ab202e8d72
Summary: Currently, application may pass a statistics object to db but later wants to reduce stats tracking overhead by setting stats level to kExceptHistogramOrTimers (the current lowest level). Tickers will still be incremented, causing up to 1% CPU. We can add a new lowest stats level `kExceptTickers` to disable ticker incrementing as well, thus reducing CPU cycles spent on tickers. Test Plan (devserver): ``` make check make clean DEBUG_LEVEL=0 make db_bench ./db_bench -perf_level=1 -stats_level=0 -statistics -benchmarks=fillseq,readrandom -duration=120 ``` Measure CPU util (%) before and after change: CPU util by rocksdb::RecordTick: 1.1 vs (<0.1) Pull Request resolved: https://github.com/facebook/rocksdb/pull/7329 Reviewed By: pdillinger Differential Revision: D23434014 Pulled By: riversand963 fbshipit-source-id: 72ff0f02a192ac476d4b0044b9f37fd4a22ff0d4
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 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/ and https://rocksdb.slack.com/
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.