2b367fa8cc
Summary: In debug mode, we are seeing assertion failure as follows ``` db/compaction/compaction_iterator.cc:980: void rocksdb::CompactionIterator::PrepareOutput(): \ Assertion `ikey_.type != kTypeDeletion && ikey_.type != kTypeSingleDeletion' failed. ``` It is caused by releasing earliest snapshot during compaction between the execution of `NextFromInput()` and `PrepareOutput()`. In one case, as demonstrated in unit test `WritePreparedTransaction.ReleaseEarliestSnapshotDuringCompaction_WithSD2`, incorrect result may be returned by a following range scan if we disable assertion, as in opt compilation level: the SingleDelete marker's sequence number is zeroed out, but the preceding PUT is also outputted to the SST file after compaction. Due to the logic of DBIter, the PUT will not be skipped and will be returned by iterator in range scan. https://github.com/facebook/rocksdb/issues/8661 illustrates what happened. Fix by taking a more conservative approach: make compaction zero out sequence number only if key is in the earliest snapshot when the compaction starts. Another assertion failure is ``` Assertion `current_user_key_snapshot_ == last_snapshot' failed. ``` It's caused by releasing the snapshot between the PUT and SingleDelete during compaction. Pull Request resolved: https://github.com/facebook/rocksdb/pull/8608 Test Plan: make check Reviewed By: jay-zhuang Differential Revision: D30145645 Pulled By: riversand963 fbshipit-source-id: 699f58e66faf70732ad53810ccef43935d3bbe81
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.