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This article examines how InnoDB acquires various row, gap, and next‑key locks during INSERT … ON DUPLICATE KEY UPDATE statements under REPEATABLE‑READ and READ‑COMMITTED isolation levels, illustrating the lock behavior with detailed SQL examples and performance‑schema queries.
This article examines how InnoDB acquires row‑level locks during INSERT … ON DUPLICATE KEY operations under REPEATABLE‑READ and READ‑COMMITTED isolation levels, explains the lock types on primary and unique indexes, and shows the rollback and lock‑conversion process with concrete SQL examples.
This article demonstrates how InnoDB acquires and releases row‑level locks for a sample table under REPEATABLE‑READ and READ‑COMMITTED isolation levels, showing the SQL statements used, the lock types observed in the performance_schema, and the reasons behind the observed locking patterns.
This article demonstrates how InnoDB handles row, next‑key, and gap locks for a SELECT … FOR SHARE query under REPEATABLE‑READ and READ‑COMMITTED isolation levels, showing the preparation steps, SQL examples, lock inspection queries, and a concise summary of the differences.
This article demonstrates how InnoDB acquires different types of row and gap locks under REPEATABLE-READ and READ-COMMITTED isolation levels by creating a test table, inserting data, setting transaction isolation, executing SELECT ... FOR SHARE statements, and inspecting lock information from performance_schema.
This tutorial demonstrates, using MySQL 8.0.32 InnoDB source code, how REPEATABLE-READ and READ-COMMITTED isolation levels affect the locking behavior of SELECT ... FOR SHARE statements on primary‑key rows, including preparation, execution, and detailed lock analysis.
This article examines how MySQL 8.0.32 InnoDB handles locking when inserting a row that violates a unique index under the READ‑COMMITTED isolation level, detailing the preparation steps, observed lock types, the underlying mechanism, and the final cleanup actions.
This article investigates why BenchmarkSQL stalls during MySQL performance testing, tracing the issue to REPEATABLE‑READ isolation causing a dead‑loop in delete‑select transactions, and demonstrates how switching to READ‑COMMITTED resolves the problem through detailed code inspection and experimental verification.
This article explains MySQL's four transaction isolation levels—READ UNCOMMITTED, READ COMMITTED, REPEATABLE READ, and SERIALIZABLE—by creating a simple table, inserting test data, and running step‑by‑step SQL scripts that illustrate the behavior of each level, including phenomena such as dirty reads, non‑repeatable reads, phantom reads, and locking.
This article investigates why S‑type GAP locks appear in deadlocks under the READ COMMITTED isolation level in MySQL InnoDB, detailing the transaction workflow, lock acquisition during INSERT operations, lock inheritance after rollbacks, and reproducing the deadlock scenario with code examples and diagrams.
This article explains why MySQL chooses Repeatable Read as its default transaction isolation level, contrasting it with Oracle’s default Read Committed, and discusses how binlog formats, GAP locks, and historical bugs influence this design decision.