      return Status::Corruption(dbname_, "repair found no files");
+    }
+    return Status::OK();
  }

  void ConvertLogFilesToTables() {
@@ -159,8 +169,8 @@ class Repairer {
      std::string logname = LogFileName(dbname_, logs_[i]);
      Status status = ConvertLogToTable(logs_[i]);
      if (!status.ok()) {
-        Log(options_.info_log, "Log #%llu: ignoring conversion error: %s",
-            (unsigned long long) logs_[i],
+        Log(options_.info_log,
+            "Log #%" PRIu64 ": ignoring conversion error: %s", logs_[i],
            status.ToString().c_str());
      }
      ArchiveFile(logname);
@@ -174,10 +184,8 @@ class Repairer {
      uint64_t lognum;
      virtual void Corruption(size_t bytes, const Status& s) {
        // We print error messages for corruption, but continue repairing.
-        Log(info_log, "Log #%llu: dropping %d bytes; %s",
-            (unsigned long long) lognum,
-            static_cast<int>(bytes),
-            s.ToString().c_str());
+        Log(info_log, "Log #%" PRIu64 ": dropping %d bytes; %s", lognum,
+            static_cast<int>(bytes), s.ToString().c_str());
      }
    };

@@ -220,8 +228,7 @@ class Repairer {
      if (status.ok()) {
        counter += WriteBatchInternal::Count(&batch);
      } else {
-        Log(options_.info_log, "Log #%llu: ignoring %s",
-            (unsigned long long) log,
+        Log(options_.info_log, "Log #%" PRIu64 ": ignoring %s", log,
            status.ToString().c_str());
        status = Status::OK();  // Keep going with rest of file
      }
@@ -230,7 +237,7 @@ class Repairer {
    // Do not record a version edit for this conversion to a Table
    // since ExtractMetaData() will also generate edits.
    FileMetaData meta;
-    meta.number = next_file_number_++;
+    meta.fd = FileDescriptor(next_file_number_++, 0, 0);
    ReadOptions ro;
    Iterator* iter = mem->NewIterator(ro, true /* enforce_total_order */);
    status = BuildTable(dbname_, env_, options_, storage_options_, table_cache_,
@@ -240,27 +247,27 @@ class Repairer {
    delete cf_mems_default;
    mem = nullptr;
    if (status.ok()) {
-      if (meta.file_size > 0) {
-        table_numbers_.push_back(meta.number);
+      if (meta.fd.GetFileSize() > 0) {
+        table_fds_.push_back(meta.fd);
      }
    }
-    Log(options_.info_log, "Log #%llu: %d ops saved to Table #%llu %s",
-        (unsigned long long) log,
-        counter,
-        (unsigned long long) meta.number,
-        status.ToString().c_str());
+    Log(options_.info_log,
+        "Log #%" PRIu64 ": %d ops saved to Table #%" PRIu64 " %s", log, counter,
+        meta.fd.GetNumber(), status.ToString().c_str());
    return status;
  }

  void ExtractMetaData() {
-    for (size_t i = 0; i < table_numbers_.size(); i++) {
+    for (size_t i = 0; i < table_fds_.size(); i++) {
      TableInfo t;
-      t.meta.number = table_numbers_[i];
+      t.meta.fd = table_fds_[i];
      Status status = ScanTable(&t);
      if (!status.ok()) {
-        std::string fname = TableFileName(dbname_, table_numbers_[i]);
-        Log(options_.info_log, "Table #%llu: ignoring %s",
-            (unsigned long long) table_numbers_[i],
+        std::string fname = TableFileName(
+            options_.db_paths, t.meta.fd.GetNumber(), t.meta.fd.GetPathId());
+        Log(options_.info_log, "Table #%s: ignoring %s",
+            FormatFileNumber(t.meta.fd.GetNumber(), t.meta.fd.GetPathId())
+                .c_str(),
            status.ToString().c_str());
        ArchiveFile(fname);
      } else {
@@ -270,13 +277,16 @@ class Repairer {
  }

  Status ScanTable(TableInfo* t) {
-    std::string fname = TableFileName(dbname_, t->meta.number);
+    std::string fname = TableFileName(options_.db_paths, t->meta.fd.GetNumber(),
+                                      t->meta.fd.GetPathId());
    int counter = 0;
-    Status status = env_->GetFileSize(fname, &t->meta.file_size);
+    uint64_t file_size;
+    Status status = env_->GetFileSize(fname, &file_size);
+    t->meta.fd = FileDescriptor(t->meta.fd.GetNumber(), t->meta.fd.GetPathId(),
+                                file_size);
    if (status.ok()) {
-      FileMetaData dummy_meta(t->meta.number, t->meta.file_size);
      Iterator* iter = table_cache_->NewIterator(
-          ReadOptions(), storage_options_, icmp_, dummy_meta);
+          ReadOptions(), storage_options_, icmp_, t->meta.fd);
      bool empty = true;
      ParsedInternalKey parsed;
      t->min_sequence = 0;
@@ -284,9 +294,8 @@ class Repairer {
      for (iter->SeekToFirst(); iter->Valid(); iter->Next()) {
        Slice key = iter->key();
        if (!ParseInternalKey(key, &parsed)) {
-          Log(options_.info_log, "Table #%llu: unparsable key %s",
-              (unsigned long long) t->meta.number,
-              EscapeString(key).c_str());
+          Log(options_.info_log, "Table #%" PRIu64 ": unparsable key %s",
+              t->meta.fd.GetNumber(), EscapeString(key).c_str());
          continue;
        }

@@ -308,10 +317,8 @@ class Repairer {
      }
      delete iter;
    }
-    Log(options_.info_log, "Table #%llu: %d entries %s",
-        (unsigned long long) t->meta.number,
-        counter,
-        status.ToString().c_str());
+    Log(options_.info_log, "Table #%" PRIu64 ": %d entries %s",
+        t->meta.fd.GetNumber(), counter, status.ToString().c_str());
    return status;
  }

@@ -339,9 +346,9 @@ class Repairer {
    for (size_t i = 0; i < tables_.size(); i++) {
      // TODO(opt): separate out into multiple levels
      const TableInfo& t = tables_[i];
-      edit_->AddFile(0, t.meta.number, t.meta.file_size,
-                    t.meta.smallest, t.meta.largest,
-                    t.min_sequence, t.max_sequence);
+      edit_->AddFile(0, t.meta.fd.GetNumber(), t.meta.fd.GetPathId(),
+                     t.meta.fd.GetFileSize(), t.meta.smallest, t.meta.largest,
+                     t.min_sequence, t.max_sequence);
    }

    //fprintf(stderr, "NewDescriptor:\n%s\n", edit_.DebugString().c_str());
@@ -363,7 +370,7 @@ class Repairer {
      // Install new manifest
      status = env_->RenameFile(tmp, DescriptorFileName(dbname_, 1));
      if (status.ok()) {
-        status = SetCurrentFile(env_, dbname_, 1);
+        status = SetCurrentFile(env_, dbname_, 1, nullptr);
      } else {
        env_->DeleteFile(tmp);
      }
@@ -83,15 +83,17 @@ public:
                     unique_ptr<RandomAccessFile> && file, uint64_t file_size,
                     unique_ptr<TableReader>* table_reader);

-  Iterator* NewIterator(const ReadOptions&) override;
+  Iterator* NewIterator(const ReadOptions&, Arena* arena) override;

  Status Get(const ReadOptions&, const Slice& key, void* arg,
             bool (*handle_result)(void* arg, const ParsedInternalKey& k,
-                                   const Slice& v, bool),
+                                   const Slice& v),
             void (*mark_key_may_exist)(void*) = nullptr) override;

  uint64_t ApproximateOffsetOf(const Slice& key) override;

+  virtual size_t ApproximateMemoryUsage() const override { return 0; }
+
  void SetupForCompaction() override;

  std::shared_ptr<const TableProperties> GetTableProperties() const override;
@@ -218,8 +220,14 @@ std::shared_ptr<const TableProperties> SimpleTableReader::GetTableProperties()
  return rep_->table_properties;
 }

-Iterator* SimpleTableReader::NewIterator(const ReadOptions& options) {
-  return new SimpleTableIterator(this);
+Iterator* SimpleTableReader::NewIterator(const ReadOptions& options,
+                                         Arena* arena) {
+  if (arena == nullptr) {
+    return new SimpleTableIterator(this);
+  } else {
+    auto mem = arena->AllocateAligned(sizeof(SimpleTableIterator));
+    return new (mem) SimpleTableIterator(this);
+  }
 }

 Status SimpleTableReader::GetOffset(const Slice& target, uint64_t* offset) {
@@ -279,7 +287,7 @@ Status SimpleTableReader::GetOffset(const Slice& target, uint64_t* offset) {
 Status SimpleTableReader::Get(const ReadOptions& options, const Slice& k,
                              void* arg,
                              bool (*saver)(void*, const ParsedInternalKey&,
-                                            const Slice&, bool),
+                                            const Slice&),
                              void (*mark_key_may_exist)(void*)) {
  Status s;
  SimpleTableIterator* iter = new SimpleTableIterator(this);
@@ -289,7 +297,7 @@ Status SimpleTableReader::Get(const ReadOptions& options, const Slice& k,
      return Status::Corruption(Slice());
    }

-    if (!(*saver)(arg, parsed_key, iter->value(), true)) {
+    if (!(*saver)(arg, parsed_key, iter->value())) {
      break;
    }
  }
@@ -13,6 +13,7 @@
 #include "db/version_edit.h"

 #include "rocksdb/statistics.h"
+#include "table/iterator_wrapper.h"
 #include "table/table_reader.h"
 #include "util/coding.h"
 #include "util/stop_watch.h"
@@ -30,15 +31,15 @@ static void UnrefEntry(void* arg1, void* arg2) {
  cache->Release(h);
 }

-static Slice GetSliceForFileNumber(uint64_t* file_number) {
+static Slice GetSliceForFileNumber(const uint64_t* file_number) {
  return Slice(reinterpret_cast<const char*>(file_number),
               sizeof(*file_number));
 }

-TableCache::TableCache(const std::string& dbname, const Options* options,
+TableCache::TableCache(const Options* options,
                       const EnvOptions& storage_options, Cache* const cache)
    : env_(options->env),
-      dbname_(dbname),
+      db_paths_(options->db_paths),
      options_(options),
      storage_options_(storage_options),
      cache_(cache) {}
@@ -56,20 +57,18 @@ void TableCache::ReleaseHandle(Cache::Handle* handle) {

 Status TableCache::FindTable(const EnvOptions& toptions,
                             const InternalKeyComparator& internal_comparator,
-                             uint64_t file_number, uint64_t file_size,
-                             Cache::Handle** handle, bool* table_io,
+                             const FileDescriptor& fd, Cache::Handle** handle,
                             const bool no_io) {
  Status s;
-  Slice key = GetSliceForFileNumber(&file_number);
+  uint64_t number = fd.GetNumber();
+  Slice key = GetSliceForFileNumber(&number);
  *handle = cache_->Lookup(key);
  if (*handle == nullptr) {
    if (no_io) { // Dont do IO and return a not-found status
      return Status::Incomplete("Table not found in table_cache, no_io is set");
    }
-    if (table_io != nullptr) {
-      *table_io = true;    // we had to do IO from storage
-    }
-    std::string fname = TableFileName(dbname_, file_number);
+    std::string fname =
+        TableFileName(db_paths_, fd.GetNumber(), fd.GetPathId());
    unique_ptr<RandomAccessFile> file;
    unique_ptr<TableReader> table_reader;
    s = env_->NewRandomAccessFile(fname, &file, toptions);
@@ -80,8 +79,8 @@ Status TableCache::FindTable(const EnvOptions& toptions,
      }
      StopWatch sw(env_, options_->statistics.get(), TABLE_OPEN_IO_MICROS);
      s = options_->table_factory->NewTableReader(
-          *options_, toptions, internal_comparator, std::move(file), file_size,
-          &table_reader);
+          *options_, toptions, internal_comparator, std::move(file),
+          fd.GetFileSize(), &table_reader);
    }

    if (!s.ok()) {
@@ -100,25 +99,25 @@ Status TableCache::FindTable(const EnvOptions& toptions,
 Iterator* TableCache::NewIterator(const ReadOptions& options,
                                  const EnvOptions& toptions,
                                  const InternalKeyComparator& icomparator,
-                                  const FileMetaData& file_meta,
+                                  const FileDescriptor& fd,
                                  TableReader** table_reader_ptr,
-                                  bool for_compaction) {
+                                  bool for_compaction, Arena* arena) {
  if (table_reader_ptr != nullptr) {
    *table_reader_ptr = nullptr;
  }
-  TableReader* table_reader = file_meta.table_reader;
+  TableReader* table_reader = fd.table_reader;
  Cache::Handle* handle = nullptr;
  Status s;
  if (table_reader == nullptr) {
-    s = FindTable(toptions, icomparator, file_meta.number, file_meta.file_size,
-                  &handle, nullptr, options.read_tier == kBlockCacheTier);
+    s = FindTable(toptions, icomparator, fd, &handle,
+                  options.read_tier == kBlockCacheTier);
    if (!s.ok()) {
-      return NewErrorIterator(s);
+      return NewErrorIterator(s, arena);
    }
    table_reader = GetTableReaderFromHandle(handle);
  }

-  Iterator* result = table_reader->NewIterator(options);
+  Iterator* result = table_reader->NewIterator(options, arena);
  if (handle != nullptr) {
    result->RegisterCleanup(&UnrefEntry, cache_, handle);
  }
@@ -135,16 +134,15 @@ Iterator* TableCache::NewIterator(const ReadOptions& options,

 Status TableCache::Get(const ReadOptions& options,
                       const InternalKeyComparator& internal_comparator,
-                       const FileMetaData& file_meta, const Slice& k, void* arg,
+                       const FileDescriptor& fd, const Slice& k, void* arg,
                       bool (*saver)(void*, const ParsedInternalKey&,
-                                     const Slice&, bool),
-                       bool* table_io, void (*mark_key_may_exist)(void*)) {
-  TableReader* t = file_meta.table_reader;
+                                     const Slice&),
+                       void (*mark_key_may_exist)(void*)) {
+  TableReader* t = fd.table_reader;
  Status s;
  Cache::Handle* handle = nullptr;
  if (!t) {
-    s = FindTable(storage_options_, internal_comparator, file_meta.number,
-                  file_meta.file_size, &handle, table_io,
+    s = FindTable(storage_options_, internal_comparator, fd, &handle,
                  options.read_tier == kBlockCacheTier);
    if (s.ok()) {
      t = GetTableReaderFromHandle(handle);
@@ -164,11 +162,10 @@ Status TableCache::Get(const ReadOptions& options,
 }
 Status TableCache::GetTableProperties(
    const EnvOptions& toptions,
-    const InternalKeyComparator& internal_comparator,
-    const FileMetaData& file_meta,
+    const InternalKeyComparator& internal_comparator, const FileDescriptor& fd,
    std::shared_ptr<const TableProperties>* properties, bool no_io) {
  Status s;
-  auto table_reader = file_meta.table_reader;
+  auto table_reader = fd.table_reader;
  // table already been pre-loaded?
  if (table_reader) {
    *properties = table_reader->GetTableProperties();
@@ -176,10 +173,8 @@ Status TableCache::GetTableProperties(
    return s;
  }

-  bool table_io;
  Cache::Handle* table_handle = nullptr;
-  s = FindTable(toptions, internal_comparator, file_meta.number,
-                file_meta.file_size, &table_handle, &table_io, no_io);
+  s = FindTable(toptions, internal_comparator, fd, &table_handle, no_io);
  if (!s.ok()) {
    return s;
  }
@@ -190,6 +185,29 @@ Status TableCache::GetTableProperties(
  return s;
 }

+size_t TableCache::GetMemoryUsageByTableReader(
+    const EnvOptions& toptions,
+    const InternalKeyComparator& internal_comparator,
+    const FileDescriptor& fd) {
+  Status s;
+  auto table_reader = fd.table_reader;
+  // table already been pre-loaded?
+  if (table_reader) {
+    return table_reader->ApproximateMemoryUsage();
+  }
+
+  Cache::Handle* table_handle = nullptr;
+  s = FindTable(toptions, internal_comparator, fd, &table_handle, true);
+  if (!s.ok()) {
+    return 0;
+  }
+  assert(table_handle);
+  auto table = GetTableReaderFromHandle(table_handle);
+  auto ret = table->ApproximateMemoryUsage();
+  ReleaseHandle(table_handle);
+  return ret;
+}
+
 void TableCache::Evict(Cache* cache, uint64_t file_number) {
  cache->Erase(GetSliceForFileNumber(&file_number));
 }
@@ -11,6 +11,7 @@

 #pragma once
 #include <string>
+#include <vector>
 #include <stdint.h>

 #include "db/dbformat.h"
@@ -23,14 +24,13 @@
 namespace rocksdb {

 class Env;
-struct FileMetaData;
+class Arena;
+struct FileDescriptor;

-// TODO(sdong): try to come up with a better API to pass the file information
-//              other than simply passing FileMetaData.
 class TableCache {
 public:
-  TableCache(const std::string& dbname, const Options* options,
-             const EnvOptions& storage_options, Cache* cache);
+  TableCache(const Options* options, const EnvOptions& storage_options,
+             Cache* cache);
  ~TableCache();

  // Return an iterator for the specified file number (the corresponding
@@ -42,19 +42,19 @@ class TableCache {
  // returned iterator is live.
  Iterator* NewIterator(const ReadOptions& options, const EnvOptions& toptions,
                        const InternalKeyComparator& internal_comparator,
-                        const FileMetaData& file_meta,
+                        const FileDescriptor& file_fd,
                        TableReader** table_reader_ptr = nullptr,
-                        bool for_compaction = false);
+                        bool for_compaction = false, Arena* arena = nullptr);

  // If a seek to internal key "k" in specified file finds an entry,
  // call (*handle_result)(arg, found_key, found_value) repeatedly until
  // it returns false.
  Status Get(const ReadOptions& options,
             const InternalKeyComparator& internal_comparator,
-             const FileMetaData& file_meta, const Slice& k, void* arg,
+             const FileDescriptor& file_fd, const Slice& k, void* arg,
             bool (*handle_result)(void*, const ParsedInternalKey&,
-                                   const Slice&, bool),
-             bool* table_io, void (*mark_key_may_exist)(void*) = nullptr);
+                                   const Slice&),
+             void (*mark_key_may_exist)(void*) = nullptr);

