Summary:
ValidateSnapshot checks if another txn has committed a value to about-to-be-locked key since a particular snapshot. It applies an optimization of looking into only the memtable if snapshot seq is larger than the earliest seq in the memtables. With a long-running txn in WritePrepared, the prepared value might be flushed out to the disk and yet it commits after the snapshot, which breaks this optimization. The patch fixes that by disabling this optimization when the min_uncomitted seq at the time the snapshot was taken is lower than earliest seq in the memtables.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4961
Differential Revision: D14009947
Pulled By: maysamyabandeh
fbshipit-source-id: 1d11679950326f7c4094b433e6b821b729f08850
10d14693ac