Summary:
currently for leveled compaction, the max output level of a call to `CompactRange()` is pre-computed before compacting each level. This max output level is the max level whose key range overlaps with the manual compaction key range. However, during manual compaction, files in the max output level may be compacted down further by some background compaction. When this background compaction is a trivial move, there is a race condition and the manual compaction may not be able to compact all keys in the specified key range. This PR updates `CompactRange()` to always compact to the bottommost level to make this race condition more unlikely (it can still happen, see more in comment here: 796f58f42a/db/db_impl/db_impl_compaction_flush.cc (L1180C29-L1184)).
This PR also changes the behavior of CompactRange() when `bottommost_level_compaction=kIfHaveCompactionFilter` (the default option). The old behavior is that, if a compaction filter is provided, CompactRange() always does an intra-level compaction at the final output level for all files in the manual compaction key range. The only exception when `first_overlapped_level = 0` and `max_overlapped_level = 0`. It’s awkward to maintain the same behavior after this PR since we do not compute max_overlapped_level anymore. So the new behavior is similar to kForceOptimized: always does intra-level compaction at the bottommost level, but not including new files generated during this manual compaction.
Several unit tests are updated to work with this new manual compaction behavior.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/11468
Test Plan: Add new unit tests `DBCompactionTest.ManualCompactionCompactAllKeysInRange*`
Reviewed By: ajkr
Differential Revision: D46079619
Pulled By: cbi42
fbshipit-source-id: 19d844ba4ec8dc1a0b8af5d2f36ff15820c6e76f
Changyu Bi
e95cc1217d