  // Evict any entry for the specified file number
  static void Evict(Cache* cache, uint64_t file_number);
@@ -62,8 +62,8 @@ class TableCache {
  // Find table reader
  Status FindTable(const EnvOptions& toptions,
                   const InternalKeyComparator& internal_comparator,
-                   uint64_t file_number, uint64_t file_size, Cache::Handle**,
-                   bool* table_io = nullptr, const bool no_io = false);
+                   const FileDescriptor& file_fd, Cache::Handle**,
+                   const bool no_io = false);

  // Get TableReader from a cache handle.
  TableReader* GetTableReaderFromHandle(Cache::Handle* handle);
@@ -76,16 +76,23 @@ class TableCache {
  //            we set `no_io` to be true.
  Status GetTableProperties(const EnvOptions& toptions,
                            const InternalKeyComparator& internal_comparator,
-                            const FileMetaData& file_meta,
+                            const FileDescriptor& file_meta,
                            std::shared_ptr<const TableProperties>* properties,
                            bool no_io = false);

+  // Return total memory usage of the table reader of the file.
+  // 0 of table reader of the file is not loaded.
+  size_t GetMemoryUsageByTableReader(
+      const EnvOptions& toptions,
+      const InternalKeyComparator& internal_comparator,
+      const FileDescriptor& fd);
+
  // Release the handle from a cache
  void ReleaseHandle(Cache::Handle* handle);

 private:
  Env* const env_;
-  const std::string dbname_;
+  const std::vector<DbPath> db_paths_;
  const Options* options_;
  const EnvOptions& storage_options_;
  Cache* const cache_;
@@ -36,6 +36,18 @@ class InternalKeyPropertiesCollector : public TablePropertiesCollector {
  uint64_t deleted_keys_ = 0;
 };

+class InternalKeyPropertiesCollectorFactory
+    : public TablePropertiesCollectorFactory {
+ public:
+  virtual TablePropertiesCollector* CreateTablePropertiesCollector() {
+    return new InternalKeyPropertiesCollector();
+  }
+
+  virtual const char* Name() const override {
+    return "InternalKeyPropertiesCollectorFactory";
+  }
+};
+
 // When rocksdb creates a new table, it will encode all "user keys" into
 // "internal keys", which contains meta information of a given entry.
 //
@@ -43,19 +55,11 @@ class InternalKeyPropertiesCollector : public TablePropertiesCollector {
 // invoked.
 class UserKeyTablePropertiesCollector : public TablePropertiesCollector {
 public:
-  explicit UserKeyTablePropertiesCollector(
-      TablePropertiesCollector* collector) :
-      UserKeyTablePropertiesCollector(
-        std::shared_ptr<TablePropertiesCollector>(collector)
-    ) {
-  }
+  // transfer of ownership
+  explicit UserKeyTablePropertiesCollector(TablePropertiesCollector* collector)
+      : collector_(collector) {}

-  explicit UserKeyTablePropertiesCollector(
-      std::shared_ptr<TablePropertiesCollector> collector) :
-      collector_(collector) {
-  }
-
-  virtual ~UserKeyTablePropertiesCollector() { }
+  virtual ~UserKeyTablePropertiesCollector() {}

  virtual Status Add(const Slice& key, const Slice& value) override;

@@ -66,7 +70,26 @@ class UserKeyTablePropertiesCollector : public TablePropertiesCollector {
  UserCollectedProperties GetReadableProperties() const override;

 protected:
-  std::shared_ptr<TablePropertiesCollector> collector_;
+  std::unique_ptr<TablePropertiesCollector> collector_;
+};
+
+class UserKeyTablePropertiesCollectorFactory
+    : public TablePropertiesCollectorFactory {
+ public:
+  explicit UserKeyTablePropertiesCollectorFactory(
+      std::shared_ptr<TablePropertiesCollectorFactory> user_collector_factory)
+      : user_collector_factory_(user_collector_factory) {}
+  virtual TablePropertiesCollector* CreateTablePropertiesCollector() {
+    return new UserKeyTablePropertiesCollector(
+        user_collector_factory_->CreateTablePropertiesCollector());
+  }
+
+  virtual const char* Name() const override {
+    return user_collector_factory_->Name();
+  }
+
+ private:
+  std::shared_ptr<TablePropertiesCollectorFactory> user_collector_factory_;
 };

 }  // namespace rocksdb
@@ -121,11 +121,18 @@ class RegularKeysStartWithA: public TablePropertiesCollector {
    return UserCollectedProperties{};
  }

-
 private:
  uint32_t count_ = 0;
 };

+class RegularKeysStartWithAFactory : public TablePropertiesCollectorFactory {
+ public:
+  virtual TablePropertiesCollector* CreateTablePropertiesCollector() {
+    return new RegularKeysStartWithA();
+  }
+  const char* Name() const { return "RegularKeysStartWithA"; }
+};
+
 extern uint64_t kBlockBasedTableMagicNumber;
 extern uint64_t kPlainTableMagicNumber;
 namespace {
@@ -188,14 +195,14 @@ TEST(TablePropertiesTest, CustomizedTablePropertiesCollector) {
  // for block based table
  for (bool encode_as_internal : { true, false }) {
    Options options;
-    auto collector = new RegularKeysStartWithA();
+    std::shared_ptr<TablePropertiesCollectorFactory> collector_factory(
+        new RegularKeysStartWithAFactory());
    if (encode_as_internal) {
-      options.table_properties_collectors = {
-        std::make_shared<UserKeyTablePropertiesCollector>(collector)
-      };
+      options.table_properties_collector_factories.emplace_back(
+          new UserKeyTablePropertiesCollectorFactory(collector_factory));
    } else {
-      options.table_properties_collectors.resize(1);
-      options.table_properties_collectors[0].reset(collector);
+      options.table_properties_collector_factories.resize(1);
+      options.table_properties_collector_factories[0] = collector_factory;
    }
    test::PlainInternalKeyComparator ikc(options.comparator);
    TestCustomizedTablePropertiesCollector(kBlockBasedTableMagicNumber,
@@ -204,10 +211,16 @@ TEST(TablePropertiesTest, CustomizedTablePropertiesCollector) {

  // test plain table
  Options options;
-  options.table_properties_collectors.push_back(
-      std::make_shared<RegularKeysStartWithA>()
-  );
-  options.table_factory = std::make_shared<PlainTableFactory>(8, 8, 0);
+  options.table_properties_collector_factories.emplace_back(
+      new RegularKeysStartWithAFactory());
+
+  PlainTableOptions plain_table_options;
+  plain_table_options.user_key_len = 8;
+  plain_table_options.bloom_bits_per_key = 8;
+  plain_table_options.hash_table_ratio = 0;
+
+  options.table_factory =
+      std::make_shared<PlainTableFactory>(plain_table_options);
  test::PlainInternalKeyComparator ikc(options.comparator);
  TestCustomizedTablePropertiesCollector(kPlainTableMagicNumber, true, options,
                                         ikc);
@@ -235,9 +248,8 @@ void TestInternalKeyPropertiesCollector(

  options.table_factory = table_factory;
  if (sanitized) {
-    options.table_properties_collectors = {
-      std::make_shared<RegularKeysStartWithA>()
-    };
+    options.table_properties_collector_factories.emplace_back(
+        new RegularKeysStartWithAFactory());
    // with sanitization, even regular properties collector will be able to
    // handle internal keys.
    auto comparator = options.comparator;
@@ -249,40 +261,36 @@ void TestInternalKeyPropertiesCollector(
                              options);
    options.comparator = comparator;
  } else {
-    options.table_properties_collectors = {
-      std::make_shared<InternalKeyPropertiesCollector>()
-    };
+    options.table_properties_collector_factories = {
+        std::make_shared<InternalKeyPropertiesCollectorFactory>()};
  }

-  MakeBuilder(options, pikc, &writable, &builder);
-  for (const auto& k : keys) {
-    builder->Add(k.Encode(), "val");
-  }
+  for (int iter = 0; iter < 2; ++iter) {
+    MakeBuilder(options, pikc, &writable, &builder);
+    for (const auto& k : keys) {
+      builder->Add(k.Encode(), "val");
+    }

-  ASSERT_OK(builder->Finish());
+    ASSERT_OK(builder->Finish());

-  FakeRandomeAccessFile readable(writable->contents());
-  TableProperties* props;
-  Status s = ReadTableProperties(
-      &readable,
-      writable->contents().size(),
-      magic_number,
-      Env::Default(),
-      nullptr,
-      &props
-  );
-  ASSERT_OK(s);
+    FakeRandomeAccessFile readable(writable->contents());
+    TableProperties* props;
+    Status s =
+        ReadTableProperties(&readable, writable->contents().size(),
+                            magic_number, Env::Default(), nullptr, &props);
+    ASSERT_OK(s);

-  std::unique_ptr<TableProperties> props_guard(props);
-  auto user_collected = props->user_collected_properties;
-  uint64_t deleted = GetDeletedKeys(user_collected);
-  ASSERT_EQ(4u, deleted);
+    std::unique_ptr<TableProperties> props_guard(props);
+    auto user_collected = props->user_collected_properties;
+    uint64_t deleted = GetDeletedKeys(user_collected);
+    ASSERT_EQ(4u, deleted);

-  if (sanitized) {
-    uint32_t starts_with_A = 0;
-    Slice key(user_collected.at("Count"));
-    ASSERT_TRUE(GetVarint32(&key, &starts_with_A));
-    ASSERT_EQ(1u, starts_with_A);
+    if (sanitized) {
+      uint32_t starts_with_A = 0;
+      Slice key(user_collected.at("Count"));
+      ASSERT_TRUE(GetVarint32(&key, &starts_with_A));
+      ASSERT_EQ(1u, starts_with_A);
+    }
  }
 }
 }  // namespace
@@ -298,11 +306,15 @@ TEST(TablePropertiesTest, InternalKeyPropertiesCollector) {
      true /* not sanitize */,
      std::make_shared<BlockBasedTableFactory>()
  );
+
+  PlainTableOptions plain_table_options;
+  plain_table_options.user_key_len = 8;
+  plain_table_options.bloom_bits_per_key = 8;
+  plain_table_options.hash_table_ratio = 0;
+
  TestInternalKeyPropertiesCollector(
-      kPlainTableMagicNumber,
-      false /* not sanitize */,
-      std::make_shared<PlainTableFactory>(8, 8, 0)
-  );
+      kPlainTableMagicNumber, false /* not sanitize */,
+      std::make_shared<PlainTableFactory>(plain_table_options));
 }

 }  // namespace rocksdb
@@ -93,6 +93,7 @@ void TransactionLogIteratorImpl::SeekToStartSequence(
  Status s = OpenLogReader(files_->at(startFileIndex).get());
  if (!s.ok()) {
    currentStatus_ = s;
+    reporter_.Info(currentStatus_.ToString().c_str());
    return;
  }
  while (RestrictedRead(&record, &scratch)) {
@@ -18,25 +18,30 @@ namespace rocksdb {
 // Tag numbers for serialized VersionEdit.  These numbers are written to
 // disk and should not be changed.
 enum Tag {
-  kComparator           = 1,
-  kLogNumber            = 2,
-  kNextFileNumber       = 3,
-  kLastSequence         = 4,
-  kCompactPointer       = 5,
-  kDeletedFile          = 6,
-  kNewFile              = 7,
+  kComparator = 1,
+  kLogNumber = 2,
+  kNextFileNumber = 3,
+  kLastSequence = 4,
+  kCompactPointer = 5,
+  kDeletedFile = 6,
+  kNewFile = 7,
  // 8 was used for large value refs
-  kPrevLogNumber        = 9,
+  kPrevLogNumber = 9,

  // these are new formats divergent from open source leveldb
-  kNewFile2             = 100,  // store smallest & largest seqno
-
-  kColumnFamily         = 200,  // specify column family for version edit
-  kColumnFamilyAdd      = 201,
-  kColumnFamilyDrop     = 202,
-  kMaxColumnFamily      = 203,
+  kNewFile2 = 100,
+  kNewFile3 = 102,
+  kColumnFamily = 200,  // specify column family for version edit
+  kColumnFamilyAdd = 201,
+  kColumnFamilyDrop = 202,
+  kMaxColumnFamily = 203,
 };

+uint64_t PackFileNumberAndPathId(uint64_t number, uint64_t path_id) {
+  assert(number <= kFileNumberMask);
+  return number | (path_id * (kFileNumberMask + 1));
+}
+
 void VersionEdit::Clear() {
  comparator_.clear();
  max_level_ = 0;
@@ -93,10 +98,19 @@ void VersionEdit::EncodeTo(std::string* dst) const {

  for (size_t i = 0; i < new_files_.size(); i++) {
    const FileMetaData& f = new_files_[i].second;
-    PutVarint32(dst, kNewFile2);
+    if (f.fd.GetPathId() == 0) {
+      // Use older format to make sure user can roll back the build if they
+      // don't config multiple DB paths.
+      PutVarint32(dst, kNewFile2);
+    } else {
+      PutVarint32(dst, kNewFile3);
+    }
    PutVarint32(dst, new_files_[i].first);  // level
-    PutVarint64(dst, f.number);
-    PutVarint64(dst, f.file_size);
+    PutVarint64(dst, f.fd.GetNumber());
+    if (f.fd.GetPathId() != 0) {
+      PutVarint32(dst, f.fd.GetPathId());
+    }
+    PutVarint64(dst, f.fd.GetFileSize());
    PutLengthPrefixedSlice(dst, f.smallest.Encode());
    PutLengthPrefixedSlice(dst, f.largest.Encode());
    PutVarint64(dst, f.smallest_seqno);
@@ -123,7 +137,7 @@ static bool GetInternalKey(Slice* input, InternalKey* dst) {
  Slice str;
  if (GetLengthPrefixedSlice(input, &str)) {
    dst->DecodeFrom(str);
-    return true;
+    return dst->Valid();
  } else {
    return false;
  }
@@ -230,12 +244,14 @@ Status VersionEdit::DecodeFrom(const Slice& src) {
        }
        break;

-      case kNewFile:
-        if (GetLevel(&input, &level, &msg) &&
-            GetVarint64(&input, &f.number) &&
-            GetVarint64(&input, &f.file_size) &&
+      case kNewFile: {
+        uint64_t number;
+        uint64_t file_size;
+        if (GetLevel(&input, &level, &msg) && GetVarint64(&input, &number) &&
+            GetVarint64(&input, &file_size) &&
            GetInternalKey(&input, &f.smallest) &&
            GetInternalKey(&input, &f.largest)) {
+          f.fd = FileDescriptor(number, 0, file_size);
          new_files_.push_back(std::make_pair(level, f));
        } else {
          if (!msg) {
@@ -243,15 +259,17 @@ Status VersionEdit::DecodeFrom(const Slice& src) {
          }
        }
        break;
-
-      case kNewFile2:
-        if (GetLevel(&input, &level, &msg) &&
-            GetVarint64(&input, &f.number) &&
-            GetVarint64(&input, &f.file_size) &&
+      }
+      case kNewFile2: {
+        uint64_t number;
+        uint64_t file_size;
+        if (GetLevel(&input, &level, &msg) && GetVarint64(&input, &number) &&
+            GetVarint64(&input, &file_size) &&
            GetInternalKey(&input, &f.smallest) &&
            GetInternalKey(&input, &f.largest) &&
            GetVarint64(&input, &f.smallest_seqno) &&
-            GetVarint64(&input, &f.largest_seqno) ) {
+            GetVarint64(&input, &f.largest_seqno)) {
+          f.fd = FileDescriptor(number, 0, file_size);
          new_files_.push_back(std::make_pair(level, f));
        } else {
          if (!msg) {
@@ -259,6 +277,27 @@ Status VersionEdit::DecodeFrom(const Slice& src) {
          }
        }
        break;
+      }
+
+      case kNewFile3: {
+        uint64_t number;
+        uint32_t path_id;
+        uint64_t file_size;
+        if (GetLevel(&input, &level, &msg) && GetVarint64(&input, &number) &&
+            GetVarint32(&input, &path_id) && GetVarint64(&input, &file_size) &&
+            GetInternalKey(&input, &f.smallest) &&
+            GetInternalKey(&input, &f.largest) &&
+            GetVarint64(&input, &f.smallest_seqno) &&
+            GetVarint64(&input, &f.largest_seqno)) {
+          f.fd = FileDescriptor(number, path_id, file_size);
+          new_files_.push_back(std::make_pair(level, f));
+        } else {
+          if (!msg) {
+            msg = "new-file2 entry";
+          }
+        }
+        break;
+      }

      case kColumnFamily:
        if (!GetVarint32(&input, &column_family_)) {
@@ -336,9 +375,9 @@ std::string VersionEdit::DebugString(bool hex_key) const {
    r.append("\n  AddFile: ");
    AppendNumberTo(&r, new_files_[i].first);
    r.append(" ");
-    AppendNumberTo(&r, f.number);
+    AppendNumberTo(&r, f.fd.GetNumber());
    r.append(" ");
-    AppendNumberTo(&r, f.file_size);
+    AppendNumberTo(&r, f.fd.GetFileSize());
    r.append(" ");
    r.append(f.smallest.DebugString(hex_key));
    r.append(" .. ");
@@ -14,36 +14,115 @@
 #include <string>
 #include "rocksdb/cache.h"
 #include "db/dbformat.h"
+#include "util/arena.h"
+#include "util/autovector.h"

 namespace rocksdb {

 class VersionSet;

+const uint64_t kFileNumberMask = 0x3FFFFFFFFFFFFFFF;
+
+extern uint64_t PackFileNumberAndPathId(uint64_t number, uint64_t path_id);
+
+// A copyable structure contains information needed to read data from an SST
+// file. It can contains a pointer to a table reader opened for the file, or
+// file number and size, which can be used to create a new table reader for it.
+// The behavior is undefined when a copied of the structure is used when the
+// file is not in any live version any more.
+struct FileDescriptor {
+  // Table reader in table_reader_handle
+  TableReader* table_reader;
+  uint64_t packed_number_and_path_id;
+  uint64_t file_size;  // File size in bytes
+
+  FileDescriptor() : FileDescriptor(0, 0, 0) {}
+
+  FileDescriptor(uint64_t number, uint32_t path_id, uint64_t file_size)
+      : table_reader(nullptr),
+        packed_number_and_path_id(PackFileNumberAndPathId(number, path_id)),
+        file_size(file_size) {}
+
+  FileDescriptor& operator=(const FileDescriptor& fd) {
+    table_reader = fd.table_reader;
+    packed_number_and_path_id = fd.packed_number_and_path_id;
+    file_size = fd.file_size;
+    return *this;
+  }
+
+  uint64_t GetNumber() const {
+    return packed_number_and_path_id & kFileNumberMask;
+  }
+  uint32_t GetPathId() const {
+    return packed_number_and_path_id / (kFileNumberMask + 1);
+  }
+  uint64_t GetFileSize() const { return file_size; }
+};
+
 struct FileMetaData {
  int refs;
-  int allowed_seeks;          // Seeks allowed until compaction
-  uint64_t number;
-  uint64_t file_size;         // File size in bytes
-  InternalKey smallest;       // Smallest internal key served by table
-  InternalKey largest;        // Largest internal key served by table
-  bool being_compacted;       // Is this file undergoing compaction?
-  SequenceNumber smallest_seqno;// The smallest seqno in this file
-  SequenceNumber largest_seqno; // The largest seqno in this file
+  FileDescriptor fd;
+  InternalKey smallest;            // Smallest internal key served by table
+  InternalKey largest;             // Largest internal key served by table
+  bool being_compacted;            // Is this file undergoing compaction?
+  SequenceNumber smallest_seqno;   // The smallest seqno in this file
+  SequenceNumber largest_seqno;    // The largest seqno in this file

