A library that provides an embeddable, persistent key-value store for fast storage.
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Zhichao Cao cddd637997 Merge adjacent file block reads in RocksDB MultiGet() and Add uncompressed block to cache (#6089)
Summary:
In the current MultiGet, if the KV-pairs do not belong to the data blocks in the block cache, multiple blocks are read from a SST. It will trigger one block read for each block request and read them in parallel. In some cases, if some data blocks are adjacent in the SST, the reads for these blocks can be combined to a single large read, which can reduce the system calls and reduce the read latency if possible.

Considering to fill the block cache, if multiple data blocks are in the same memory buffer, we need to copy them to the heap separately. Therefore, only in the case that 1) data block compression is enabled, and 2) compressed block cache is null, we can do combined read. Otherwise, extra memory copy is needed, which may cause extra overhead. In the current case, data blocks will be uncompressed to a new memory space.

Also, in the case that 1) data block compression is enabled, and 2) compressed block cache is null, it is possible the data block is actually not compressed. In the current logic, these data blocks will not be added to the uncompressed_cache. So if memory buffer is shared and the data block is not compressed, the data block are copied to the head and fill the cache.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6089

Test Plan: Added test case to ParallelIO.MultiGet. Pass make asan_check

Differential Revision: D18734668

Pulled By: zhichao-cao

fbshipit-source-id: 67c5615ed373e51e42635fd74b36f8f3a66d5da4
2019-12-16 16:26:03 -08:00
buckifier PosixRandomAccessFile::MultiRead() to use I/O uring if supported (#5881) 2019-12-07 20:55:52 -08:00
build_tools Improve instructions to install formatter (#6162) 2019-12-12 14:04:01 -08:00
cache Remove key length assertion LRUHandle::CalcTotalCharge (#6115) 2019-12-02 15:00:07 -08:00
cmake cmake: do not build tests for Release build and cleanups (#5916) 2019-12-13 12:48:06 -08:00
coverage Fix interpreter lines for files with python2-only syntax. 2019-07-09 10:51:37 -07:00
db Merge adjacent file block reads in RocksDB MultiGet() and Add uncompressed block to cache (#6089) 2019-12-16 16:26:03 -08:00
db_stress_tool Add some new options to crash_test (#6176) 2019-12-16 15:43:13 -08:00
docs Blog post for write_unprepared (#5711) 2019-08-15 14:41:13 -07:00
env Fix unity test (#6178) 2019-12-14 15:39:41 -08:00
examples Add example to show the effect of Get in snapshot isolation (#6059) 2019-12-11 09:56:42 -08:00
file Introduce a new storage specific Env API (#5761) 2019-12-13 14:48:41 -08:00
hdfs Add copyright headers per FB open-source checkup tool. (#5199) 2019-04-18 10:55:01 -07:00
include/rocksdb Introduce a new storage specific Env API (#5761) 2019-12-13 14:48:41 -08:00
java Env should also load the native library (#6167) 2019-12-13 16:27:55 -08:00
logging Introduce a new storage specific Env API (#5761) 2019-12-13 14:48:41 -08:00
memory Charge block cache for cache internal usage (#5797) 2019-09-16 15:26:21 -07:00
memtable Misc hashing updates / upgrades (#5909) 2019-10-24 17:16:46 -07:00
monitoring Apply formatter to recent 200+ commits. (#5830) 2019-09-20 12:04:26 -07:00
options Introduce a new storage specific Env API (#5761) 2019-12-13 14:48:41 -08:00
port Work around weird unused errors with Mingw (#6075) 2019-11-26 21:42:29 -08:00
table Merge adjacent file block reads in RocksDB MultiGet() and Add uncompressed block to cache (#6089) 2019-12-16 16:26:03 -08:00
