A library that provides an embeddable, persistent key-value store for fast storage.
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Jay Edgar efd013d6d8 Miscellaneous performance improvements
Summary:
I was investigating performance issues in the SstFileWriter and found all of the following:

- The SstFileWriter::Add() function created a local InternalKey every time it was called generating a allocation and free each time.  Changed to have an InternalKey member variable that can be reset with the new InternalKey::Set() function.
- In SstFileWriter::Add() the smallest_key and largest_key values were assigned the result of a ToString() call, but it is simpler to just assign them directly from the user's key.
- The Slice class had no move constructor so each time one was returned from a function a new one had to be allocated, the old data copied to the new, and the old one was freed.  I added the move constructor which also required a copy constructor and assignment operator.
- The BlockBuilder::CurrentSizeEstimate() function calculates the current estimate size, but was being called 2 or 3 times for each key added.  I changed the class to maintain a running estimate (equal to the original calculation) so that the function can return an already calculated value.
- The code in BlockBuilder::Add() that calculated the shared bytes between the last key and the new key duplicated what Slice::difference_offset does, so I replaced it with the standard function.
- BlockBuilder::Add() had code to copy just the changed portion into the last key value (and asserted that it now matched the new key).  It is more efficient just to copy the whole new key over.
- Moved this same code up into the 'if (use_delta_encoding_)' since the last key value is only needed when delta encoding is on.
- FlushBlockBySizePolicy::BlockAlmostFull calculated a standard deviation value each time it was called, but this information would only change if block_size of block_size_deviation changed, so I created a member variable to hold the value to avoid the calculation each time.
- Each PutVarint??() function has a buffer and calls std::string::append().  Two or three calls in a row could share a buffer and a single call to std::string::append().

Some of these will be helpful outside of the SstFileWriter.  I'm not 100% the addition of the move constructor is appropriate as I wonder why this wasn't done before - maybe because of compiler compatibility?  I tried it on gcc 4.8 and 4.9.

Test Plan: The changes should not affect the results so the existing tests should all still work and no new tests were added.  The value of the changes was seen by manually testing the SstFileWriter class through MyRocks and adding timing code to identify problem areas.

Reviewers: sdong, IslamAbdelRahman

Reviewed By: IslamAbdelRahman

Subscribers: andrewkr, dhruba

Differential Revision: https://reviews.facebook.net/D59607
2016-07-12 14:15:32 -07:00
arcanist_util Add release build to RocksDB per-diff/post-commit tests 2016-07-08 16:02:29 -07:00
build_tools Add release build to RocksDB per-diff/post-commit tests 2016-07-08 16:02:29 -07:00
coverage Fix coverage script 2014-11-03 14:53:00 -08:00
db Miscellaneous performance improvements 2016-07-12 14:15:32 -07:00
doc Lint everything 2015-11-16 12:56:21 -08:00
examples Fix examples/Makefile jemalloc error 2016-06-14 12:18:32 -07:00
hdfs using java7 in runtime for hdfs env (#1072) 2016-04-12 00:08:26 -04:00
include/rocksdb Fix Log() doc for default level 2016-07-11 11:16:53 -07:00
java Add options.write_buffer_manager: control total memtable size across DB instances 2016-07-05 18:11:25 -07:00
memtable Updated all copyright headers to the new format. 2016-02-09 15:12:00 -08:00
port stack_trace,cc: The current Stacktrace code does not compile for FreeBSD (#1153) 2016-06-05 17:40:43 -07:00
table Miscellaneous performance improvements 2016-07-12 14:15:32 -07:00
third-party Fix clang analyzer errors 2016-07-08 17:50:51 -07:00
tools Fix clang analyzer errors 2016-07-08 17:50:51 -07:00
util Miscellaneous performance improvements 2016-07-12 14:15:32 -07:00
utilities Fix clang analyzer errors 2016-07-08 17:50:51 -07:00
.arcconfig Integrate Jenkins with Phabricator 2015-04-07 11:56:29 -07:00
.clang-format A script that automatically reformat affected lines 2014-01-14 12:21:24 -08:00
.gitignore Ignore db_test2 2016-03-07 15:56:16 -08:00
.travis.yml Re-enable linux on travis 2016-06-30 14:34:50 -07:00
appveyor.yml Disable long running GroupCommitTest (#1125) 2016-05-19 10:29:49 -07:00
AUTHORS Add AUTHORS file. Fix #203 2014-09-29 10:52:18 -07:00
CMakeLists.txt Fixed Minor Bug on Windows Build and db_bench_tool.cc (#1189) 2016-06-29 18:44:22 -07:00
CONTRIBUTING.md facebook accounts are not required for CLA signers 2014-07-08 05:57:54 -04:00
DEFAULT_OPTIONS_HISTORY.md Release RocksDB 4.8.0 2016-05-02 14:38:04 -07:00
DUMP_FORMAT.md First version of rocksdb_dump and rocksdb_undump. 2015-06-19 16:24:36 -07:00
HISTORY.md Add options.write_buffer_manager: control total memtable size across DB instances 2016-07-05 18:11:25 -07:00
INSTALL.md Simple changes to support builds for ppc64[le] consistent with X86 2016-01-19 09:08:19 -06:00
LANGUAGE-BINDINGS.md Merge pull request #1056 from facebook/igorcanadi-patch-1 2016-04-04 08:08:52 -07:00
LICENSE Updated all copyright headers to the new format. 2016-02-09 15:12:00 -08:00
Makefile Update Makefile to fix dependency 2016-07-11 13:55:46 -07:00
PATENTS Update Patent Grant. 2015-04-13 10:33:43 +01:00
README.md Replaced "built on on earlier work" by "built on earlier work" in README.md 2014-09-17 01:16:17 -07:00
ROCKSDB_LITE.md Optimistic Transactions 2015-05-29 14:36:35 -07:00
src.mk Update Makefile to fix dependency 2016-07-11 13:55:46 -07:00
thirdparty.inc Introduce XPRESS compresssion on Windows. (#1081) 2016-04-19 22:54:24 -07:00
USERS.md Update USER.md to include more services at Facebook. 2016-07-06 14:27:08 -07:00
Vagrantfile RocksDB on FreeBSD support 2015-02-26 15:19:17 -08:00
WINDOWS_PORT.md Commit both PR and internal code review changes 2015-07-07 16:58:20 -07:00

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

Build Status

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 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 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/