  // Needs to be disposed when refs becomes 0.
  Cache::Handle* table_reader_handle;
-  // Table reader in table_reader_handle
-  TableReader* table_reader;

-  FileMetaData(uint64_t number, uint64_t file_size)
+  // Stats for compensating deletion entries during compaction
+
+  // File size compensated by deletion entry.
+  // This is updated in Version::UpdateTemporaryStats() first time when the
+  // file is created or loaded.  After it is updated, it is immutable.
+  uint64_t compensated_file_size;
+  uint64_t num_entries;            // the number of entries.
+  uint64_t num_deletions;          // the number of deletion entries.
+  uint64_t raw_key_size;           // total uncompressed key size.
+  uint64_t raw_value_size;         // total uncompressed value size.
+
+  FileMetaData()
      : refs(0),
-        allowed_seeks(1 << 30),
-        number(number),
-        file_size(file_size),
        being_compacted(false),
        table_reader_handle(nullptr),
-        table_reader(nullptr) {}
-  FileMetaData() : FileMetaData(0, 0) {}
+        compensated_file_size(0),
+        num_entries(0),
+        num_deletions(0),
+        raw_key_size(0),
+        raw_value_size(0) {}
+};
+
+// A compressed copy of file meta data that just contain
+// smallest and largest key's slice
+struct FdWithKeyRange {
+  FileDescriptor fd;
+  Slice smallest_key;    // slice that contain smallest key
+  Slice largest_key;     // slice that contain largest key
+
+  FdWithKeyRange()
+      : fd(),
+        smallest_key(),
+        largest_key() {
+  }
+
+  FdWithKeyRange(FileDescriptor fd,
+      Slice smallest_key, Slice largest_key)
+      : fd(fd),
+        smallest_key(smallest_key),
+        largest_key(largest_key) {
+  }
+};
+
+// Data structure to store an array of FdWithKeyRange in one level
+// Actual data is guaranteed to be stored closely
+struct FileLevel {
+  size_t num_files;
+  FdWithKeyRange* files;
+  FileLevel() {
+    num_files = 0;
+    files = nullptr;
+  }
 };

 class VersionEdit {
@@ -81,16 +160,13 @@ class VersionEdit {
  // Add the specified file at the specified number.
  // REQUIRES: This version has not been saved (see VersionSet::SaveTo)
  // REQUIRES: "smallest" and "largest" are smallest and largest keys in file
-  void AddFile(int level, uint64_t file,
-               uint64_t file_size,
-               const InternalKey& smallest,
-               const InternalKey& largest,
-               const SequenceNumber& smallest_seqno,
+  void AddFile(int level, uint64_t file, uint64_t file_size,
+               uint64_t file_path_id, const InternalKey& smallest,
+               const InternalKey& largest, const SequenceNumber& smallest_seqno,
               const SequenceNumber& largest_seqno) {
    assert(smallest_seqno <= largest_seqno);
    FileMetaData f;
-    f.number = file;
-    f.file_size = file_size;
+    f.fd = FileDescriptor(file, file_size, file_path_id);
    f.smallest = smallest;
    f.largest = largest;
    f.smallest_seqno = smallest_seqno;
@@ -140,6 +216,7 @@ class VersionEdit {

 private:
  friend class VersionSet;
+  friend class Version;

  typedef std::set< std::pair<int, uint64_t>> DeletedFileSet;

@@ -30,11 +30,10 @@ TEST(VersionEditTest, EncodeDecode) {
  VersionEdit edit;
  for (int i = 0; i < 4; i++) {
    TestEncodeDecode(edit);
-    edit.AddFile(3, kBig + 300 + i, kBig + 400 + i,
+    edit.AddFile(3, kBig + 300 + i, kBig + 400 + i, 0,
                 InternalKey("foo", kBig + 500 + i, kTypeValue),
                 InternalKey("zoo", kBig + 600 + i, kTypeDeletion),
-                 kBig + 500 + i,
-                 kBig + 600 + i);
+                 kBig + 500 + i, kBig + 600 + i);
    edit.DeleteFile(4, kBig + 700 + i);
  }

@@ -51,27 +51,36 @@ class MergeContext;
 class ColumnFamilyData;
 class ColumnFamilySet;
 class TableCache;
+class MergeIteratorBuilder;

-// Return the smallest index i such that files[i]->largest >= key.
-// Return files.size() if there is no such file.
-// REQUIRES: "files" contains a sorted list of non-overlapping files.
+// Return the smallest index i such that file_level.files[i]->largest >= key.
+// Return file_level.num_files if there is no such file.
+// REQUIRES: "file_level.files" contains a sorted list of
+// non-overlapping files.
 extern int FindFile(const InternalKeyComparator& icmp,
-                    const std::vector<FileMetaData*>& files,
+                    const FileLevel& file_level,
                    const Slice& key);

 // Returns true iff some file in "files" overlaps the user key range
 // [*smallest,*largest].
 // smallest==nullptr represents a key smaller than all keys in the DB.
 // largest==nullptr represents a key largest than all keys in the DB.
-// REQUIRES: If disjoint_sorted_files, files[] contains disjoint ranges
-//           in sorted order.
+// REQUIRES: If disjoint_sorted_files, file_level.files[]
+// contains disjoint ranges in sorted order.
 extern bool SomeFileOverlapsRange(
    const InternalKeyComparator& icmp,
    bool disjoint_sorted_files,
-    const std::vector<FileMetaData*>& files,
+    const FileLevel& file_level,
    const Slice* smallest_user_key,
    const Slice* largest_user_key);

+// Generate FileLevel from vector<FdWithKeyRange*>
+// Would copy smallest_key and largest_key data to sequential memory
+// arena: Arena used to allocate the memory
+extern void DoGenerateFileLevel(FileLevel* file_level,
+        const std::vector<FileMetaData*>& files,
+        Arena* arena);
+
 class Version {
 public:
  // Append to *iters a sequence of iterators that will
@@ -80,29 +89,30 @@ class Version {
  void AddIterators(const ReadOptions&, const EnvOptions& soptions,
                    std::vector<Iterator*>* iters);

+  void AddIterators(const ReadOptions&, const EnvOptions& soptions,
+                    MergeIteratorBuilder* merger_iter_builder);
+
  // Lookup the value for key.  If found, store it in *val and
-  // return OK.  Else return a non-OK status.  Fills *stats.
+  // return OK.  Else return a non-OK status.
  // Uses *operands to store merge_operator operations to apply later
  // REQUIRES: lock is not held
-  struct GetStats {
-    FileMetaData* seek_file;
-    int seek_file_level;
-  };
  void Get(const ReadOptions&, const LookupKey& key, std::string* val,
-           Status* status, MergeContext* merge_context, GetStats* stats,
+           Status* status, MergeContext* merge_context,
           bool* value_found = nullptr);

-  // Adds "stats" into the current state.  Returns true if a new
-  // compaction may need to be triggered, false otherwise.
-  // REQUIRES: lock is held
-  bool UpdateStats(const GetStats& stats);
-
  // Updates internal structures that keep track of compaction scores
  // We use compaction scores to figure out which compaction to do next
  // REQUIRES: If Version is not yet saved to current_, it can be called without
  // a lock. Once a version is saved to current_, call only with mutex held
  void ComputeCompactionScore(std::vector<uint64_t>& size_being_compacted);

+  // Generate file_levels_ from files_
+  void GenerateFileLevels();
+
+  // Update scores, pre-calculated variables. It needs to be called before
+  // applying the version to the version set.
+  void PrepareApply(std::vector<uint64_t>& size_being_compacted);
+
  // Reference count management (so Versions do not disappear out from
  // under live iterators)
  void Ref();
@@ -189,7 +199,7 @@ class Version {
  int64_t MaxNextLevelOverlappingBytes();

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

  // Return a human readable string that describes this version's contents.
  std::string DebugString(bool hex = false) const;
@@ -197,12 +207,35 @@ class Version {
  // Returns the version nuber of this version
  uint64_t GetVersionNumber() const { return version_number_; }

+  uint64_t GetAverageValueSize() const {
+    if (num_non_deletions_ == 0) {
+      return 0;
+    }
+    assert(total_raw_key_size_ + total_raw_value_size_ > 0);
+    assert(total_file_size_ > 0);
+    return total_raw_value_size_ / num_non_deletions_ * total_file_size_ /
+           (total_raw_key_size_ + total_raw_value_size_);
+  }
+
+  // REQUIRES: lock is held
+  // On success, "tp" will contains the table properties of the file
+  // specified in "file_meta".  If the file name of "file_meta" is
+  // known ahread, passing it by a non-null "fname" can save a
+  // file-name conversion.
+  Status GetTableProperties(std::shared_ptr<const TableProperties>* tp,
+                            const FileMetaData* file_meta,
+                            const std::string* fname = nullptr);
+
  // REQUIRES: lock is held
  // On success, *props will be populated with all SSTables' table properties.
  // The keys of `props` are the sst file name, the values of `props` are the
  // tables' propertis, represented as shared_ptr.
  Status GetPropertiesOfAllTables(TablePropertiesCollection* props);

+  uint64_t GetEstimatedActiveKeys();
+
+  size_t GetMemoryUsageByTableReaders();
+
  // used to sort files by size
  struct Fsize {
    int index;
@@ -217,6 +250,9 @@ class Version {
  friend class CompactionPicker;
  friend class LevelCompactionPicker;
  friend class UniversalCompactionPicker;
+  friend class FIFOCompactionPicker;
+  friend class ForwardIterator;
+  friend class InternalStats;

  class LevelFileNumIterator;
  class LevelFileIteratorState;
@@ -224,6 +260,18 @@ class Version {
  bool PrefixMayMatch(const ReadOptions& options, Iterator* level_iter,
                      const Slice& internal_prefix) const;

+  // Update num_non_empty_levels_.
+  void UpdateNumNonEmptyLevels();
+
+  // The helper function of UpdateTemporaryStats, which may fill the missing
+  // fields of file_mata from its associated TableProperties.
+  // Returns true if it does initialize FileMetaData.
+  bool MaybeInitializeFileMetaData(FileMetaData* file_meta);
+
+  // Update the temporary stats associated with the current version.
+  // This temporary stats will be used in compaction.
+  void UpdateTemporaryStats();
+
  // Sort all files for this version based on their file size and
  // record results in files_by_size_. The largest files are listed first.
  void UpdateFilesBySize();
@@ -233,13 +281,19 @@ class Version {
  const Comparator* user_comparator_;
  TableCache* table_cache_;
  const MergeOperator* merge_operator_;
+
+  autovector<FileLevel> file_levels_;   // A copy of list of files per level
  Logger* info_log_;
  Statistics* db_statistics_;
+  int num_levels_;              // Number of levels
+  int num_non_empty_levels_;    // Number of levels. Any level larger than it
+                                // is guaranteed to be empty.
+  FileIndexer file_indexer_;
  VersionSet* vset_;            // VersionSet to which this Version belongs
+  Arena arena_;                 // Used to allocate space for file_levels_
  Version* next_;               // Next version in linked list
  Version* prev_;               // Previous version in linked list
  int refs_;                    // Number of live refs to this version
-  int num_levels_;              // Number of levels

  // List of files per level, files in each level are arranged
  // in increasing order of keys
@@ -260,11 +314,7 @@ class Version {
  // that on a running system, we need to look at only the first
  // few largest files because a new version is created every few
  // seconds/minutes (because of concurrent compactions).
-  static const int number_of_files_to_sort_ = 50;
-
-  // Next file to compact based on seek stats.
-  FileMetaData* file_to_compact_;
-  int file_to_compact_level_;
+  static const size_t number_of_files_to_sort_ = 50;

  // Level that should be compacted next and its compaction score.
  // Score < 1 means compaction is not strictly needed.  These fields
@@ -281,7 +331,17 @@ class Version {
  uint64_t version_number_;

  Version(ColumnFamilyData* cfd, VersionSet* vset, uint64_t version_number = 0);
-  FileIndexer file_indexer_;
+
+  // total file size
+  uint64_t total_file_size_;
+  // the total size of all raw keys.
+  uint64_t total_raw_key_size_;
+  // the total size of all raw values.
+  uint64_t total_raw_value_size_;
+  // total number of non-deletion entries
+  uint64_t num_non_deletions_;
+  // total number of deletion entries
+  uint64_t num_deletions_;

  ~Version();

@@ -359,7 +419,7 @@ class VersionSet {
  // Arrange to reuse "file_number" unless a newer file number has
  // already been allocated.
  // REQUIRES: "file_number" was returned by a call to NewFileNumber().
-  void ReuseFileNumber(uint64_t file_number) {
+  void ReuseLogFileNumber(uint64_t file_number) {
    if (next_file_number_ == file_number + 1) {
      next_file_number_ = file_number;
    }
@@ -400,7 +460,7 @@ class VersionSet {
  Iterator* MakeInputIterator(Compaction* c);

  // Add all files listed in any live version to *live.
-  void AddLiveFiles(std::vector<uint64_t>* live_list);
+  void AddLiveFiles(std::vector<FileDescriptor>* live_list);

  // Return the approximate offset in the database of the data for
  // "key" as of version "v".
@@ -14,14 +14,15 @@

 namespace rocksdb {

-class FindFileTest {
+class GenerateFileLevelTest {
 public:
  std::vector<FileMetaData*> files_;
-  bool disjoint_sorted_files_;
+  FileLevel file_level_;
+  Arena arena_;

-  FindFileTest() : disjoint_sorted_files_(true) { }
+  GenerateFileLevelTest() { }

-  ~FindFileTest() {
+  ~GenerateFileLevelTest() {
    for (unsigned int i = 0; i < files_.size(); i++) {
      delete files_[i];
    }
@@ -31,29 +32,108 @@ class FindFileTest {
           SequenceNumber smallest_seq = 100,
           SequenceNumber largest_seq = 100) {
    FileMetaData* f = new FileMetaData;
-    f->number = files_.size() + 1;
+    f->fd = FileDescriptor(files_.size() + 1, 0, 0);
    f->smallest = InternalKey(smallest, smallest_seq, kTypeValue);
    f->largest = InternalKey(largest, largest_seq, kTypeValue);
    files_.push_back(f);
  }

+  int Compare() {
+    int diff = 0;
+    for (size_t i = 0; i < files_.size(); i++) {
+      if (file_level_.files[i].fd.GetNumber() != files_[i]->fd.GetNumber()) {
+        diff++;
+      }
+    }
+    return diff;
+  }
+};
+
+TEST(GenerateFileLevelTest, Empty) {
+  DoGenerateFileLevel(&file_level_, files_, &arena_);
+  ASSERT_EQ(0u, file_level_.num_files);
+  ASSERT_EQ(0, Compare());
+}
+
+TEST(GenerateFileLevelTest, Single) {
+  Add("p", "q");
+  DoGenerateFileLevel(&file_level_, files_, &arena_);
+  ASSERT_EQ(1u, file_level_.num_files);
+  ASSERT_EQ(0, Compare());
+}
+
+
+TEST(GenerateFileLevelTest, Multiple) {
+  Add("150", "200");
+  Add("200", "250");
+  Add("300", "350");
+  Add("400", "450");
+  DoGenerateFileLevel(&file_level_, files_, &arena_);
+  ASSERT_EQ(4u, file_level_.num_files);
+  ASSERT_EQ(0, Compare());
+}
+
+class FindLevelFileTest {
+ public:
+  FileLevel file_level_;
+  bool disjoint_sorted_files_;
+  Arena arena_;
+
+  FindLevelFileTest() : disjoint_sorted_files_(true) { }
+
+  ~FindLevelFileTest() {
+  }
+
+  void LevelFileInit(size_t num = 0) {
+    char* mem = arena_.AllocateAligned(num * sizeof(FdWithKeyRange));
+    file_level_.files = new (mem)FdWithKeyRange[num];
+    file_level_.num_files = 0;
+  }
+
+  void Add(const char* smallest, const char* largest,
+           SequenceNumber smallest_seq = 100,
+           SequenceNumber largest_seq = 100) {
+    InternalKey smallest_key = InternalKey(smallest, smallest_seq, kTypeValue);
+    InternalKey largest_key = InternalKey(largest, largest_seq, kTypeValue);
+
+    Slice smallest_slice = smallest_key.Encode();
+    Slice largest_slice = largest_key.Encode();
+
+    char* mem = arena_.AllocateAligned(
+        smallest_slice.size() + largest_slice.size());
+    memcpy(mem, smallest_slice.data(), smallest_slice.size());
+    memcpy(mem + smallest_slice.size(), largest_slice.data(),
+        largest_slice.size());
+
+    // add to file_level_
+    size_t num = file_level_.num_files;
+    auto& file = file_level_.files[num];
+    file.fd = FileDescriptor(num + 1, 0, 0);
+    file.smallest_key = Slice(mem, smallest_slice.size());
+    file.largest_key = Slice(mem + smallest_slice.size(),
+        largest_slice.size());
+    file_level_.num_files++;
+  }
+
  int Find(const char* key) {
    InternalKey target(key, 100, kTypeValue);
    InternalKeyComparator cmp(BytewiseComparator());
-    return FindFile(cmp, files_, target.Encode());
+    return FindFile(cmp, file_level_, target.Encode());
  }

  bool Overlaps(const char* smallest, const char* largest) {
    InternalKeyComparator cmp(BytewiseComparator());
    Slice s(smallest != nullptr ? smallest : "");
    Slice l(largest != nullptr ? largest : "");
-    return SomeFileOverlapsRange(cmp, disjoint_sorted_files_, files_,
+    return SomeFileOverlapsRange(cmp, disjoint_sorted_files_, file_level_,
                                 (smallest != nullptr ? &s : nullptr),
                                 (largest != nullptr ? &l : nullptr));
  }
 };

