e813f5b6d9
Summary: This diff allows compaction to reclaim storage more effectively. In the current design, compactions are mainly triggered based on the file sizes. However, since deletion entries does not have value, files which have many deletion entries are less likely to be compacted. As a result, it may took a while to make deletion entries to be compacted. This diff address issue by compensating the size of deletion entries during compaction process: the size of each deletion entry in the compaction process is augmented by 2x average value size. The diff applies to both leveled and universal compacitons. Test Plan: develop CompactionDeletionTrigger make db_test ./db_test Reviewers: haobo, igor, ljin, sdong Reviewed By: sdong Subscribers: leveldb Differential Revision: https://reviews.facebook.net/D19029
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 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/