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This article investigates a deadlock that occurs when using INSERT … ON DUPLICATE KEY UPDATE in a multi‑threaded MySQL 8.0 environment, reproduces the issue, examines InnoDB lock logs, walks through the relevant source‑code call chain, and demonstrates how gap locks cause the deadlock.
This article explains the types of InnoDB row‑level locks—record lock, gap lock, and next‑key lock—describes how MySQL determines lock ranges based on indexing, outlines the two fundamental locking principles with associated optimizations, and provides concrete examples for primary‑key and ordinary indexes.
This article investigates how the MyBatis‑Plus saveOrUpdate method can trigger gap‑lock deadlocks in MySQL, explains the underlying concepts of deadlocks and gap locks, reproduces the issue with concrete SQL scripts, and proposes both risky and recommended mitigation strategies.
This article explains MySQL row‑level locking by analyzing three transactions—A, B, and C—to show why an UPDATE on a primary‑key column can block while an UPDATE on a non‑indexed column proceeds without waiting.
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 analyzes a MySQL InnoDB lock wait timeout error, explains how gap locks cause blocked inserts and phantom reads under repeatable‑read isolation, and offers optimization strategies such as primary‑key deletions, while concluding with a recruitment invitation for the Zero technology team.
This article examines MySQL's INSERT locking behavior, explains why phantom reads do not occur under REPEATABLE READ isolation, and walks through compiling the MySQL source, debugging lock acquisition, and the role of insert‑intention and gap locks using detailed code examples and execution traces.
This article investigates a MySQL InnoDB deadlock observed during a holiday period, explains how gap locks and next‑key locks on a composite index cause mutual waiting, reproduces the issue with large test data, and offers practical guidelines to avoid similar deadlocks in production environments.
This article explains how InnoDB implements row locks, gap locks, and next‑key locks to prevent phantom reads, describes how the lock ranges are determined, and demonstrates their effects through multiple transaction scenarios with detailed SQL code examples.
This article provides a detailed overview of MySQL's locking mechanisms—including table, row, gap, and deadlock handling—across MyISAM and InnoDB storage engines, with practical code examples, performance considerations, and solutions for high‑concurrency scenarios.
This article explains the differences between MySQL table locks and row locks, describes how MyISAM and InnoDB handle locking, provides explicit lock syntax with examples, discusses gap locks, and offers practical recommendations for avoiding lock contention in concurrent applications.
This article examines MySQL's insert locking behavior, including unique‑key checks, S Next‑Key locks, insert‑intention locks, gap locks, and the resulting deadlock scenarios, and provides practical recommendations for avoiding such lock conflicts in production environments.
This article examines why concurrent upsert operations in a high‑throughput MySQL service can cause deadlocks due to GAP locks and phantom reads, explains the underlying InnoDB locking mechanisms, and offers practical solutions such as adjusting isolation levels or redesigning data sharding logic.