-TEST(FindFileTest, Empty) {
+TEST(FindLevelFileTest, LevelEmpty) {
+  LevelFileInit(0);
+
  ASSERT_EQ(0, Find("foo"));
  ASSERT_TRUE(! Overlaps("a", "z"));
  ASSERT_TRUE(! Overlaps(nullptr, "z"));
@@ -61,7 +141,9 @@ TEST(FindFileTest, Empty) {
  ASSERT_TRUE(! Overlaps(nullptr, nullptr));
 }

-TEST(FindFileTest, Single) {
+TEST(FindLevelFileTest, LevelSingle) {
+  LevelFileInit(1);
+
  Add("p", "q");
  ASSERT_EQ(0, Find("a"));
  ASSERT_EQ(0, Find("p"));
@@ -91,8 +173,9 @@ TEST(FindFileTest, Single) {
  ASSERT_TRUE(Overlaps(nullptr, nullptr));
 }

+TEST(FindLevelFileTest, LevelMultiple) {
+  LevelFileInit(4);

-TEST(FindFileTest, Multiple) {
  Add("150", "200");
  Add("200", "250");
  Add("300", "350");
@@ -130,7 +213,9 @@ TEST(FindFileTest, Multiple) {
  ASSERT_TRUE(Overlaps("450", "500"));
 }

-TEST(FindFileTest, MultipleNullBoundaries) {
+TEST(FindLevelFileTest, LevelMultipleNullBoundaries) {
+  LevelFileInit(4);
+
  Add("150", "200");
  Add("200", "250");
  Add("300", "350");
@@ -150,7 +235,9 @@ TEST(FindFileTest, MultipleNullBoundaries) {
  ASSERT_TRUE(Overlaps("450", nullptr));
 }

-TEST(FindFileTest, OverlapSequenceChecks) {
+TEST(FindLevelFileTest, LevelOverlapSequenceChecks) {
+  LevelFileInit(1);
+
  Add("200", "200", 5000, 3000);
  ASSERT_TRUE(! Overlaps("199", "199"));
  ASSERT_TRUE(! Overlaps("201", "300"));
@@ -159,7 +246,9 @@ TEST(FindFileTest, OverlapSequenceChecks) {
  ASSERT_TRUE(Overlaps("200", "210"));
 }

-TEST(FindFileTest, OverlappingFiles) {
+TEST(FindLevelFileTest, LevelOverlappingFiles) {
+  LevelFileInit(2);
+
  Add("150", "600");
  Add("400", "500");
  disjoint_sorted_files_ = false;
@@ -236,6 +236,23 @@ void WriteBatch::Delete(ColumnFamilyHandle* column_family, const Slice& key) {
  WriteBatchInternal::Delete(this, GetColumnFamilyID(column_family), key);
 }

+void WriteBatchInternal::Delete(WriteBatch* b, uint32_t column_family_id,
+                                const SliceParts& key) {
+  WriteBatchInternal::SetCount(b, WriteBatchInternal::Count(b) + 1);
+  if (column_family_id == 0) {
+    b->rep_.push_back(static_cast<char>(kTypeDeletion));
+  } else {
+    b->rep_.push_back(static_cast<char>(kTypeColumnFamilyDeletion));
+    PutVarint32(&b->rep_, column_family_id);
+  }
+  PutLengthPrefixedSliceParts(&b->rep_, key);
+}
+
+void WriteBatch::Delete(ColumnFamilyHandle* column_family,
+                        const SliceParts& key) {
+  WriteBatchInternal::Delete(this, GetColumnFamilyID(column_family), key);
+}
+
 void WriteBatchInternal::Merge(WriteBatch* b, uint32_t column_family_id,
                               const Slice& key, const Slice& value) {
  WriteBatchInternal::SetCount(b, WriteBatchInternal::Count(b) + 1);
@@ -419,8 +436,8 @@ class MemTableInserter : public WriteBatch::Handler {
          // Failed to merge!
        RecordTick(options->statistics.get(), NUMBER_MERGE_FAILURES);

-          // Store the delta in memtable
-          perform_merge = false;
+        // Store the delta in memtable
+        perform_merge = false;
      } else {
        // 3) Add value to memtable
        mem->Add(sequence_, kTypeValue, key, new_value);
@@ -71,6 +71,9 @@ class WriteBatchInternal {
  static void Put(WriteBatch* batch, uint32_t column_family_id,
                  const SliceParts& key, const SliceParts& value);

+  static void Delete(WriteBatch* batch, uint32_t column_family_id,
+                     const SliceParts& key);
+
  static void Delete(WriteBatch* batch, uint32_t column_family_id,
                     const Slice& key);

@@ -642,10 +642,6 @@ Default:1, i.e. pick maxfilesize amount of data as the source of a compaction.
 <li> <code>Options::max_grandparent_overlap_factor</code> -   Control maximum bytes of overlaps in grandparent (i.e., level+2) before we
 stop building a single file in a level->level+1 compaction.
 <p>
-<li> <code>Options::disable_seek_compaction</code> -  Disable compaction triggered by seek.
-With bloomfilter and fast storage, a miss on one level is very cheap if the file handle is cached in table cache
-(which is true if max_open_files is large).
-<p>
 <li> <code>Options::max_background_compactions</code> - Maximum number of concurrent background jobs, submitted to
 the default LOW priority thread pool
 </ul>
@@ -0,0 +1,2 @@
+column_families_example
+simple_example
@@ -0,0 +1,9 @@
+include ../build_config.mk
+
+all: simple_example column_families_example
+
+simple_example: simple_example.cc
+	$(CXX) $(CXXFLAGS) $@.cc -o$@ ../librocksdb.a -I../include -O2 -std=c++11 $(PLATFORM_LDFLAGS) $(PLATFORM_CXXFLAGS) $(EXEC_LDFLAGS)
+
+column_families_example: column_families_example.cc
+	$(CXX) $(CXXFLAGS) $@.cc -o$@ ../librocksdb.a -I../include -O2 -std=c++11 $(PLATFORM_LDFLAGS) $(PLATFORM_CXXFLAGS) $(EXEC_LDFLAGS)
@@ -0,0 +1 @@
+Compile RocksDB first by executing `make static_lib` in parent dir
@@ -0,0 +1,72 @@
+// Copyright (c) 2013, Facebook, Inc.  All rights reserved.
+// This source code is licensed under the BSD-style license found in the
+// LICENSE file in the root directory of this source tree. An additional grant
+// of patent rights can be found in the PATENTS file in the same directory.
+#include <cstdio>
+#include <string>
+#include <vector>
+
+#include "rocksdb/db.h"
+#include "rocksdb/slice.h"
+#include "rocksdb/options.h"
+
+using namespace rocksdb;
+
+std::string kDBPath = "/tmp/rocksdb_column_families_example";
+
+int main() {
+  // open DB
+  Options options;
+  options.create_if_missing = true;
+  DB* db;
+  Status s = DB::Open(options, kDBPath, &db);
+  assert(s.ok());
+
+  // create column family
+  ColumnFamilyHandle* cf;
+  s = db->CreateColumnFamily(ColumnFamilyOptions(), "new_cf", &cf);
+  assert(s.ok());
+
+  // close DB
+  delete cf;
+  delete db;
+
+  // open DB with two column families
+  std::vector<ColumnFamilyDescriptor> column_families;
+  // have to open default column familiy
+  column_families.push_back(ColumnFamilyDescriptor(
+      kDefaultColumnFamilyName, ColumnFamilyOptions()));
+  // open the new one, too
+  column_families.push_back(ColumnFamilyDescriptor(
+      "new_cf", ColumnFamilyOptions()));
+  std::vector<ColumnFamilyHandle*> handles;
+  s = DB::Open(DBOptions(), kDBPath, column_families, &handles, &db);
+  assert(s.ok());
+
+  // put and get from non-default column family
+  s = db->Put(WriteOptions(), handles[1], Slice("key"), Slice("value"));
+  assert(s.ok());
+  std::string value;
+  s = db->Get(ReadOptions(), handles[1], Slice("key"), &value);
+  assert(s.ok());
+
+  // atomic write
+  WriteBatch batch;
+  batch.Put(handles[0], Slice("key2"), Slice("value2"));
+  batch.Put(handles[1], Slice("key3"), Slice("value3"));
+  batch.Delete(handles[0], Slice("key"));
+  s = db->Write(WriteOptions(), &batch);
+  assert(s.ok());
+
+  // drop column family
+  s = db->DropColumnFamily(handles[1]);
+  assert(s.ok());
+
+  // close db
+  for (auto handle : handles) {
+    delete handle;
+  }
+  delete db;
+
+  return 0;
+}
@@ -0,0 +1,41 @@
+// Copyright (c) 2013, Facebook, Inc.  All rights reserved.
+// This source code is licensed under the BSD-style license found in the
+// LICENSE file in the root directory of this source tree. An additional grant
+// of patent rights can be found in the PATENTS file in the same directory.
+#include <cstdio>
+#include <string>
+
+#include "rocksdb/db.h"
+#include "rocksdb/slice.h"
+#include "rocksdb/options.h"
+
+using namespace rocksdb;
+
+std::string kDBPath = "/tmp/rocksdb_simple_example";
+
+int main() {
+  DB* db;
+  Options options;
+  // Optimize RocksDB. This is the easiest way to get RocksDB to perform well
+  options.IncreaseParallelism();
+  options.OptimizeLevelStyleCompaction();
+  // create the DB if it's not already present
+  options.create_if_missing = true;
+
+  // open DB
+  Status s = DB::Open(options, kDBPath, &db);
+  assert(s.ok());
+
+  // Put key-value
+  s = db->Put(WriteOptions(), "key", "value");
+  assert(s.ok());
+  std::string value;
+  // get value
+  s = db->Get(ReadOptions(), "key", &value);
+  assert(s.ok());
+  assert(value == "value");
+
+  delete db;
+
+  return 0;
+}
@@ -1,19 +1,16 @@
 This directory contains the hdfs extensions needed to make rocksdb store
 files in HDFS.

-The hdfs.h file is copied from the Apache Hadoop 1.0 source code. 
-It defines the libhdfs library
-(http://hadoop.apache.org/common/docs/r0.20.2/libhdfs.html) to access 
-data in HDFS.  The libhdfs.a is copied from the Apache Hadoop 1.0 build. 
-It implements the API defined in hdfs.h. If your hadoop cluster is running
-a different hadoop release, then install these two files manually from your
-hadoop distribution and then recompile rocksdb.
+It has been compiled and testing against CDH 4.4 (2.0.0+1475-1.cdh4.4.0.p0.23~precise-cdh4.4.0).
+
+The configuration assumes that packages libhdfs0, libhdfs0-dev are 
+installed which basically means that hdfs.h is in /usr/include and libhdfs in /usr/lib

 The env_hdfs.h file defines the rocksdb objects that are needed to talk to an
 underlying filesystem. 

 If you want to compile rocksdb with hdfs support, please set the following
-enviroment variables appropriately:
+enviroment variables appropriately (also defined in setup.sh for convenience)
   USE_HDFS=1
   JAVA_HOME=/usr/local/jdk-6u22-64
   LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/local/jdk-6u22-64/jre/lib/amd64/server:/usr/local/jdk-6u22-64/jre/lib/amd64/:./snappy/libs
@@ -14,13 +14,10 @@
 #include "rocksdb/status.h"

 #ifdef USE_HDFS
-#include "hdfs/hdfs.h"
+#include <hdfs.h>

 namespace rocksdb {

-static const std::string kProto = "hdfs://";
-static const std::string pathsep = "/";
-
 // Thrown during execution when there is an issue with the supplied
 // arguments.
 class HdfsUsageException : public std::exception { };
@@ -58,20 +55,23 @@ class HdfsEnv : public Env {
  }

  virtual Status NewSequentialFile(const std::string& fname,
-                                   SequentialFile** result);
+                                   std::unique_ptr<SequentialFile>* result,
+                                   const EnvOptions& options);

  virtual Status NewRandomAccessFile(const std::string& fname,
-                                     RandomAccessFile** result);
+                                     std::unique_ptr<RandomAccessFile>* result,
+                                     const EnvOptions& options);

  virtual Status NewWritableFile(const std::string& fname,
-                                 WritableFile** result);
+                                 std::unique_ptr<WritableFile>* result,
+                                 const EnvOptions& options);

  virtual Status NewRandomRWFile(const std::string& fname,
-                                 unique_ptr<RandomRWFile>* result,
+                                 std::unique_ptr<RandomRWFile>* result,
                                 const EnvOptions& options);

  virtual Status NewDirectory(const std::string& name,
-                              unique_ptr<Directory>* result);
+                              std::unique_ptr<Directory>* result);

  virtual bool FileExists(const std::string& fname);

@@ -97,7 +97,8 @@ class HdfsEnv : public Env {

  virtual Status UnlockFile(FileLock* lock);

-  virtual Status NewLogger(const std::string& fname, Logger** result);
+  virtual Status NewLogger(const std::string& fname,
+                           std::shared_ptr<Logger>* result);

  virtual void Schedule(void (*function)(void* arg), void* arg,
                        Priority pri = LOW) {
@@ -161,6 +162,9 @@ class HdfsEnv : public Env {
                        // object here so that we can use posix timers,
                        // posix threads, etc.

