Summary:
DBImpl extends the public GetSnapshot() with GetSnapshotForWriteConflictBoundary() method that takes snapshots specially for write-write conflict checking. Compaction treats such snapshots differently to avoid GCing a value written after that, so that the write conflict remains visible even after the compaction. The patch extends stress tests with such snapshots.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5897
Differential Revision: D17937476
Pulled By: maysamyabandeh
fbshipit-source-id: bd8b0c578827990302194f63ae0181e15752951d