b9d65f5aa6
Summary: In level compaction, if the total size (even if compensated after taking account of the deletions) of a level hasn't exceeded the limit, but there are lots of deletion entries in some SST files of the level, these files should also be good candidates for compaction. Otherwise, queries for the deleted keys might be slow because they need to go over all the tombstones. This PR adds an option `deletion_ratio` to the factory of `CompactOnDeletionCollector` to configure it to trigger compaction when the ratio of tombstones >= `deletion_ratio`. Pull Request resolved: https://github.com/facebook/rocksdb/pull/6806 Test Plan: Added new unit test in `compact_on_deletion_collector_test.cc`. make compact_on_deletion_collector_test && ./compact_on_deletion_collector_test Reviewed By: ajkr Differential Revision: D21511981 Pulled By: cheng-chang fbshipit-source-id: 65a9d0150e8c9c00337787686475252e4535a3e1
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.