+  static const std::string kProto;
+  static const std::string pathsep;
+
  /**
   * If the URI is specified of the form hdfs://server:port/path,
   * then connect to the specified cluster
@@ -1,477 +0,0 @@
-//  Copyright (c) 2013, Facebook, Inc.  All rights reserved.
-//  This source code is licensed under the BSD-style license found in the
-//  LICENSE file in the root directory of this source tree. An additional grant
-//  of patent rights can be found in the PATENTS file in the same directory.
-//
-#ifndef LIBHDFS_HDFS_H
-#define LIBHDFS_HDFS_H
-
-#include <sys/types.h>
-#include <sys/stat.h>
-
-#include <fcntl.h>
-#include <stdio.h>
-#include <stdint.h>
-#include <string.h>
-#include <stdlib.h>
-#include <time.h>
-#include <errno.h>
-
-#include <jni.h>
-
-#ifndef O_RDONLY
-#define O_RDONLY 1
-#endif
-
-#ifndef O_WRONLY 
-#define O_WRONLY 2
-#endif
-
-#ifndef EINTERNAL
-#define EINTERNAL 255 
-#endif
-
-
-/** All APIs set errno to meaningful values */
-#ifdef __cplusplus
-extern  "C" {
-#endif
-
-    /**
-     * Some utility decls used in libhdfs.
-     */
-
-    typedef int32_t   tSize; /// size of data for read/write io ops 
-    typedef time_t    tTime; /// time type in seconds
-    typedef int64_t   tOffset;/// offset within the file
-    typedef uint16_t  tPort; /// port
-    typedef enum tObjectKind {
-        kObjectKindFile = 'F',
-        kObjectKindDirectory = 'D',
-    } tObjectKind;
-
-
-    /**
-     * The C reflection of org.apache.org.hadoop.FileSystem .
-     */
-    typedef void* hdfsFS;
-
-    
-    /**
-     * The C equivalent of org.apache.org.hadoop.FSData(Input|Output)Stream .
-     */
-    enum hdfsStreamType
-    {
-        UNINITIALIZED = 0,
-        INPUT = 1,
-        OUTPUT = 2,
-    };
-
-    
-    /**
-     * The 'file-handle' to a file in hdfs.
-     */
-    struct hdfsFile_internal {
-        void* file;
-        enum hdfsStreamType type;
-    };
-    typedef struct hdfsFile_internal* hdfsFile;
-      
-
-    /** 
-     * hdfsConnectAsUser - Connect to a hdfs file system as a specific user
-     * Connect to the hdfs.
-     * @param host A string containing either a host name, or an ip address
-     * of the namenode of a hdfs cluster. 'host' should be passed as NULL if
-     * you want to connect to local filesystem. 'host' should be passed as
-     * 'default' (and port as 0) to used the 'configured' filesystem
-     * (core-site/core-default.xml).
-     * @param port The port on which the server is listening.
-     * @param user the user name (this is hadoop domain user). Or NULL is equivelant to hhdfsConnect(host, port)
-     * @param groups the groups (these are hadoop domain groups)
-     * @return Returns a handle to the filesystem or NULL on error.
-     */
-     hdfsFS hdfsConnectAsUser(const char* host, tPort port, const char *user , const char *groups[], int groups_size );
-
-
-    /** 
-     * hdfsConnect - Connect to a hdfs file system.
-     * Connect to the hdfs.
-     * @param host A string containing either a host name, or an ip address
-     * of the namenode of a hdfs cluster. 'host' should be passed as NULL if
-     * you want to connect to local filesystem. 'host' should be passed as
-     * 'default' (and port as 0) to used the 'configured' filesystem
-     * (core-site/core-default.xml).
-     * @param port The port on which the server is listening.
-     * @return Returns a handle to the filesystem or NULL on error.
-     */
-     hdfsFS hdfsConnect(const char* host, tPort port);
-
-
-    /**
-     * This are the same as hdfsConnectAsUser except that every invocation returns a new FileSystem handle.
-     * Applications should call a hdfsDisconnect for every call to hdfsConnectAsUserNewInstance.
-     */
-     hdfsFS hdfsConnectAsUserNewInstance(const char* host, tPort port, const char *user , const char *groups[], int groups_size );
-     hdfsFS hdfsConnectNewInstance(const char* host, tPort port);
-     hdfsFS hdfsConnectPath(const char* uri);
-
-    /** 
-     * hdfsDisconnect - Disconnect from the hdfs file system.
-     * Disconnect from hdfs.
-     * @param fs The configured filesystem handle.
-     * @return Returns 0 on success, -1 on error.  
-     */
-    int hdfsDisconnect(hdfsFS fs);
-        
-
-    /** 
-     * hdfsOpenFile - Open a hdfs file in given mode.
-     * @param fs The configured filesystem handle.
-     * @param path The full path to the file.
-     * @param flags - an | of bits/fcntl.h file flags - supported flags are O_RDONLY, O_WRONLY (meaning create or overwrite i.e., implies O_TRUNCAT), 
-     * O_WRONLY|O_APPEND. Other flags are generally ignored other than (O_RDWR || (O_EXCL & O_CREAT)) which return NULL and set errno equal ENOTSUP.
-     * @param bufferSize Size of buffer for read/write - pass 0 if you want
-     * to use the default configured values.
-     * @param replication Block replication - pass 0 if you want to use
-     * the default configured values.
-     * @param blocksize Size of block - pass 0 if you want to use the
-     * default configured values.
-     * @return Returns the handle to the open file or NULL on error.
-     */
-    hdfsFile hdfsOpenFile(hdfsFS fs, const char* path, int flags,
-                          int bufferSize, short replication, tSize blocksize);
-
-
-    /** 
-     * hdfsCloseFile - Close an open file. 
-     * @param fs The configured filesystem handle.
-     * @param file The file handle.
-     * @return Returns 0 on success, -1 on error.  
-     */
-    int hdfsCloseFile(hdfsFS fs, hdfsFile file);
-
-
-    /** 
-     * hdfsExists - Checks if a given path exsits on the filesystem 
-     * @param fs The configured filesystem handle.
-     * @param path The path to look for
-     * @return Returns 0 on exists, 1 on non-exists, -1/-2 on error.  
-     */
-    int hdfsExists(hdfsFS fs, const char *path);
-
-
-    /** 
-     * hdfsSeek - Seek to given offset in file. 
-     * This works only for files opened in read-only mode. 
-     * @param fs The configured filesystem handle.
-     * @param file The file handle.
-     * @param desiredPos Offset into the file to seek into.
-     * @return Returns 0 on success, -1 on error.  
-     */
-    int hdfsSeek(hdfsFS fs, hdfsFile file, tOffset desiredPos); 
-
-
-    /** 
-     * hdfsTell - Get the current offset in the file, in bytes.
-     * @param fs The configured filesystem handle.
-     * @param file The file handle.
-     * @return Current offset, -1 on error.
-     */
-    tOffset hdfsTell(hdfsFS fs, hdfsFile file);
-
-
-    /** 
-     * hdfsRead - Read data from an open file.
-     * @param fs The configured filesystem handle.
-     * @param file The file handle.
-     * @param buffer The buffer to copy read bytes into.
-     * @param length The length of the buffer.
-     * @return Returns the number of bytes actually read, possibly less
-     * than than length;-1 on error.
-     */
-    tSize hdfsRead(hdfsFS fs, hdfsFile file, void* buffer, tSize length);
-
-
-    /** 
-     * hdfsPread - Positional read of data from an open file.
-     * @param fs The configured filesystem handle.
-     * @param file The file handle.
-     * @param position Position from which to read
-     * @param buffer The buffer to copy read bytes into.
-     * @param length The length of the buffer.
-     * @return Returns the number of bytes actually read, possibly less than
-     * than length;-1 on error.
-     */
-    tSize hdfsPread(hdfsFS fs, hdfsFile file, tOffset position,
-                    void* buffer, tSize length);
-
-
-    /** 
-     * hdfsWrite - Write data into an open file.
-     * @param fs The configured filesystem handle.
-     * @param file The file handle.
-     * @param buffer The data.
-     * @param length The no. of bytes to write. 
-     * @return Returns the number of bytes written, -1 on error.
-     */
-    tSize hdfsWrite(hdfsFS fs, hdfsFile file, const void* buffer,
-                    tSize length);
-
-
-    /** 
-     * hdfsWrite - Flush the data. 
-     * @param fs The configured filesystem handle.
-     * @param file The file handle.
-     * @return Returns 0 on success, -1 on error. 
-     */
-    int hdfsFlush(hdfsFS fs, hdfsFile file);
-
-    /**
-     * hdfsSync - Sync the data to persistent store.
-     * @param fs The configured filesystem handle.
-     * @param file The file handle.
-     * @return Returns 0 on success, -1 on error.
-     */
-    int hdfsSync(hdfsFS fs, hdfsFile file);
-
-    /**
-     * hdfsGetNumReplicasInPipeline - get number of remaining replicas in 
-     * pipeline
-     * @param fs The configured filesystem handle
-     * @param file the file handle
-     * @return returns the # of datanodes in the write pipeline; -1 on error
-     */
-   int hdfsGetNumCurrentReplicas(hdfsFS, hdfsFile file);
-
-    /**
-     * hdfsAvailable - Number of bytes that can be read from this
-     * input stream without blocking.
-     * @param fs The configured filesystem handle.
-     * @param file The file handle.
-     * @return Returns available bytes; -1 on error. 
-     */
-    int hdfsAvailable(hdfsFS fs, hdfsFile file);
-
-
-    /**
-     * hdfsCopy - Copy file from one filesystem to another.
-     * @param srcFS The handle to source filesystem.
-     * @param src The path of source file. 
-     * @param dstFS The handle to destination filesystem.
-     * @param dst The path of destination file. 
-     * @return Returns 0 on success, -1 on error. 
-     */
-    int hdfsCopy(hdfsFS srcFS, const char* src, hdfsFS dstFS, const char* dst);
-
-
-    /**
-     * hdfsMove - Move file from one filesystem to another.
-     * @param srcFS The handle to source filesystem.
-     * @param src The path of source file. 
-     * @param dstFS The handle to destination filesystem.
-     * @param dst The path of destination file. 
-     * @return Returns 0 on success, -1 on error. 
-     */
-    int hdfsMove(hdfsFS srcFS, const char* src, hdfsFS dstFS, const char* dst);
-
-
-    /**
-     * hdfsDelete - Delete file. 
-     * @param fs The configured filesystem handle.
-     * @param path The path of the file. 
-     * @return Returns 0 on success, -1 on error. 
-     */
-    int hdfsDelete(hdfsFS fs, const char* path);
-
-
-    /**
-     * hdfsRename - Rename file. 
-     * @param fs The configured filesystem handle.
-     * @param oldPath The path of the source file. 
-     * @param newPath The path of the destination file. 
-     * @return Returns 0 on success, -1 on error. 
-     */
-    int hdfsRename(hdfsFS fs, const char* oldPath, const char* newPath);
-
-
-    /** 
-     * hdfsGetWorkingDirectory - Get the current working directory for
-     * the given filesystem.
-     * @param fs The configured filesystem handle.
-     * @param buffer The user-buffer to copy path of cwd into. 
-     * @param bufferSize The length of user-buffer.
-     * @return Returns buffer, NULL on error.
-     */
-    char* hdfsGetWorkingDirectory(hdfsFS fs, char *buffer, size_t bufferSize);
-
-
-    /** 
-     * hdfsSetWorkingDirectory - Set the working directory. All relative
-     * paths will be resolved relative to it.
-     * @param fs The configured filesystem handle.
-     * @param path The path of the new 'cwd'. 
-     * @return Returns 0 on success, -1 on error. 
-     */
-    int hdfsSetWorkingDirectory(hdfsFS fs, const char* path);
-
-
-    /** 
-     * hdfsCreateDirectory - Make the given file and all non-existent
-     * parents into directories.
-     * @param fs The configured filesystem handle.
-     * @param path The path of the directory. 
-     * @return Returns 0 on success, -1 on error. 
-     */
-    int hdfsCreateDirectory(hdfsFS fs, const char* path);
-
-
-    /** 
-     * hdfsSetReplication - Set the replication of the specified
-     * file to the supplied value
-     * @param fs The configured filesystem handle.
-     * @param path The path of the file. 
-     * @return Returns 0 on success, -1 on error. 
-     */
-    int hdfsSetReplication(hdfsFS fs, const char* path, int16_t replication);
-
-
-    /** 
-     * hdfsFileInfo - Information about a file/directory.
-     */
-    typedef struct  {
-        tObjectKind mKind;   /* file or directory */
-        char *mName;         /* the name of the file */
-        tTime mLastMod;      /* the last modification time for the file in seconds */
-        tOffset mSize;       /* the size of the file in bytes */
-        short mReplication;    /* the count of replicas */
-        tOffset mBlockSize;  /* the block size for the file */
-        char *mOwner;        /* the owner of the file */
-        char *mGroup;        /* the group associated with the file */
-        short mPermissions;  /* the permissions associated with the file */
-        tTime mLastAccess;    /* the last access time for the file in seconds */
-    } hdfsFileInfo;
-
-
-    /** 
-     * hdfsListDirectory - Get list of files/directories for a given
-     * directory-path. hdfsFreeFileInfo should be called to deallocate memory if
-     * the function returns non-NULL value.
-     * @param fs The configured filesystem handle.
-     * @param path The path of the directory. 
-     * @param numEntries Set to the number of files/directories in path.
-     * @return Returns a dynamically-allocated array of hdfsFileInfo
-     * objects; NULL if empty or on error.
-     * on error, numEntries will be -1.
-     */
-    hdfsFileInfo *hdfsListDirectory(hdfsFS fs, const char* path,
-                                    int *numEntries);
-
-
-    /** 
-     * hdfsGetPathInfo - Get information about a path as a (dynamically
-     * allocated) single hdfsFileInfo struct. hdfsFreeFileInfo should be
-     * called when the pointer is no longer needed.
-     * @param fs The configured filesystem handle.
-     * @param path The path of the file. 
-     * @return Returns a dynamically-allocated hdfsFileInfo object;
-     * NULL on error.
-     */
-    hdfsFileInfo *hdfsGetPathInfo(hdfsFS fs, const char* path);
-
-
-    /** 
-     * hdfsFreeFileInfo - Free up the hdfsFileInfo array (including fields) 
-     * @param hdfsFileInfo The array of dynamically-allocated hdfsFileInfo
-     * objects.
-     * @param numEntries The size of the array.
-     */
-    void hdfsFreeFileInfo(hdfsFileInfo *hdfsFileInfo, int numEntries);
-
-
-    /** 
-     * hdfsGetHosts - Get hostnames where a particular block (determined by
-     * pos & blocksize) of a file is stored. The last element in the array
-     * is NULL. Due to replication, a single block could be present on
-     * multiple hosts.
-     * @param fs The configured filesystem handle.
-     * @param path The path of the file. 
-     * @param start The start of the block.
-     * @param length The length of the block.
-     * @return Returns a dynamically-allocated 2-d array of blocks-hosts;
-     * NULL on error.
-     */
-    char*** hdfsGetHosts(hdfsFS fs, const char* path, 
-            tOffset start, tOffset length);
-
-
-    /** 
-     * hdfsFreeHosts - Free up the structure returned by hdfsGetHosts
-     * @param hdfsFileInfo The array of dynamically-allocated hdfsFileInfo
-     * objects.
-     * @param numEntries The size of the array.
-     */
-    void hdfsFreeHosts(char ***blockHosts);
-
-
-    /** 
-     * hdfsGetDefaultBlockSize - Get the optimum blocksize.
-     * @param fs The configured filesystem handle.
-     * @return Returns the blocksize; -1 on error. 
-     */
-    tOffset hdfsGetDefaultBlockSize(hdfsFS fs);
-
-
-    /** 
-     * hdfsGetCapacity - Return the raw capacity of the filesystem.  
-     * @param fs The configured filesystem handle.
-     * @return Returns the raw-capacity; -1 on error. 
-     */
-    tOffset hdfsGetCapacity(hdfsFS fs);
-
-
-    /** 
-     * hdfsGetUsed - Return the total raw size of all files in the filesystem.
-     * @param fs The configured filesystem handle.
-     * @return Returns the total-size; -1 on error. 
-     */
-    tOffset hdfsGetUsed(hdfsFS fs);
-
-    /** 
-     * hdfsChown 
-     * @param fs The configured filesystem handle.
-     * @param path the path to the file or directory
-     * @param owner this is a string in Hadoop land. Set to null or "" if only setting group
-     * @param group  this is a string in Hadoop land. Set to null or "" if only setting user
-     * @return 0 on success else -1
-     */
-    int hdfsChown(hdfsFS fs, const char* path, const char *owner, const char *group);
-
-    /** 
-     * hdfsChmod
-     * @param fs The configured filesystem handle.
-     * @param path the path to the file or directory
-     * @param mode the bitmask to set it to
-     * @return 0 on success else -1
-     */
-      int hdfsChmod(hdfsFS fs, const char* path, short mode);
-
-    /** 
-     * hdfsUtime
-     * @param fs The configured filesystem handle.
-     * @param path the path to the file or directory
-     * @param mtime new modification time or 0 for only set access time in seconds
-     * @param atime new access time or 0 for only set modification time in seconds
-     * @return 0 on success else -1
-     */
-    int hdfsUtime(hdfsFS fs, const char* path, tTime mtime, tTime atime);
-    
-#ifdef __cplusplus
-}
-#endif
-
-#endif /*LIBHDFS_HDFS_H*/
-
-/**
- * vim: ts=4: sw=4: et
- */
@@ -0,0 +1,7 @@
+export USE_HDFS=1
+export LD_LIBRARY_PATH=$JAVA_HOME/jre/lib/amd64/server:$JAVA_HOME/jre/lib/amd64:/usr/lib/hadoop/lib/native
+
+export CLASSPATH=
+for f in `find /usr/lib/hadoop-hdfs | grep jar`; do export CLASSPATH=$CLASSPATH:$f; done
+for f in `find /usr/lib/hadoop | grep jar`; do export CLASSPATH=$CLASSPATH:$f; done
+for f in `find /usr/lib/hadoop/client | grep jar`; do export CLASSPATH=$CLASSPATH:$f; done
@@ -6,8 +6,8 @@
  Use of this source code is governed by a BSD-style license that can be
  found in the LICENSE file. See the AUTHORS file for names of contributors.

-  C bindings for leveldb.  May be useful as a stable ABI that can be
-  used by programs that keep leveldb in a shared library, or for
+  C bindings for rocksdb.  May be useful as a stable ABI that can be
+  used by programs that keep rocksdb in a shared library, or for
  a JNI api.

  Does not support:
@@ -56,8 +56,18 @@ extern "C" {

 typedef struct rocksdb_t                 rocksdb_t;
 typedef struct rocksdb_cache_t           rocksdb_cache_t;
+typedef struct rocksdb_compactionfilter_t rocksdb_compactionfilter_t;
+typedef struct rocksdb_compactionfiltercontext_t
+    rocksdb_compactionfiltercontext_t;
+typedef struct rocksdb_compactionfilterfactory_t
+    rocksdb_compactionfilterfactory_t;
+typedef struct rocksdb_compactionfilterv2_t
+    rocksdb_compactionfilterv2_t;
+typedef struct rocksdb_compactionfilterfactoryv2_t
+    rocksdb_compactionfilterfactoryv2_t;
 typedef struct rocksdb_comparator_t      rocksdb_comparator_t;
 typedef struct rocksdb_env_t             rocksdb_env_t;
+typedef struct rocksdb_fifo_compaction_options_t rocksdb_fifo_compaction_options_t;
 typedef struct rocksdb_filelock_t        rocksdb_filelock_t;
 typedef struct rocksdb_filterpolicy_t    rocksdb_filterpolicy_t;
 typedef struct rocksdb_flushoptions_t    rocksdb_flushoptions_t;
@@ -75,6 +85,7 @@ typedef struct rocksdb_writebatch_t      rocksdb_writebatch_t;
 typedef struct rocksdb_writeoptions_t    rocksdb_writeoptions_t;
 typedef struct rocksdb_universal_compaction_options_t rocksdb_universal_compaction_options_t;
 typedef struct rocksdb_livefiles_t     rocksdb_livefiles_t;
+typedef struct rocksdb_column_family_handle_t rocksdb_column_family_handle_t;

 /* DB operations */

@@ -89,6 +100,45 @@ extern rocksdb_t* rocksdb_open_for_read_only(
    unsigned char error_if_log_file_exist,
    char** errptr);

+extern rocksdb_t* rocksdb_open_column_families(
+    const rocksdb_options_t* options,
+    const char* name,
+    int num_column_families,
+    const char** column_family_names,
+    const rocksdb_options_t** column_family_options,
+    rocksdb_column_family_handle_t** column_family_handles,
+    char** errptr);
+
+extern rocksdb_t* rocksdb_open_for_read_only_column_families(
+    const rocksdb_options_t* options,
+    const char* name,
+    int num_column_families,
+    const char** column_family_names,
+    const rocksdb_options_t** column_family_options,
+    rocksdb_column_family_handle_t** column_family_handles,
+    unsigned char error_if_log_file_exist,
+    char** errptr);
+
+char** rocksdb_list_column_families(
+    const rocksdb_options_t* options,
+    const char* name,
+    size_t* lencf,
+    char** errptr);
+void rocksdb_list_column_families_destroy(char** list, size_t len);
+
+extern rocksdb_column_family_handle_t* rocksdb_create_column_family(
+    rocksdb_t* db,
+    const rocksdb_options_t* column_family_options,
+    const char* column_family_name,
+    char** errptr);
+
+extern void rocksdb_drop_column_family(
+    rocksdb_t* db,
+    rocksdb_column_family_handle_t* handle,
+    char** errptr);
+
+extern void rocksdb_column_family_handle_destroy(rocksdb_column_family_handle_t*);
+
 extern void rocksdb_close(rocksdb_t* db);

 extern void rocksdb_put(
@@ -98,12 +148,27 @@ extern void rocksdb_put(
    const char* val, size_t vallen,
    char** errptr);

+extern void rocksdb_put_cf(
+    rocksdb_t* db,
+    const rocksdb_writeoptions_t* options,
+    rocksdb_column_family_handle_t* column_family,
+    const char* key, size_t keylen,
+    const char* val, size_t vallen,
+    char** errptr);
+
 extern void rocksdb_delete(
    rocksdb_t* db,
    const rocksdb_writeoptions_t* options,
    const char* key, size_t keylen,
    char** errptr);

+void rocksdb_delete_cf(
+    rocksdb_t* db,
+    const rocksdb_writeoptions_t* options,
+    rocksdb_column_family_handle_t* column_family,
+    const char* key, size_t keylen,
+    char** errptr);
+
 extern void rocksdb_merge(
    rocksdb_t* db,
    const rocksdb_writeoptions_t* options,
@@ -111,6 +176,14 @@ extern void rocksdb_merge(
    const char* val, size_t vallen,
    char** errptr);

+extern void rocksdb_merge_cf(
+    rocksdb_t* db,
+    const rocksdb_writeoptions_t* options,
+    rocksdb_column_family_handle_t* column_family,
+    const char* key, size_t keylen,
+    const char* val, size_t vallen,
+    char** errptr);
+
 extern void rocksdb_write(
    rocksdb_t* db,
    const rocksdb_writeoptions_t* options,
@@ -126,10 +199,23 @@ extern char* rocksdb_get(
    size_t* vallen,
    char** errptr);

