rocksdb/unreleased_history/bug_fixes
Andrew Kryczka 7027265417 Fix `max_successive_merges` counting CPU overhead regression (#12546)
Summary:
In https://github.com/facebook/rocksdb/issues/12365 we made `max_successive_merges` non-strict by default. Before https://github.com/facebook/rocksdb/issues/12365, `CountSuccessiveMergeEntries()`'s scan was implicitly limited to `max_successive_merges` entries for a given key, because after that the merge operator would be invoked and the merge chain would be collapsed. After https://github.com/facebook/rocksdb/issues/12365, the merge chain will not be collapsed no matter how long it is when the chain's operands are not all in memory. Since `CountSuccessiveMergeEntries()` scanned the whole merge chain, https://github.com/facebook/rocksdb/issues/12365 had a side effect that it would scan more memtable entries. This PR introduces a limit so it won't scan more entries than it could before.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/12546

Reviewed By: jaykorean

Differential Revision: D56193693

Pulled By: ajkr

fbshipit-source-id: b070ba0703ef733e0ff230f89cd5cca5233b84da
2024-04-17 12:11:24 -07:00
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.gitkeep Better management of unreleased HISTORY (#11481) 2023-05-30 16:42:49 -07:00
max_successive_merges_regression.md Fix `max_successive_merges` counting CPU overhead regression (#12546) 2024-04-17 12:11:24 -07:00