d854abad78
Summary: https://github.com/facebook/rocksdb/pull/6901 subtly changed the handling of the corner case when a table file is deleted from a level, then re-added to the same level. (Note: this should be extremely rare; one scenario that comes to mind is a trivial move followed by a call to `ReFitLevel` that moves the file back to the original level.) Before that change, a new `FileMetaData` object was created as a result of this sequence; after the change, the original `FileMetaData` was essentially resurrected (since the deletion and the addition simply cancel each other out with the change). This patch restores the original behavior, which is more intuitive considering the interface, and in sync with how trivial moves are handled. (Also note that `FileMetaData` contains some mutable data members, the values of which might be different in the resurrected object and the freshly created one.) The PR also fixes a bug in this area: with the original pre-6901 code, `VersionBuilder` would add the same file twice to the same level in the scenario described above. Pull Request resolved: https://github.com/facebook/rocksdb/pull/6939 Test Plan: `make check` Reviewed By: ajkr Differential Revision: D21905580 Pulled By: ltamasi fbshipit-source-id: da07ae45384ecf3c6c53506d106432d88a7ec9df
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.