+extern char* rocksdb_get_cf(
+    rocksdb_t* db,
+    const rocksdb_readoptions_t* options,
+    rocksdb_column_family_handle_t* column_family,
+    const char* key, size_t keylen,
+    size_t* vallen,
+    char** errptr);
+
 extern rocksdb_iterator_t* rocksdb_create_iterator(
    rocksdb_t* db,
    const rocksdb_readoptions_t* options);

+extern rocksdb_iterator_t* rocksdb_create_iterator_cf(
+    rocksdb_t* db,
+    const rocksdb_readoptions_t* options,
+    rocksdb_column_family_handle_t* column_family);
+
 extern const rocksdb_snapshot_t* rocksdb_create_snapshot(
    rocksdb_t* db);

@@ -143,6 +229,11 @@ extern char* rocksdb_property_value(
    rocksdb_t* db,
    const char* propname);

+extern char* rocksdb_property_value_cf(
+    rocksdb_t* db,
+    rocksdb_column_family_handle_t* column_family,
+    const char* propname);
+
 extern void rocksdb_approximate_sizes(
    rocksdb_t* db,
    int num_ranges,
@@ -150,11 +241,25 @@ extern void rocksdb_approximate_sizes(
    const char* const* range_limit_key, const size_t* range_limit_key_len,
    uint64_t* sizes);

+extern void rocksdb_approximate_sizes_cf(
+    rocksdb_t* db,
+    rocksdb_column_family_handle_t* column_family,
+    int num_ranges,
+    const char* const* range_start_key, const size_t* range_start_key_len,
+    const char* const* range_limit_key, const size_t* range_limit_key_len,
+    uint64_t* sizes);
+
 extern void rocksdb_compact_range(
    rocksdb_t* db,
    const char* start_key, size_t start_key_len,
    const char* limit_key, size_t limit_key_len);

+extern void rocksdb_compact_range_cf(
+    rocksdb_t* db,
+    rocksdb_column_family_handle_t* column_family,
+    const char* start_key, size_t start_key_len,
+    const char* limit_key, size_t limit_key_len);
+
 extern void rocksdb_delete_file(
    rocksdb_t* db,
    const char* name);
@@ -204,6 +309,8 @@ extern void rocksdb_iter_get_error(const rocksdb_iterator_t*, char** errptr);
 /* Write batch */

 extern rocksdb_writebatch_t* rocksdb_writebatch_create();
+extern rocksdb_writebatch_t* rocksdb_writebatch_create_from(const char* rep,
+                                                            size_t size);
 extern void rocksdb_writebatch_destroy(rocksdb_writebatch_t*);
 extern void rocksdb_writebatch_clear(rocksdb_writebatch_t*);
 extern int rocksdb_writebatch_count(rocksdb_writebatch_t*);
@@ -211,13 +318,27 @@ extern void rocksdb_writebatch_put(
    rocksdb_writebatch_t*,
    const char* key, size_t klen,
    const char* val, size_t vlen);
+extern void rocksdb_writebatch_put_cf(
+    rocksdb_writebatch_t*,
+    rocksdb_column_family_handle_t* column_family,
+    const char* key, size_t klen,
+    const char* val, size_t vlen);
 extern void rocksdb_writebatch_merge(
    rocksdb_writebatch_t*,
    const char* key, size_t klen,
    const char* val, size_t vlen);
+extern void rocksdb_writebatch_merge_cf(
+    rocksdb_writebatch_t*,
+    rocksdb_column_family_handle_t* column_family,
+    const char* key, size_t klen,
+    const char* val, size_t vlen);
 extern void rocksdb_writebatch_delete(
    rocksdb_writebatch_t*,
    const char* key, size_t klen);
+extern void rocksdb_writebatch_delete_cf(
+    rocksdb_writebatch_t*,
+    rocksdb_column_family_handle_t* column_family,
+    const char* key, size_t klen);
 extern void rocksdb_writebatch_iterate(
    rocksdb_writebatch_t*,
    void* state,
@@ -229,11 +350,28 @@ extern const char* rocksdb_writebatch_data(rocksdb_writebatch_t*, size_t *size);

 extern rocksdb_options_t* rocksdb_options_create();
 extern void rocksdb_options_destroy(rocksdb_options_t*);
+extern void rocksdb_options_increase_parallelism(
+    rocksdb_options_t* opt, int total_threads);
+extern void rocksdb_options_optimize_for_point_lookup(
+    rocksdb_options_t* opt);
+extern void rocksdb_options_optimize_level_style_compaction(
+    rocksdb_options_t* opt, uint64_t memtable_memory_budget);
+extern void rocksdb_options_optimize_universal_style_compaction(
+    rocksdb_options_t* opt, uint64_t memtable_memory_budget);
+extern void rocksdb_options_set_compaction_filter(
+    rocksdb_options_t*,
+    rocksdb_compactionfilter_t*);
+extern void rocksdb_options_set_compaction_filter_factory(
+    rocksdb_options_t*, rocksdb_compactionfilterfactory_t*);
+extern void rocksdb_options_set_compaction_filter_factory_v2(
+    rocksdb_options_t*,
+    rocksdb_compactionfilterfactoryv2_t*);
 extern void rocksdb_options_set_comparator(
    rocksdb_options_t*,
    rocksdb_comparator_t*);
-extern void rocksdb_options_set_merge_operator(rocksdb_options_t*,
-                                               rocksdb_mergeoperator_t*);
+extern void rocksdb_options_set_merge_operator(
+    rocksdb_options_t*,
+    rocksdb_mergeoperator_t*);
 extern void rocksdb_options_set_compression_per_level(
  rocksdb_options_t* opt,
  int* level_values,
@@ -243,6 +381,8 @@ extern void rocksdb_options_set_filter_policy(
    rocksdb_filterpolicy_t*);
 extern void rocksdb_options_set_create_if_missing(
    rocksdb_options_t*, unsigned char);
+extern void rocksdb_options_set_create_missing_column_families(
+    rocksdb_options_t*, unsigned char);
 extern void rocksdb_options_set_error_if_exists(
    rocksdb_options_t*, unsigned char);
 extern void rocksdb_options_set_paranoid_checks(
@@ -397,10 +537,77 @@ extern void rocksdb_options_set_compression(rocksdb_options_t*, int);

 enum {
  rocksdb_level_compaction = 0,
-  rocksdb_universal_compaction = 1
+  rocksdb_universal_compaction = 1,
+  rocksdb_fifo_compaction = 2
 };
 extern void rocksdb_options_set_compaction_style(rocksdb_options_t*, int);
 extern void rocksdb_options_set_universal_compaction_options(rocksdb_options_t*, rocksdb_universal_compaction_options_t*);
+extern void rocksdb_options_set_fifo_compaction_options(rocksdb_options_t* opt,
+    rocksdb_fifo_compaction_options_t* fifo);
+
+/* Compaction Filter */
+
+extern rocksdb_compactionfilter_t* rocksdb_compactionfilter_create(
+    void* state,
+    void (*destructor)(void*),
+    unsigned char (*filter)(
+        void*,
+        int level,
+        const char* key, size_t key_length,
+        const char* existing_value, size_t value_length,
+        char** new_value, size_t *new_value_length,
+        unsigned char* value_changed),
+    const char* (*name)(void*));
+extern void rocksdb_compactionfilter_destroy(rocksdb_compactionfilter_t*);
+
+/* Compaction Filter Context */
+
+extern unsigned char rocksdb_compactionfiltercontext_is_full_compaction(
+    rocksdb_compactionfiltercontext_t* context);
+
+extern unsigned char rocksdb_compactionfiltercontext_is_manual_compaction(
+    rocksdb_compactionfiltercontext_t* context);
+
+/* Compaction Filter Factory */
+
+extern rocksdb_compactionfilterfactory_t*
+    rocksdb_compactionfilterfactory_create(
+        void* state, void (*destructor)(void*),
+        rocksdb_compactionfilter_t* (*create_compaction_filter)(
+            void*, rocksdb_compactionfiltercontext_t* context),
+        const char* (*name)(void*));
+extern void rocksdb_compactionfilterfactory_destroy(
+    rocksdb_compactionfilterfactory_t*);
+
+/* Compaction Filter V2 */
+
+extern rocksdb_compactionfilterv2_t* rocksdb_compactionfilterv2_create(
+    void* state,
+    void (*destructor)(void*),
+    // num_keys specifies the number of array entries in every *list parameter.
+    // New values added to the new_values_list should be malloc'd and will be
+    // freed by the caller. Specify true in the to_delete_list to remove an
+    // entry during compaction; false to keep it.
+    void (*filter)(
+        void*, int level, size_t num_keys,
+        const char* const* keys_list, const size_t* keys_list_sizes,
+        const char* const* existing_values_list, const size_t* existing_values_list_sizes,
+        char** new_values_list, size_t* new_values_list_sizes,
+        unsigned char* to_delete_list),
+    const char* (*name)(void*));
+extern void rocksdb_compactionfilterv2_destroy(rocksdb_compactionfilterv2_t*);
+
+/* Compaction Filter Factory V2 */
+
+extern rocksdb_compactionfilterfactoryv2_t* rocksdb_compactionfilterfactoryv2_create(
+    void* state,
+    rocksdb_slicetransform_t* prefix_extractor,
+    void (*destructor)(void*),
+    rocksdb_compactionfilterv2_t* (*create_compaction_filter_v2)(
+        void*, const rocksdb_compactionfiltercontext_t* context),
+    const char* (*name)(void*));
+extern void rocksdb_compactionfilterfactoryv2_destroy(rocksdb_compactionfilterfactoryv2_t*);
+
 /* Comparator */

 extern rocksdb_comparator_t* rocksdb_comparator_create(
@@ -546,6 +753,12 @@ extern void rocksdb_universal_compaction_options_set_stop_style(
 extern void rocksdb_universal_compaction_options_destroy(
  rocksdb_universal_compaction_options_t*);

+extern rocksdb_fifo_compaction_options_t* rocksdb_fifo_compaction_options_create();
+extern void rocksdb_fifo_compaction_options_set_max_table_files_size(
+    rocksdb_fifo_compaction_options_t* fifo_opts, uint64_t size);
+extern void rocksdb_fifo_compaction_options_destroy(
+    rocksdb_fifo_compaction_options_t* fifo_opts);
+
 extern int rocksdb_livefiles_count(
  const rocksdb_livefiles_t*);
 extern const char* rocksdb_livefiles_name(
@@ -86,7 +86,7 @@ class CompactionFilterV2 {
  //
  // Each entry in the return vector indicates if the corresponding kv should
  // be preserved in the output of this compaction run. The application can
-  // inspect the exisitng values of the keys and make decision based on it.
+  // inspect the existing values of the keys and make decision based on it.
  //
  // When a value is to be preserved, the application has the option
  // to modify the entry in existing_values and pass it back through an entry
@@ -108,7 +108,7 @@ class CompactionFilterV2 {
 };

 // Each compaction will create a new CompactionFilter allowing the
-// application to know about different campactions
+// application to know about different compactions
 class CompactionFilterFactory {
 public:
  virtual ~CompactionFilterFactory() { }
@@ -120,7 +120,7 @@ class CompactionFilterFactory {
  virtual const char* Name() const = 0;
 };

-// Default implementaion of CompactionFilterFactory which does not
+// Default implementation of CompactionFilterFactory which does not
 // return any filter
 class DefaultCompactionFilterFactory : public CompactionFilterFactory {
 public:
@@ -175,7 +175,7 @@ class CompactionFilterFactoryV2 {
  const SliceTransform* prefix_extractor_;
 };

-// Default implementaion of CompactionFilterFactoryV2 which does not
+// Default implementation of CompactionFilterFactoryV2 which does not
 // return any filter
 class DefaultCompactionFilterFactoryV2 : public CompactionFilterFactoryV2 {
 public:
@@ -55,6 +55,7 @@ class Env;
 // Metadata associated with each SST file.
 struct LiveFileMetaData {
  std::string column_family_name;  // Name of the column family
+  std::string db_path;
  std::string name;                // Name of the file
  int level;               // Level at which this file resides.
  size_t size;             // File size in bytes.
@@ -159,6 +160,7 @@ class DB {
  virtual Status DropColumnFamily(ColumnFamilyHandle* column_family);

  // Set the database entry for "key" to "value".
+  // If "key" already exists, it will be overwritten.
  // Returns OK on success, and a non-OK status on error.
  // Note: consider setting options.sync = true.
  virtual Status Put(const WriteOptions& options,
@@ -305,6 +307,14 @@ class DB {
    return GetProperty(DefaultColumnFamily(), property, value);
  }

+  // Similar to GetProperty(), but only works for a subset of properties whose
+  // return value is an integer. Return the value by integer.
+  virtual bool GetIntProperty(ColumnFamilyHandle* column_family,
+                              const Slice& property, uint64_t* value) = 0;
+  virtual bool GetIntProperty(const Slice& property, uint64_t* value) {
+    return GetIntProperty(DefaultColumnFamily(), property, value);
+  }
+
  // For each i in [0,n-1], store in "sizes[i]", the approximate
  // file system space used by keys in "[range[i].start .. range[i].limit)".
  //
@@ -337,15 +347,17 @@ class DB {
  // hosting all the files. In this case, client could set reduce_level
  // to true, to move the files back to the minimum level capable of holding
  // the data set or a given level (specified by non-negative target_level).
+  // Compaction outputs should be placed in options.db_paths[target_path_id].
+  // Behavior is undefined if target_path_id is out of range.
  virtual Status CompactRange(ColumnFamilyHandle* column_family,
                              const Slice* begin, const Slice* end,
-                              bool reduce_level = false,
-                              int target_level = -1) = 0;
+                              bool reduce_level = false, int target_level = -1,
+                              uint32_t target_path_id = 0) = 0;
  virtual Status CompactRange(const Slice* begin, const Slice* end,
-                              bool reduce_level = false,
-                              int target_level = -1) {
+                              bool reduce_level = false, int target_level = -1,
+                              uint32_t target_path_id = 0) {
    return CompactRange(DefaultColumnFamily(), begin, end, reduce_level,
-                        target_level);
+                        target_level, target_path_id);
  }

  // Number of levels used for this DB.
@@ -396,7 +408,7 @@ class DB {
  // times have the same effect as calling it once.
  virtual Status DisableFileDeletions() = 0;

-  // Allow compactions to delete obselete files.
+  // Allow compactions to delete obsolete files.
  // If force == true, the call to EnableFileDeletions() will guarantee that
  // file deletions are enabled after the call, even if DisableFileDeletions()
  // was called multiple times before.
@@ -35,6 +35,7 @@ class WritableFile;
 class RandomRWFile;
 class Directory;
 struct DBOptions;
+class RateLimiter;

 using std::unique_ptr;
 using std::shared_ptr;
@@ -74,6 +75,9 @@ struct EnvOptions {
  // write. By default, we set it to true for MANIFEST writes and false for
  // WAL writes
  bool fallocate_with_keep_size = true;
+
+  // If not nullptr, write rate limiting is enabled for flush and compaction
+  RateLimiter* rate_limiter = nullptr;
 };

 class Env {
@@ -194,8 +198,16 @@ class Env {
  // REQUIRES: lock has not already been unlocked.
  virtual Status UnlockFile(FileLock* lock) = 0;

+  // Priority for scheduling job in thread pool
  enum Priority { LOW, HIGH, TOTAL };

+  // Priority for scheduling job in thread pool
+  enum IOPriority {
+    IO_LOW = 0,
+    IO_HIGH = 1,
+    IO_TOTAL = 2
+  };
+
  // Arrange to run "(*function)(arg)" once in a background thread, in
  // the thread pool specified by pri. By default, jobs go to the 'LOW'
  // priority thread pool.
@@ -371,7 +383,10 @@ class RandomAccessFile {
 // at a time to the file.
 class WritableFile {
 public:
-  WritableFile() : last_preallocated_block_(0), preallocation_block_size_ (0) {
+  WritableFile()
+    : last_preallocated_block_(0),
+      preallocation_block_size_(0),
+      io_priority_(Env::IO_TOTAL) {
  }
  virtual ~WritableFile();

@@ -390,6 +405,14 @@ class WritableFile {
    return Sync();
  }

+  /*
+   * Change the priority in rate limiter if rate limiting is enabled.
+   * If rate limiting is not enabled, this call has no effect.
+   */
+  virtual void SetIOPriority(Env::IOPriority pri) {
+    io_priority_ = pri;
+  }
+
  /*
   * Get the size of valid data in the file.
   */
@@ -474,6 +497,9 @@ class WritableFile {
  // No copying allowed
  WritableFile(const WritableFile&);
  void operator=(const WritableFile&);
+
+ protected:
+  Env::IOPriority io_priority_;
 };

 // A file abstraction for random reading and writing.
@@ -0,0 +1,34 @@
+// Copyright (c) 2014, Facebook, Inc.  All rights reserved.
+// This source code is licensed under the BSD-style license found in the
+// LICENSE file in the root directory of this source tree. An additional grant
+// of patent rights can be found in the PATENTS file in the same directory.
+
+#ifndef INCLUDE_ROCKSDB_IOSTATS_CONTEXT_H_
+#define INCLUDE_ROCKSDB_IOSTATS_CONTEXT_H_
+
+#include <stdint.h>
+#include <string>
+
+// A thread local context for gathering io-stats efficiently and transparently.
+namespace rocksdb {
+
+struct IOStatsContext {
+  // reset all io-stats counter to zero
+  void Reset();
+
+  std::string ToString() const;
+
+  // the thread pool id
+  uint64_t thread_pool_id;
+
+  // number of bytes that has been written.
+  uint64_t bytes_written;
+  // number of bytes that has been read.
+  uint64_t bytes_read;
+};
+
+extern __thread IOStatsContext iostats_context;
+
+}  // namespace rocksdb
+
+#endif  // INCLUDE_ROCKSDB_IOSTATS_CONTEXT_H_
@@ -4,13 +4,32 @@
 // of patent rights can be found in the PATENTS file in the same directory.
 #ifndef ROCKSDB_LITE
 #pragma once
+#include <string>
 #include "rocksdb/options.h"

 namespace rocksdb {

+// An interface for converting a slice to a readable string
+class SliceFormatter {
+ public:
+  virtual ~SliceFormatter() {}
+  virtual std::string Format(const Slice& s) const = 0;
+};
+
+// Options for customizing ldb tool (beyond the DB Options)
+struct LDBOptions {
+  // Create LDBOptions with default values for all fields
+  LDBOptions();
+
+  // Key formatter that converts a slice to a readable string.
+  // Default: Slice::ToString()
+  std::shared_ptr<SliceFormatter> key_formatter;
+};
+
 class LDBTool {
 public:
-  void Run(int argc, char** argv, Options = Options());
+  void Run(int argc, char** argv, Options db_options= Options(),
+           const LDBOptions& ldb_options = LDBOptions());
 };

