Summary:
This is a duplicate of https://github.com/facebook/rocksdb/issues/4948 by mzhaom to fix tests after rebase.
This change is a follow-up to https://github.com/facebook/rocksdb/issues/4927, which made this possible by allowing tombstone dropping/seqnum zeroing optimizations on the last key in the compaction. Now the `largest_seqno != 0` condition suffices to prevent snapshot release triggered compaction from entering an infinite loop.
The issues caused by the extraneous condition `level_and_file.second->num_deletions > 1` are:
- files could have `largest_seqno > 0` forever making it impossible to tell they cannot contain any covering keys
- it doesn't trigger compaction when there are many overwritten keys. Some MyRocks use case actually doesn't use Delete but instead calls Put with empty value to "delete" keys, so we'd like to be able to trigger compaction in this case too.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8357
Test Plan: - make check
Reviewed By: jay-zhuang
Differential Revision: D28855340
Pulled By: ajkr
fbshipit-source-id: a261b51eecafec492499e6d01e8e43112f801798
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Andrew Kryczka4 years agocommitted byFacebook GitHub Bot
* Added API comments clarifying safe usage of Disable/EnableManualCompaction and EventListener callbacks for compaction.
* Obsolete keys in the bottommost level that were preserved for a snapshot will now be cleaned upon snapshot release in all cases. This form of compaction (snapshot release triggered compaction) previously had an artificial limitation that multiple tombstones needed to be present.