00ee89b584
Summary: There are some tricky behaviors related to WAL sync: - When creating a WAL, the WAL might not be synced, if the WAL directory is not synced, the WAL file's metadata may not even be synced to disk, so during recovery, when listing the WAL directory, the WAL may not even show up. - During each DB::Write, the WriteOption can control whether the WAL should be synced, so a WAL previously not synced on creation can be synced during Write. For each `SyncWAL`, we'll track the synced status and the current WAL size. Previously, we only track the WAL size on closing. During recovery, we check that the on-disk WAL size is >= the last synced size. So this PR introduces `synced_size` and `closed` to `WalMetadata` for the above design update. Pull Request resolved: https://github.com/facebook/rocksdb/pull/7414 Test Plan: - updated wal_edit_test - updated version_edit_test Reviewed By: riversand963 Differential Revision: D23796127 Pulled By: cheng-chang fbshipit-source-id: 5498ab80f537c48a10157e71a4745716aef5cf30
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.