0c6e4674a6
Summary: Historically, the DB properties `rocksdb.cur-size-active-mem-table`, `rocksdb.cur-size-all-mem-tables`, and `rocksdb.size-all-mem-tables` called the method `MemTable::ApproximateMemoryUsage` for mutable memtables, which is not safe without synchronization. This resulted in data races with memtable inserts. The patch changes the code handling these properties to use `MemTable::ApproximateMemoryUsageFast` instead, which returns a cached value backed by an atomic variable. Two test cases had to be updated for this change. `MemoryTest.MemTableAndTableReadersTotal` was fixed by increasing the value size used so each value ends up in its own memtable, which was the original intention (note: the test has been broken in the sense that the test code didn't consider that memtable sizes below 64 KB get increased to 64 KB by `SanitizeOptions`, and has been passing only by accident). `DBTest.MemoryUsageWithMaxWriteBufferSizeToMaintain` relies on completely up-to-date values and thus was changed to use `ApproximateMemoryUsage` directly instead of going through the DB properties. Note: this should be safe in this case since there's only a single thread involved. Pull Request resolved: https://github.com/facebook/rocksdb/pull/8206 Test Plan: `make check` Reviewed By: riversand963 Differential Revision: D27866811 Pulled By: ltamasi fbshipit-source-id: 7bd754d0565e0a65f1f7f0e78ffc093beef79394
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.