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Sep 7, 2026 · Databases

InnoDB Checkpoint Internals: Sync vs Fuzzy, Crash Recovery Detection, and Four Failure Scenarios

This article explains InnoDB's checkpoint mechanism, contrasting synchronous and fuzzy checkpoints, detailing the pre-MySQL 8.0 fuzzy checkpoint implementation using flush lists and page cleaners, and describing two principles for detecting abnormal shutdowns plus four post-restart crash scenarios with their recovery requirements.