1613fa9490
Summary: To reduce contention for atomics when HistogramStats are shared across threads, this diff makes them thread-specific so updates are faster. This comes at the expense of slower reads (much less frequent), which now require merging all histograms. In this diff, - Thread-specific HistogramImpl is created upon the thread's first measureTime() - Thread-specific HistogramImpl are merged and deleted upon thread termination or ThreadLocalPtr destruction, whichever comes first - getHistogramString() and histogramData() merge all histograms, both thread-specific and previously merged ones Test Plan: unit tests, ran db_bench and verified histograms look similar before: $ TEST_TMPDIR=/dev/shm/ perf record -g ./db_bench --benchmarks=readwhilewriting --statistics --num=1000000 --use_existing_db --threads=64 --cache_size=250000000 --compression_type=lz4 ... + 7.63% db_bench db_bench [.] rocksdb::HistogramStat::Add after: $ TEST_TMPDIR=/dev/shm/ perf record -g ./db_bench --benchmarks=readwhilewriting --statistics --num=1000000 --use_existing_db --threads=64 --cache_size=250000000 --compression_type=lz4 ... + 0.98% db_bench db_bench [.] rocksdb::HistogramStat::Add Reviewers: sdong, MarkCallaghan, kradhakrishnan, IslamAbdelRahman Reviewed By: IslamAbdelRahman Subscribers: andrewkr, dhruba, leveldb Differential Revision: https://reviews.facebook.net/D62649 |
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| arcanist_util | ||
| build_tools | ||
| coverage | ||
| db | ||
| doc | ||
| docs | ||
| examples | ||
| hdfs | ||
| include/rocksdb | ||
| java | ||
| memtable | ||
| port | ||
| table | ||
| third-party | ||
| tools | ||
| util | ||
| utilities | ||
| .arcconfig | ||
| .clang-format | ||
| .gitignore | ||
| .travis.yml | ||
| appveyor.yml | ||
| AUTHORS | ||
| CMakeLists.txt | ||
| CONTRIBUTING.md | ||
| DEFAULT_OPTIONS_HISTORY.md | ||
| DUMP_FORMAT.md | ||
| HISTORY.md | ||
| INSTALL.md | ||
| LANGUAGE-BINDINGS.md | ||
| LICENSE | ||
| Makefile | ||
| PATENTS | ||
| README.md | ||
| ROCKSDB_LITE.md | ||
| src.mk | ||
| thirdparty.inc | ||
| USERS.md | ||
| Vagrantfile | ||
| WINDOWS_PORT.md | ||
RocksDB: A Persistent Key-Value Store for Flash and RAM Storage
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/