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Peter Dillinger
87c554b492
Summary: last_compacted_manifest_file_size_ drives TuneMaxManifestFileSize() to compute the manifest rotation threshold, but it started at 0 on every DB::Open and was only populated after the first manifest rotation. This is really only a problem with reuse_manifest_on_open, because no fresh manifest is created on open. Add a new forward-compatible (safe-to-ignore) MANIFEST tag kLastCompactedManifestFileSize that records the approximate compacted manifest size at the end of WriteCurrentStateToManifest. During recovery, the value is loaded and used to immediately tune the rotation threshold. The record includes a rough estimate of its own overhead (~15 bytes) and must be the last record written by WriteCurrentStateToManifest for accurate estimation. Pull Request resolved: https://github.com/facebook/rocksdb/pull/14725 Test Plan: Extended AutoTuneManifestSize in db_etc3_test to close and reopen with reuse_manifest_on_open after establishing a known auto-tuning state. Verifies that the manifest file number is preserved (no spurious rotation) and that subsequent CF additions don't trigger rotation -- proving the persisted compacted size keeps the tuned threshold correct. Verified the test fails when the recovery loading is disabled. Relax a fragile Java test that was dependent on the exact size of the manifest file. SHORT_TEST=1 ./tools/check_format_compatible.sh Reviewed By: anand1976 Differential Revision: D104464522 Pulled By: pdillinger fbshipit-source-id: 4f5d22d2e149bd40a523ee11780e5e3344803c19
451 B
451 B
Add reuse_manifest_on_open DBOption (default false). When enabled, DB::Open reuses the existing MANIFEST file for append instead of creating a fresh one, avoiding the cost of serializing the entire database state into a new MANIFEST on the first post-open write. To prevent this feature from interfering with manifest file size auto-tuning, an extra forward-compatible field is now always added to the MANIFEST (to track the last "compacted" size).