88e0527724
Summary: Based on https://github.com/facebook/rocksdb/issues/843 It looks that when the data is hot we spend significant amount of time moving data out of RocksDB blocks. This patch reduce moving memory when possible Original performance ``` $ time ./ldb --db=/home/tec/local/ellina_test/testdb scan > /dev/null real 0m16.736s user 0m11.993s sys 0m4.725s ``` Performance after reducing memcpy ``` $ time ./ldb --db=/home/tec/local/ellina_test/testdb scan > /dev/null real 0m11.590s user 0m6.983s sys 0m4.595s ``` Test Plan: dump the output of the scan into 2 files and verifying the are exactly the same make check Reviewers: sdong, yhchiang, anthony, rven, igor Reviewed By: igor Subscribers: dhruba Differential Revision: https://reviews.facebook.net/D51093
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/