1d20fa9d0f
Summary: MergeUntil was not reporting a success when merging an operand with a Value/Deletion despite the comments in MergeHelper and CompactionJob indicating otherwise. This lead to operands being written to the compaction output unnecessarily: M1 M2 M3 P M4 M5 --> (P+M1+M2+M3) M2 M3 M4 M5 (before the diff) M1 M2 M3 P M4 M5 --> (P+M1+M2+M3) M4 M5 (after the diff) In addition, the code handling Values/Deletion was basically identical. This patch unifies the code. Finally, this patch also adds testing for merge_helper. Test Plan: make && make check Reviewers: sdong, rven, yhchiang, tnovak, igor Reviewed By: igor Subscribers: tnovak, dhruba, leveldb Differential Revision: https://reviews.facebook.net/D42351
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/