51c8841418
Summary: In dictionary compression's initial implementation, in order to save CPU overhead, we only enabled it for bottom level under the assumption that the vast majority of data is stored there. At that time, there was no such thing as `ColumnFamilyOptions::bottommost_compression_opts`, so we just hardcoded disabling dictionary compression in flush and compactions to non-bottommost level. Now, we have users who generate all their files through flush and are considering using dictionary compression. To support such a use case, this PR expands the scope of `ColumnFamilyOptions::compression_opts` to additionally include flushed files and files generated by compaction to a non-bottommost level. Users can still get the old behavior by moving their dictionary settings to `ColumnFamilyOptions::bottommost_compression_opts` and explicitly enabling both that and `ColumnFamilyOptions::bottommost_compression`. Pull Request resolved: https://github.com/facebook/rocksdb/pull/7619 Reviewed By: ltamasi Differential Revision: D24665610 Pulled By: ajkr fbshipit-source-id: 656b90bce1033fe21c71e09af931ef5bde3e464c
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.