 } // namespace rocksdb
@@ -44,6 +44,7 @@ class Arena;
 class LookupKey;
 class Slice;
 class SliceTransform;
+class Logger;

 typedef void* KeyHandle;

@@ -141,16 +142,21 @@ class MemTableRep {
  };

  // Return an iterator over the keys in this representation.
-  virtual Iterator* GetIterator() = 0;
-
-  // Return an iterator over at least the keys with the specified user key. The
-  // iterator may also allow access to other keys, but doesn't have to. Default:
-  // GetIterator().
-  virtual Iterator* GetIterator(const Slice& user_key) { return GetIterator(); }
+  // arena: If not null, the arena needs to be used to allocate the Iterator.
+  //        When destroying the iterator, the caller will not call "delete"
+  //        but Iterator::~Iterator() directly. The destructor needs to destroy
+  //        all the states but those allocated in arena.
+  virtual Iterator* GetIterator(Arena* arena = nullptr) = 0;

  // Return an iterator that has a special Seek semantics. The result of
  // a Seek might only include keys with the same prefix as the target key.
-  virtual Iterator* GetDynamicPrefixIterator() { return GetIterator(); }
+  // arena: If not null, the arena needs to be used to allocate the Iterator.
+  //        When destroying the iterator, the caller will not call "delete"
+  //        but Iterator::~Iterator() directly. The destructor needs to destroy
+  //        all the states but those allocated in arena.
+  virtual Iterator* GetDynamicPrefixIterator(Arena* arena = nullptr) {
+    return GetIterator(arena);
+  }

  // Return true if the current MemTableRep supports merge operator.
  // Default: true
@@ -174,7 +180,8 @@ class MemTableRepFactory {
 public:
  virtual ~MemTableRepFactory() {}
  virtual MemTableRep* CreateMemTableRep(const MemTableRep::KeyComparator&,
-      Arena*, const SliceTransform*) = 0;
+                                         Arena*, const SliceTransform*,
+                                         Logger* logger) = 0;
  virtual const char* Name() const = 0;
 };

@@ -182,8 +189,8 @@ class MemTableRepFactory {
 class SkipListFactory : public MemTableRepFactory {
 public:
  virtual MemTableRep* CreateMemTableRep(const MemTableRep::KeyComparator&,
-                                         Arena*,
-                                         const SliceTransform*) override;
+                                         Arena*, const SliceTransform*,
+                                         Logger* logger) override;
  virtual const char* Name() const override { return "SkipListFactory"; }
 };

@@ -201,9 +208,9 @@ class VectorRepFactory : public MemTableRepFactory {

 public:
  explicit VectorRepFactory(size_t count = 0) : count_(count) { }
-  virtual MemTableRep* CreateMemTableRep(
-      const MemTableRep::KeyComparator&, Arena*,
-      const SliceTransform*) override;
+  virtual MemTableRep* CreateMemTableRep(const MemTableRep::KeyComparator&,
+                                         Arena*, const SliceTransform*,
+                                         Logger* logger) override;
  virtual const char* Name() const override {
    return "VectorRepFactory";
  }
@@ -220,17 +227,27 @@ extern MemTableRepFactory* NewHashSkipListRepFactory(
    int32_t skiplist_branching_factor = 4
 );

-// The factory is to create memtables with a hashed linked list:
-// it contains a fixed array of buckets, each pointing to a sorted single
-// linked list (null if the bucket is empty).
+// The factory is to create memtables based on a hash table:
+// it contains a fixed array of buckets, each pointing to either a linked list
+// or a skip list if number of entries inside the bucket exceeds
+// threshold_use_skiplist.
 // @bucket_count: number of fixed array buckets
 // @huge_page_tlb_size: if <=0, allocate the hash table bytes from malloc.
 //                      Otherwise from huge page TLB. The user needs to reserve
 //                      huge pages for it to be allocated, like:
 //                          sysctl -w vm.nr_hugepages=20
 //                      See linux doc Documentation/vm/hugetlbpage.txt
+// @bucket_entries_logging_threshold: if number of entries in one bucket
+//                                    exceeds this number, log about it.
+// @if_log_bucket_dist_when_flash: if true, log distribution of number of
+//                                 entries when flushing.
+// @threshold_use_skiplist: a bucket switches to skip list if number of
+//                          entries exceed this parameter.
 extern MemTableRepFactory* NewHashLinkListRepFactory(
-    size_t bucket_count = 50000, size_t huge_page_tlb_size = 0);
+    size_t bucket_count = 50000, size_t huge_page_tlb_size = 0,
+    int bucket_entries_logging_threshold = 4096,
+    bool if_log_bucket_dist_when_flash = true,
+    uint32_t threshold_use_skiplist = 256);

 // This factory creates a cuckoo-hashing based mem-table representation.
 // Cuckoo-hash is a closed-hash strategy, in which all key/value pairs
@@ -33,14 +33,13 @@ class MergeOperator;
 class Snapshot;
 class TableFactory;
 class MemTableRepFactory;
-class TablePropertiesCollector;
+class TablePropertiesCollectorFactory;
+class RateLimiter;
 class Slice;
 class SliceTransform;
 class Statistics;
 class InternalKeyComparator;

-using std::shared_ptr;
-
 // DB contents are stored in a set of blocks, each of which holds a
 // sequence of key,value pairs.  Each block may be compressed before
 // being stored in a file.  The following enum describes which
@@ -53,8 +52,18 @@ enum CompressionType : char {
 };

 enum CompactionStyle : char {
-  kCompactionStyleLevel = 0x0,     // level based compaction style
-  kCompactionStyleUniversal = 0x1  // Universal compaction style
+  kCompactionStyleLevel = 0x0,      // level based compaction style
+  kCompactionStyleUniversal = 0x1,  // Universal compaction style
+  kCompactionStyleFIFO = 0x2,       // FIFO compaction style
+};
+
+struct CompactionOptionsFIFO {
+  // once the total sum of table files reaches this, we will delete the oldest
+  // table file
+  // Default: 1GB
+  uint64_t max_table_files_size;
+
+  CompactionOptionsFIFO() : max_table_files_size(1 * 1024 * 1024 * 1024) {}
 };

 // Compression options for different compression algorithms like Zlib
@@ -73,9 +82,42 @@ enum UpdateStatus {    // Return status For inplace update callback
  UPDATED         = 2, // No inplace update. Merged value set
 };

+struct DbPath {
+  std::string path;
+  uint64_t target_size;  // Target size of total files under the path, in byte.
+
+  DbPath() : target_size(0) {}
+  DbPath(const std::string& p, uint64_t t) : path(p), target_size(t) {}
+};
+
 struct Options;

 struct ColumnFamilyOptions {
+  // Some functions that make it easier to optimize RocksDB
+
+  // Use this if you don't need to keep the data sorted, i.e. you'll never use
+  // an iterator, only Put() and Get() API calls
+  ColumnFamilyOptions* OptimizeForPointLookup();
+
+  // Default values for some parameters in ColumnFamilyOptions are not
+  // optimized for heavy workloads and big datasets, which means you might
+  // observe write stalls under some conditions. As a starting point for tuning
+  // RocksDB options, use the following two functions:
+  // * OptimizeLevelStyleCompaction -- optimizes level style compaction
+  // * OptimizeUniversalStyleCompaction -- optimizes universal style compaction
+  // Universal style compaction is focused on reducing Write Amplification
+  // Factor for big data sets, but increases Space Amplification. You can learn
+  // more about the different styles here:
+  // https://github.com/facebook/rocksdb/wiki/Rocksdb-Architecture-Guide
+  // Make sure to also call IncreaseParallelism(), which will provide the
+  // biggest performance gains.
+  // Note: we might use more memory than memtable_memory_budget during high
+  // write rate period
+  ColumnFamilyOptions* OptimizeLevelStyleCompaction(
+      uint64_t memtable_memory_budget = 512 * 1024 * 1024);
+  ColumnFamilyOptions* OptimizeUniversalStyleCompaction(
+      uint64_t memtable_memory_budget = 512 * 1024 * 1024);
+
  // -------------------
  // Parameters that affect behavior

@@ -97,7 +139,7 @@ struct ColumnFamilyOptions {
  // for the first time. It's necessary to specify a merge operator when
  // openning the DB in this case.
  // Default: nullptr
-  shared_ptr<MergeOperator> merge_operator;
+  std::shared_ptr<MergeOperator> merge_operator;

  // A single CompactionFilter instance to call into during compaction.
  // Allows an application to modify/delete a key-value during background
@@ -149,8 +191,9 @@ struct ColumnFamilyOptions {
  size_t write_buffer_size;

  // The maximum number of write buffers that are built up in memory.
-  // The default is 2, so that when 1 write buffer is being flushed to
-  // storage, new writes can continue to the other write buffer.
+  // The default and the minimum number is 2, so that when 1 write buffer
+  // is being flushed to storage, new writes can continue to the other
+  // write buffer.
  // Default: 2
  int max_write_buffer_number;

@@ -169,12 +212,12 @@ struct ColumnFamilyOptions {
  // If non-NULL use the specified cache for blocks.
  // If NULL, rocksdb will automatically create and use an 8MB internal cache.
  // Default: nullptr
-  shared_ptr<Cache> block_cache;
+  std::shared_ptr<Cache> block_cache;

  // If non-NULL use the specified cache for compressed blocks.
  // If NULL, rocksdb will not use a compressed block cache.
  // Default: nullptr
-  shared_ptr<Cache> block_cache_compressed;
+  std::shared_ptr<Cache> block_cache_compressed;

  // Approximate size of user data packed per block.  Note that the
  // block size specified here corresponds to uncompressed data.  The
@@ -332,10 +375,16 @@ struct ColumnFamilyOptions {
  // stop building a single file in a level->level+1 compaction.
  int max_grandparent_overlap_factor;

-  // Disable compaction triggered by seek.
-  // With bloomfilter and fast storage, a miss on one level
-  // is very cheap if the file handle is cached in table cache
-  // (which is true if max_open_files is large).
+  // We decided to remove seek compaction from RocksDB because:
+  // 1) It makes more sense for spinning disk workloads, while RocksDB is
+  // primarily designed for flash and memory,
+  // 2) It added some complexity to the important code-paths,
+  // 3) None of our internal customers were really using it.
+  //
+  // Since we removed seek compaction, this option is now obsolete.
+  // We left it here for backwards compatiblity (otherwise it would break the
+  // build), but we'll remove it at some point.
+  // Default: true
  bool disable_seek_compaction;

  // Puts are delayed 0-1 ms when any level has a compaction score that exceeds
@@ -403,6 +452,9 @@ struct ColumnFamilyOptions {
  // The options needed to support Universal Style compactions
  CompactionOptionsUniversal compaction_options_universal;

+  // The options for FIFO compaction style
+  CompactionOptionsFIFO compaction_options_fifo;
+
  // Use KeyMayExist API to filter deletes when this is true.
  // If KeyMayExist returns false, i.e. the key definitely does not exist, then
  // the delete is a noop. KeyMayExist only incurs in-memory look up.
@@ -429,13 +481,15 @@ struct ColumnFamilyOptions {

  // This option allows user to to collect their own interested statistics of
  // the tables.
-  // Default: emtpy vector -- no user-defined statistics collection will be
+  // Default: empty vector -- no user-defined statistics collection will be
  // performed.
-  typedef std::vector<std::shared_ptr<TablePropertiesCollector>>
-      TablePropertiesCollectors;
-  TablePropertiesCollectors table_properties_collectors;
+  typedef std::vector<std::shared_ptr<TablePropertiesCollectorFactory>>
+      TablePropertiesCollectorFactories;
+  TablePropertiesCollectorFactories table_properties_collector_factories;

-  // Allows thread-safe inplace updates.
+  // Allows thread-safe inplace updates. If this is true, there is no way to
+  // achieve point-in-time consistency using snapshot or iterator (assuming
+  // concurrent updates).
  // If inplace_callback function is not set,
  //   Put(key, new_value) will update inplace the existing_value iff
  //   * key exists in current memtable
@@ -508,12 +562,9 @@ struct ColumnFamilyOptions {

  // Control locality of bloom filter probes to improve cache miss rate.
  // This option only applies to memtable prefix bloom and plaintable
-  // prefix bloom. It essentially limits the max number of cache lines each
-  // bloom filter check can touch.
-  // This optimization is turned off when set to 0. The number should never
-  // be greater than number of probes. This option can boost performance
-  // for in-memory workload but should use with care since it can cause
-  // higher false positive rate.
+  // prefix bloom. It essentially limits every bloom checking to one cache line.
+  // This optimization is turned off when set to 0, and positive number to turn
+  // it on.
  // Default: 0
  uint32_t bloom_locality;

@@ -546,10 +597,23 @@ struct ColumnFamilyOptions {
 };

 struct DBOptions {
+  // Some functions that make it easier to optimize RocksDB
+
+  // By default, RocksDB uses only one background thread for flush and
+  // compaction. Calling this function will set it up such that total of
+  // `total_threads` is used. Good value for `total_threads` is the number of
+  // cores. You almost definitely want to call this function if your system is
+  // bottlenecked by RocksDB.
+  DBOptions* IncreaseParallelism(int total_threads = 16);
+
  // If true, the database will be created if it is missing.
  // Default: false
  bool create_if_missing;

+  // If true, missing column families will be automatically created.
+  // Default: false
+  bool create_missing_column_families;
+
  // If true, an error is raised if the database already exists.
  // Default: false
  bool error_if_exists;
@@ -570,11 +634,16 @@ struct DBOptions {
  // Default: Env::Default()
  Env* env;

+  // Use to control write rate of flush and compaction. Flush has higher
+  // priority than compaction. Rate limiting is disabled if nullptr.
+  // Default: nullptr
+  std::shared_ptr<RateLimiter> rate_limiter;
+
  // Any internal progress/error information generated by the db will
  // be written to info_log if it is non-nullptr, or to a file stored
  // in the same directory as the DB contents if info_log is nullptr.
  // Default: nullptr
-  shared_ptr<Logger> info_log;
+  std::shared_ptr<Logger> info_log;

  InfoLogLevel info_log_level;

@@ -597,7 +666,7 @@ struct DBOptions {
  // If non-null, then we should collect metrics about database operations
  // Statistics objects should not be shared between DB instances as
  // it does not use any locks to prevent concurrent updates.
-  shared_ptr<Statistics> statistics;
+  std::shared_ptr<Statistics> statistics;

  // If true, then the contents of data files are not synced
  // to stable storage. Their contents remain in the OS buffers till the
@@ -614,12 +683,35 @@ struct DBOptions {
  // Default: false
  bool use_fsync;

-  // This number controls how often a new scribe log about
-  // db deploy stats is written out.
-  // -1 indicates no logging at all.
-  // Default value is 1800 (half an hour).
+  // This options is not used!!
  int db_stats_log_interval;

+  // A list of paths where SST files can be put into, with its target size.
+  // Newer data is placed into paths specified earlier in the vector while
+  // older data gradually moves to paths specified later in the vector.
+  //
+  // For example, you have a flash device with 10GB allocated for the DB,
+  // as well as a hard drive of 2TB, you should config it to be:
+  //   [{"/flash_path", 10GB}, {"/hard_drive", 2TB}]
+  //
+  // The system will try to guarantee data under each path is close to but
+  // not larger than the target size. But current and future file sizes used
+  // by determining where to place a file are based on best-effort estimation,
+  // which means there is a chance that the actual size under the directory
+  // is slightly more than target size under some workloads. User should give
+  // some buffer room for those cases.
+  //
+  // If none of the paths has sufficient room to place a file, the file will
+  // be placed to the last path anyway, despite to the target size.
+  //
+  // Placing newer data to ealier paths is also best-efforts. User should
+  // expect user files to be placed in higher levels in some extreme cases.
+  //
+  // If left empty, only one path will be used, which is db_name passed when
+  // opening the DB.
+  // Default: empty
+  std::vector<DbPath> db_paths;
+
  // This specifies the info LOG dir.
  // If it is empty, the log files will be in the same dir as data.
  // If it is non empty, the log files will be in the specified dir,
@@ -913,7 +1005,18 @@ struct WriteOptions {
  // and the write may got lost after a crash.
  bool disableWAL;

-  WriteOptions() : sync(false), disableWAL(false) {}
+  // If non-zero, then associated write waiting longer than the specified
+  // time MAY be aborted and returns Status::TimedOut. A write that takes
+  // less than the specified time is guaranteed to not fail with
+  // Status::TimedOut.
+  //
+  // The number of times a write call encounters a timeout is recorded in
+  // Statistics.WRITE_TIMEDOUT
+  //
+  // Default: 0
+  uint64_t timeout_hint_us;
+
+  WriteOptions() : sync(false), disableWAL(false), timeout_hint_us(0) {}
 };

 // Options that control flush operations
@@ -925,6 +1028,16 @@ struct FlushOptions {
  FlushOptions() : wait(true) {}
 };

+// Get options based on some guidelines. Now only tune parameter based on
+// flush/compaction and fill default parameters for other parameters.
+// total_write_buffer_limit: budget for memory spent for mem tables
+// read_amplification_threshold: comfortable value of read amplification
+// write_amplification_threshold: comfortable value of write amplification.
+// target_db_size: estimated total DB size.
+extern Options GetOptions(size_t total_write_buffer_limit,
+                          int read_amplification_threshold = 8,
+                          int write_amplification_threshold = 32,
+                          uint64_t target_db_size = 68719476736 /* 64GB */);
 }  // namespace rocksdb

 #endif  // STORAGE_ROCKSDB_INCLUDE_OPTIONS_H_
@@ -20,6 +20,9 @@ enum PerfLevel {
 // set the perf stats level
 void SetPerfLevel(PerfLevel level);

+// get current perf stats level
+PerfLevel GetPerfLevel();
+
 // A thread local context for gathering performance counter efficiently
 // and transparently.

