Summary:
- Closes https://github.com/facebook/rocksdb/issues/6490
- Currently MERGEs are converted to PUTs at bottom or compaction has reached the beginning of the key, this can wrongly cover a PUT future base case.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7166
Test Plan:
- Automated: `make all check`
- Manual: With `allow_ingest_behind = true`, add Merge operations to a key then run compaction. Then run ingesting external files to make sure the base case is probably compacted with existing Merges.
Reviewed By: cheng-chang
Differential Revision: D23325425
Pulled By: ajkr
fbshipit-source-id: 3eb415eb7b381b5453e45245393566153b1abb68