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A library that provides an embeddable, persistent key-value store for fast storage.
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4a21b1402c
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Islam AbdelRahman 4a21b1402c Cache heap::downheap() root comparison (optimize heap cmp call) 
Summary:
Reduce number of comparisons in heap by caching which child node in the first level is smallest (left_child or right_child)
So next time we can compare directly against the smallest child

I see that the total number of calls to comparator drops significantly when using this optimization

Before caching (~2mil key comparison for iterating the DB)
```
$ DEBUG_LEVEL=0 make db_bench -j64 && ./db_bench --benchmarks="readseq" --db="/dev/shm/heap_opt" --use_existing_db --disable_auto_compactions --cache_size=1000000000  --perf_level=2
readseq      :       0.338 micros/op 2959201 ops/sec;  327.4 MB/s user_key_comparison_count = 2000008
```
After caching (~1mil key comparison for iterating the DB)
```
$ DEBUG_LEVEL=0 make db_bench -j64 && ./db_bench --benchmarks="readseq" --db="/dev/shm/heap_opt" --use_existing_db --disable_auto_compactions --cache_size=1000000000 --perf_level=2
readseq      :       0.309 micros/op 3236801 ops/sec;  358.1 MB/s user_key_comparison_count = 1000011
```

It also improves
Closes https://github.com/facebook/rocksdb/pull/1600

Differential Revision: D4256027

Pulled By: IslamAbdelRahman

fbshipit-source-id: 76fcc66
2016-12-01 13:39:14 -08:00
arcanist_util Rocksdb contruns to new Sandcastle API 2016-11-10 10:54:20 -08:00
build_tools pass rocksdb oncall to mysql_mtr_filter otherwise tasks get created w… 2016-11-29 12:09:12 -08:00
cmake/modules cmake support for linux and osx (#1358) 2016-09-28 11:53:15 -07:00
coverage Fix coverage script 2014-11-03 14:53:00 -08:00
db Fix travis (compile for clang < 3.9) 2016-12-01 10:09:22 -08:00
docs Reword support a little bit to more clear and concise 2016-11-21 11:39:13 -08:00
examples Fix failed compaction_filter_example and add it into make all 2016-11-15 17:09:10 -08:00
hdfs Fix bug in UnScSigned-off-by: xh931076284 <931076284@qq.com> (#1336) 2016-09-14 10:17:34 -07:00
include/rocksdb Kill flashcache code in RocksDB 2016-12-01 10:09:22 -08:00
java Remove Ticker::SEQUENCE_NUMBER 2016-11-16 22:39:09 -08:00
memtable Unified InlineSkipList::Insert algorithm with hinting 2016-11-22 14:09:13 -08:00
port Fix integer overflow in GetL0ThresholdSpeedupCompaction (#1378) 2016-10-23 18:43:29 -07:00
table Range deletion microoptimizations 2016-11-21 12:24:13 -08:00
third-party Kill flashcache code in RocksDB 2016-12-01 10:09:22 -08:00
tools Cache heap::downheap() root comparison (optimize heap cmp call) 2016-12-01 13:39:14 -08:00
util Cache heap::downheap() root comparison (optimize heap cmp call) 2016-12-01 13:39:14 -08:00
utilities Fix travis (compile for clang < 3.9) 2016-12-01 10:09:22 -08:00
.arcconfig Make rocksdb work with internal repo 2016-10-28 14:59:50 -07:00
.clang-format A script that automatically reformat affected lines 2014-01-14 12:21:24 -08:00
.gitignore Less linear search in DBIter::Seek() when keys are overwritten a lot 2016-11-28 10:24:11 -08:00
.travis.yml Ask travis to use JDK 7 2016-11-16 10:54:12 -08:00
appveyor.yml fix vs generator (#1269) 2016-08-10 09:08:13 -07:00
AUTHORS Add AUTHORS file. Fix #203 2014-09-29 10:52:18 -07:00
CMakeLists.txt Kill flashcache code in RocksDB 2016-12-01 10:09:22 -08:00
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 Kill flashcache code in RocksDB 2016-12-01 10:09:22 -08:00
INSTALL.md Update documentation to point at gcc 4.8 2016-10-29 12:09:17 -07:00
LANGUAGE-BINDINGS.md Update LANGUAGE-BINDINGS.md 2016-07-15 13:09:30 +02:00
LICENSE Updated all copyright headers to the new format. 2016-02-09 15:12:00 -08:00
Makefile DeleteRange write path end-to-end tests 2016-11-29 11:09:22 -08:00
PATENTS Update Patent Grant. 2015-04-13 10:33:43 +01:00
README.md Appveyor badge to show master branch 2016-07-26 13:54:08 -07:00
ROCKSDB_LITE.md Optimistic Transactions 2015-05-29 14:36:35 -07:00
src.mk Kill flashcache code in RocksDB 2016-12-01 10:09:22 -08:00
thirdparty.inc Introduce XPRESS compresssion on Windows. (#1081) 2016-04-19 22:54:24 -07:00
USERS.md Adding Dgraph to list of Users (#1291) 2016-09-12 17:33:44 -07:00
Vagrantfile Update Vagrant file (test internal phabricator workflow) 2016-10-28 15:39:19 -07:00
WINDOWS_PORT.md Commit both PR and internal code review changes 2015-07-07 16:58:20 -07:00

README.md

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

Build Status 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/