@@ -0,0 +1,60 @@
+//  Copyright (c) 2014, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under the BSD-style license found in the
+//  LICENSE file in the root directory of this source tree. An additional grant
+//  of patent rights can be found in the PATENTS file in the same directory.
+//
+// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file. See the AUTHORS file for names of contributors.
+
+#pragma once
+
+#include "rocksdb/env.h"
+
+namespace rocksdb {
+
+class RateLimiter {
+ public:
+  virtual ~RateLimiter() {}
+
+  // Request for token to write bytes. If this request can not be satisfied,
+  // the call is blocked. Caller is responsible to make sure
+  // bytes < GetSingleBurstBytes()
+  virtual void Request(const int64_t bytes, const Env::IOPriority pri) = 0;
+
+  // Max bytes can be granted in a single burst
+  virtual int64_t GetSingleBurstBytes() const = 0;
+
+  // Total bytes that go though rate limiter
+  virtual int64_t GetTotalBytesThrough(
+      const Env::IOPriority pri = Env::IO_TOTAL) const = 0;
+
+  // Total # of requests that go though rate limiter
+  virtual int64_t GetTotalRequests(
+      const Env::IOPriority pri = Env::IO_TOTAL) const = 0;
+};
+
+// Create a RateLimiter object, which can be shared among RocksDB instances to
+// control write rate of flush and compaction.
+// @rate_bytes_per_sec: this is the only parameter you want to set most of the
+// time. It controls the total write rate of compaction and flush in bytes per
+// second. Currently, RocksDB does not enforce rate limit for anything other
+// than flush and compaction, e.g. write to WAL.
+// @refill_period_us: this controls how often tokens are refilled. For example,
+// when rate_bytes_per_sec is set to 10MB/s and refill_period_us is set to
+// 100ms, then 1MB is refilled every 100ms internally. Larger value can lead to
+// burstier writes while smaller value introduces more CPU overhead.
+// The default should work for most cases.
+// @fairness: RateLimiter accepts high-pri requests and low-pri requests.
+// A low-pri request is usually blocked in favor of hi-pri request. Currently,
+// RocksDB assigns low-pri to request from compaciton and high-pri to request
+// from flush. Low-pri requests can get blocked if flush requests come in
+// continuouly. This fairness parameter grants low-pri requests permission by
+// 1/fairness chance even though high-pri requests exist to avoid starvation.
+// You should be good by leaving it at default 10.
+extern RateLimiter* NewGenericRateLimiter(
+    int64_t rate_bytes_per_sec,
+    int64_t refill_period_us = 100 * 1000,
+    int32_t fairness = 10);
+
+}  // namespace rocksdb
@@ -107,6 +107,7 @@ class Slice {
 struct SliceParts {
  SliceParts(const Slice* _parts, int _num_parts) :
      parts(_parts), num_parts(_num_parts) { }
+  SliceParts() : parts(nullptr), num_parts(0) {}

  const Slice* parts;
  int num_parts;
@@ -20,12 +20,12 @@ namespace rocksdb {
 *  1. Any ticker should be added before TICKER_ENUM_MAX.
 *  2. Add a readable string in TickersNameMap below for the newly added ticker.
 */
-enum Tickers {
+enum Tickers : uint32_t {
  // total block cache misses
  // REQUIRES: BLOCK_CACHE_MISS == BLOCK_CACHE_INDEX_MISS +
  //                               BLOCK_CACHE_FILTER_MISS +
  //                               BLOCK_CACHE_DATA_MISS;
-  BLOCK_CACHE_MISS,
+  BLOCK_CACHE_MISS = 0,
  // total block cache hit
  // REQUIRES: BLOCK_CACHE_HIT == BLOCK_CACHE_INDEX_HIT +
  //                              BLOCK_CACHE_FILTER_HIT +
@@ -115,9 +115,11 @@ enum Tickers {
  // head of the writers queue.
  WRITE_DONE_BY_SELF,
  WRITE_DONE_BY_OTHER,
+  WRITE_TIMEDOUT,        // Number of writes ending up with timed-out.
  WRITE_WITH_WAL,       // Number of Write calls that request WAL
  COMPACT_READ_BYTES,   // Bytes read during compaction
  COMPACT_WRITE_BYTES,  // Bytes written during compaction
+  FLUSH_WRITE_BYTES,    // Bytes written during flush

  // Number of table's properties loaded directly from file, without creating
  // table reader object.
@@ -125,6 +127,7 @@ enum Tickers {
  NUMBER_SUPERVERSION_ACQUIRES,
  NUMBER_SUPERVERSION_RELEASES,
  NUMBER_SUPERVERSION_CLEANUPS,
+  NUMBER_BLOCK_NOT_COMPRESSED,
  TICKER_ENUM_MAX
 };

@@ -175,7 +178,9 @@ const std::vector<std::pair<Tickers, std::string>> TickersNameMap = {
    {WAL_FILE_BYTES, "rocksdb.wal.bytes"},
    {WRITE_DONE_BY_SELF, "rocksdb.write.self"},
    {WRITE_DONE_BY_OTHER, "rocksdb.write.other"},
+    {WRITE_TIMEDOUT, "rocksdb.write.timedout"},
    {WRITE_WITH_WAL, "rocksdb.write.wal"},
+    {FLUSH_WRITE_BYTES, "rocksdb.flush.write.bytes"},
    {COMPACT_READ_BYTES, "rocksdb.compact.read.bytes"},
    {COMPACT_WRITE_BYTES, "rocksdb.compact.write.bytes"},
    {NUMBER_DIRECT_LOAD_TABLE_PROPERTIES,
@@ -183,6 +188,7 @@ const std::vector<std::pair<Tickers, std::string>> TickersNameMap = {
    {NUMBER_SUPERVERSION_ACQUIRES, "rocksdb.number.superversion_acquires"},
    {NUMBER_SUPERVERSION_RELEASES, "rocksdb.number.superversion_releases"},
    {NUMBER_SUPERVERSION_CLEANUPS, "rocksdb.number.superversion_cleanups"},
+    {NUMBER_BLOCK_NOT_COMPRESSED, "rocksdb.number.block.not_compressed"},
 };

 /**
@@ -192,8 +198,8 @@ const std::vector<std::pair<Tickers, std::string>> TickersNameMap = {
 * Add a string representation in HistogramsNameMap below
 * And increment HISTOGRAM_ENUM_MAX
 */
-enum Histograms {
-  DB_GET,
+enum Histograms : uint32_t {
+  DB_GET = 0,
  DB_WRITE,
  COMPACTION_TIME,
  TABLE_SYNC_MICROS,
@@ -250,14 +256,24 @@ class Statistics {
 public:
  virtual ~Statistics() {}

-  virtual long getTickerCount(Tickers tickerType) = 0;
-  virtual void recordTick(Tickers tickerType, uint64_t count = 0) = 0;
-  virtual void setTickerCount(Tickers tickerType, uint64_t count) = 0;
-  virtual void measureTime(Histograms histogramType, uint64_t time) = 0;
+  virtual uint64_t getTickerCount(uint32_t tickerType) const = 0;
+  virtual void histogramData(uint32_t type,
+                             HistogramData* const data) const = 0;
+
+  virtual void recordTick(uint32_t tickerType, uint64_t count = 0) = 0;
+  virtual void setTickerCount(uint32_t tickerType, uint64_t count) = 0;
+  virtual void measureTime(uint32_t histogramType, uint64_t time) = 0;

-  virtual void histogramData(Histograms type, HistogramData* const data) = 0;
  // String representation of the statistic object.
-  std::string ToString();
+  virtual std::string ToString() const {
+    // Do nothing by default
+    return std::string("ToString(): not implemented");
+  }
+
+  // Override this function to disable particular histogram collection
+  virtual bool HistEnabledForType(uint32_t type) const {
+    return type < HISTOGRAM_ENUM_MAX;
+  }
 };

 // Create a concrete DBStatistics object
@@ -65,6 +65,12 @@ class Status {
                                   const Slice& msg2 = Slice()) {
    return Status(kShutdownInProgress, msg, msg2);
  }
+  static Status TimedOut() {
+    return Status(kTimedOut);
+  }
+  static Status TimedOut(const Slice& msg, const Slice& msg2 = Slice()) {
+    return Status(kTimedOut, msg, msg2);
+  }

  // Returns true iff the status indicates success.
  bool ok() const { return code() == kOk; }
@@ -93,11 +99,12 @@ class Status {
  // Returns true iff the status indicates Incomplete
  bool IsShutdownInProgress() const { return code() == kShutdownInProgress; }

+  bool IsTimedOut() const { return code() == kTimedOut; }
+
  // Return a string representation of this status suitable for printing.
  // Returns the string "OK" for success.
  std::string ToString() const;

- private:
  enum Code {
    kOk = 0,
    kNotFound = 1,
@@ -107,9 +114,14 @@ class Status {
    kIOError = 5,
    kMergeInProgress = 6,
    kIncomplete = 7,
-    kShutdownInProgress = 8
+    kShutdownInProgress = 8,
+    kTimedOut = 9
  };

+  Code code() const {
+    return code_;
+  }
+ private:
  // A nullptr state_ (which is always the case for OK) means the message
  // is empty.
  // of the following form:
@@ -118,9 +130,6 @@ class Status {
  Code code_;
  const char* state_;

-  Code code() const {
-    return code_;
-  }
  explicit Status(Code code) : code_(code), state_(nullptr) { }
  Status(Code code, const Slice& msg, const Slice& msg2);
  static const char* CopyState(const char* s);
@@ -74,6 +74,12 @@ struct BlockBasedTableOptions {

  IndexType index_type = kBinarySearch;

+  // Influence the behavior when kHashSearch is used.
+  // if false, stores a precise prefix to block range mapping
+  // if true, does not store prefix and allows prefix hash collision
+  // (less memory consumption)
+  bool hash_index_allow_collision = true;
+
  // Use the specified checksum type. Newly created table files will be
  // protected with this checksum type. Old table files will still be readable,
  // even though they have different checksum type.
@@ -91,57 +97,100 @@ extern TableFactory* NewBlockBasedTableFactory(
    const BlockBasedTableOptions& table_options = BlockBasedTableOptions());

 #ifndef ROCKSDB_LITE
+
+enum EncodingType : char {
+  // Always write full keys without any special encoding.
+  kPlain,
+  // Find opportunity to write the same prefix once for multiple rows.
+  // In some cases, when a key follows a previous key with the same prefix,
+  // instead of writing out the full key, it just writes out the size of the
+  // shared prefix, as well as other bytes, to save some bytes.
+  //
+  // When using this option, the user is required to use the same prefix
+  // extractor to make sure the same prefix will be extracted from the same key.
+  // The Name() value of the prefix extractor will be stored in the file. When
+  // reopening the file, the name of the options.prefix_extractor given will be
+  // bitwise compared to the prefix extractors stored in the file. An error
+  // will be returned if the two don't match.
+  kPrefix,
+};
+
+// Table Properties that are specific to plain table properties.
+struct PlainTablePropertyNames {
+  static const std::string kPrefixExtractorName;
+  static const std::string kEncodingType;
+  static const std::string kBloomVersion;
+  static const std::string kNumBloomBlocks;
+};
+
+const uint32_t kPlainTableVariableLength = 0;
+
+struct PlainTableOptions {
+// @user_key_len: plain table has optimization for fix-sized keys, which can be
+//                specified via user_key_len.  Alternatively, you can pass
+//                `kPlainTableVariableLength` if your keys have variable
+//                lengths.
+uint32_t user_key_len = kPlainTableVariableLength;
+
+// @bloom_bits_per_key: the number of bits used for bloom filer per prefix. You
+//                      may disable it by passing a zero.
+int bloom_bits_per_key = 10;
+
+// @hash_table_ratio: the desired utilization of the hash table used for prefix
+//                    hashing. hash_table_ratio = number of prefixes / #buckets
+//                    in the hash table
+double hash_table_ratio = 0.75;
+
+// @index_sparseness: inside each prefix, need to build one index record for how
+//                    many keys for binary search inside each hash bucket.
+//                    For encoding type kPrefix, the value will be used when
+//                    writing to determine an interval to rewrite the full key.
+//                    It will also be used as a suggestion and satisfied when
+//                    possible.
+size_t index_sparseness = 16;
+
+// @huge_page_tlb_size: if <=0, allocate hash indexes and blooms from malloc.
+//                      Otherwise from huge page TLB. The user needs to reserve
+//                      huge pages for it to be allocated, like:
+//                          sysctl -w vm.nr_hugepages=20
+//                      See linux doc Documentation/vm/hugetlbpage.txt
+size_t huge_page_tlb_size = 0;
+
+// @encoding_type: how to encode the keys. See enum EncodingType above for
+//                 the choices. The value will determine how to encode keys
+//                 when writing to a new SST file. This value will be stored
+//                 inside the SST file which will be used when reading from the
+//                 file, which makes it possible for users to choose different
+//                 encoding type when reopening a DB. Files with different
+//                 encoding types can co-exist in the same DB and can be read.
+EncodingType encoding_type = kPlain;
+
+// @full_scan_mode: mode for reading the whole file one record by one without
+//                  using the index.
+  bool full_scan_mode = false;
+
+  // @store_index_in_file: compute plain table index and bloom filter during
+  //                       file building and store it in file. When reading
+  //                       file, index will be mmaped instead of recomputation.
+  bool store_index_in_file = false;
+};
+
 // -- Plain Table with prefix-only seek
 // For this factory, you need to set Options.prefix_extrator properly to make it
 // work. Look-up will starts with prefix hash lookup for key prefix. Inside the
 // hash bucket found, a binary search is executed for hash conflicts. Finally,
 // a linear search is used.
-// @user_key_len: plain table has optimization for fix-sized keys, which can be
-//                specified via user_key_len.  Alternatively, you can pass
-//                `kPlainTableVariableLength` if your keys have variable
-//                lengths.
-// @bloom_bits_per_key: the number of bits used for bloom filer per prefix. You
-//                      may disable it by passing a zero.
-// @hash_table_ratio: the desired utilization of the hash table used for prefix
-//                    hashing. hash_table_ratio = number of prefixes / #buckets
-//                    in the hash table
-// @index_sparseness: inside each prefix, need to build one index record for how
-//                    many keys for binary search inside each hash bucket.
-// @huge_page_tlb_size: if <=0, allocate hash indexes and blooms from malloc.
-//                      Otherwise from huge page TLB. The user needs to reserve
-//                      huge pages for it to be allocated, like:
-//                          sysctl -w vm.nr_hugepages=20
-//                      See linux doc Documentation/vm/hugetlbpage.txt

-const uint32_t kPlainTableVariableLength = 0;
-extern TableFactory* NewPlainTableFactory(uint32_t user_key_len =
-                                              kPlainTableVariableLength,
-                                          int bloom_bits_per_prefix = 10,
-                                          double hash_table_ratio = 0.75,
-                                          size_t index_sparseness = 16,
-                                          size_t huge_page_tlb_size = 0);
+extern TableFactory* NewPlainTableFactory(const PlainTableOptions& options =
+                                              PlainTableOptions());

-// -- Plain Table
-// This factory of plain table ignores Options.prefix_extractor and assumes no
-// hashable prefix available to the key structure. Lookup will be based on
-// binary search index only. Total order seek() can be issued.
-// @user_key_len: plain table has optimization for fix-sized keys, which can be
-//                specified via user_key_len.  Alternatively, you can pass
-//                `kPlainTableVariableLength` if your keys have variable
-//                lengths.
-// @bloom_bits_per_key: the number of bits used for bloom filer per key. You may
-//                  disable it by passing a zero.
-// @index_sparseness: need to build one index record for how many keys for
-//                    binary search.
-// @huge_page_tlb_size: if <=0, allocate hash indexes and blooms from malloc.
-//                      Otherwise from huge page TLB. The user needs to reserve
-//                      huge pages for it to be allocated, like:
-//                          sysctl -w vm.nr_hugepages=20
-//                      See linux doc Documentation/vm/hugetlbpage.txt
-extern TableFactory* NewTotalOrderPlainTableFactory(
-    uint32_t user_key_len = kPlainTableVariableLength,
-    int bloom_bits_per_key = 0, size_t index_sparseness = 16,
-    size_t huge_page_tlb_size = 0);
+struct CuckooTablePropertyNames {
+  static const std::string kEmptyKey;
+  static const std::string kValueLength;
+  static const std::string kNumHashTable;
+  static const std::string kMaxNumBuckets;
+  static const std::string kIsLastLevel;
+};

 #endif  // ROCKSDB_LITE

@@ -203,4 +252,19 @@ class TableFactory {
      WritableFile* file, CompressionType compression_type) const = 0;
 };

+#ifndef ROCKSDB_LITE
+// Create a special table factory that can open both of block based table format
+// and plain table, based on setting inside the SST files. It should be used to
+// convert a DB from one table format to another.
+// @table_factory_to_write: the table factory used when writing to new files.
+// @block_based_table_factory:  block based table factory to use. If NULL, use
+//                              a default one.
+// @plain_table_factory: plain table factory to use. If NULL, use a default one.
+extern TableFactory* NewAdaptiveTableFactory(
+    std::shared_ptr<TableFactory> table_factory_to_write = nullptr,
+    std::shared_ptr<TableFactory> block_based_table_factory = nullptr,
+    std::shared_ptr<TableFactory> plain_table_factory = nullptr);
+
+#endif  // ROCKSDB_LITE
+
 }  // namespace rocksdb
@@ -79,7 +79,10 @@ extern const std::string kPropertiesBlock;

 // `TablePropertiesCollector` provides the mechanism for users to collect
 // their own interested properties. This class is essentially a collection
-//  of callback functions that will be invoked during table building.
+// of callback functions that will be invoked during table building.
+// It is construced with TablePropertiesCollectorFactory. The methods don't
+// need to be thread-safe, as we will create exactly one
+// TablePropertiesCollector object per table and then call it sequentially
 class TablePropertiesCollector {
 public:
  virtual ~TablePropertiesCollector() {}
@@ -95,12 +98,24 @@ class TablePropertiesCollector {
  // `properties`.
  virtual Status Finish(UserCollectedProperties* properties) = 0;

-  // The name of the properties collector can be used for debugging purpose.
-  virtual const char* Name() const = 0;
-
  // Return the human-readable properties, where the key is property name and
  // the value is the human-readable form of value.
  virtual UserCollectedProperties GetReadableProperties() const = 0;
+
+  // The name of the properties collector can be used for debugging purpose.
+  virtual const char* Name() const = 0;
+};
+
+// Constructs TablePropertiesCollector. Internals create a new
+// TablePropertiesCollector for each new table
+class TablePropertiesCollectorFactory {
+ public:
+  virtual ~TablePropertiesCollectorFactory() {}
+  // has to be thread-safe
+  virtual TablePropertiesCollector* CreateTablePropertiesCollector() = 0;
+
+  // The name of the properties collector can be used for debugging purpose.
+  virtual const char* Name() const = 0;
 };

 // Extra properties
				`@@ -0,0 +1 @@`
				Compile RocksDB first by executing `make static_lib` in parent dir