test_util Introduce a new storage specific Env API (#5761) 2019-12-13 14:48:41 -08:00
third-party Apply formatter to some recent commits (#6138) 2019-12-09 15:49:49 -08:00
tools Add some new options to crash_test (#6176) 2019-12-16 15:43:13 -08:00
trace_replay Misc hashing updates / upgrades (#5909) 2019-10-24 17:16:46 -07:00
util Optimize memory and CPU for building new Bloom filter (#6175) 2019-12-15 21:31:08 -08:00
utilities Make it possible to enable periodic compactions for BlobDB (#6172) 2019-12-13 16:13:25 -08:00
.clang-format A script that automatically reformat affected lines 2014-01-14 12:21:24 -08:00
.gitignore Make buckifier python3 compatible (#5922) 2019-10-23 13:52:27 -07:00
.lgtm.yml Create lgtm.yml for LGTM.com C/C++ analysis (#4058) 2018-06-26 12:43:04 -07:00
.travis.yml cmake: do not build tests for Release build and cleanups (#5916) 2019-12-13 12:48:06 -08:00
.watchmanconfig Added .watchmanconfig file to rocksdb repo (#5593) 2019-07-19 15:00:33 -07:00
appveyor.yml Add Visual Studio 2015 to AppVeyor (#5446) 2019-12-10 20:02:31 -08:00
AUTHORS Update RocksDB Authors File 2017-10-18 14:42:10 -07:00
CMakeLists.txt Introduce a new storage specific Env API (#5761) 2019-12-13 14:48:41 -08:00
CODE_OF_CONDUCT.md Adopt Contributor Covenant 2019-08-29 23:21:01 -07:00
CONTRIBUTING.md Add Code of Conduct 2017-12-05 18:42:35 -08:00
COPYING Add GPLv2 as an alternative license. 2017-04-27 18:06:12 -07:00
DEFAULT_OPTIONS_HISTORY.md options.delayed_write_rate use the rate of rate_limiter by default. 2017-05-24 09:58:24 -07:00
defs.bzl Add clarifying/instructive header to TARGETS and defs.bzl 2019-11-05 20:20:33 -08:00
DUMP_FORMAT.md First version of rocksdb_dump and rocksdb_undump. 2015-06-19 16:24:36 -07:00
HISTORY.md Update HISTORY.md with the recent memtable trimming fixes 2019-12-16 15:19:52 -08:00
INSTALL.md Update the version of the dependencies used by the RocksJava static build (#4761) 2018-12-18 20:25:43 -08:00
issue_template.md Add a template for issues 2017-09-29 11:41:28 -07:00
LANGUAGE-BINDINGS.md LANGUAGE-BINDINGS.md: mention python-rocksdb 2019-03-20 11:10:48 -07:00
LICENSE.Apache Change RocksDB License 2017-07-15 16:11:23 -07:00
LICENSE.leveldb Add back the LevelDB license file 2017-07-16 18:42:18 -07:00
Makefile Add useful idioms to Random API (OneInOpt, PercentTrue) (#6154) 2019-12-13 14:30:14 -08:00
README.md Replaced some words (#5877) 2019-10-07 12:28:09 -07:00
ROCKSDB_LITE.md Fix some typos in comments and docs. 2018-03-08 10:27:25 -08:00
src.mk Introduce a new storage specific Env API (#5761) 2019-12-13 14:48:41 -08:00
TARGETS Introduce a new storage specific Env API (#5761) 2019-12-13 14:48:41 -08:00
thirdparty.inc Fix build jemalloc api (#5470) 2019-06-24 17:40:32 -07:00
USERS.md Add avrio to USERS.md (#5748) 2019-09-15 21:29:09 -07:00
Vagrantfile Adding CentOS 7 Vagrantfile & build script 2018-02-26 15:27:17 -08:00
WINDOWS_PORT.md #5145 , rename port/dirent.h to port/port_dirent.h to avoid compile err when use port dir as header dir output (#5152) 2019-04-04 11:38:19 -07:00

RocksDB: A Persistent Key-Value Store for Flash and RAM Storage

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RocksDB is developed and maintained by Facebook Database Engineering Team. It is built 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 especially 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 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/

License

RocksDB is dual-licensed under both the GPLv2 (found in the COPYING file in the root directory) and Apache 2.0 License (found in the LICENSE.Apache file in the root directory). You may select, at your option, one of the above-listed licenses.