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This article explains MySQL’s locking mechanisms, categorizing locks by performance, operation type, data granularity, and finer‑grained levels such as gap and next‑key locks, and offers guidance on selecting the appropriate lock strategy for reliable concurrent database operations.
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This article explains the concepts, usage scenarios, and differences of various database locks—including shared (S) lock, exclusive (X) lock, mutex, pessimistic and optimistic locks—as well as row‑level, table‑level, and page‑level locks, and it discusses common concurrency problems such as lost updates, non‑repeatable reads, dirty reads, and deadlocks.
This article explains the fundamentals of SQL Server locking, illustrates how row‑level locks can automatically escalate to table‑level locks during large batch operations, and provides practical techniques—such as batching deletes, adding appropriate indexes, and holding intent locks—to avoid lock escalation and improve concurrency.
This article explains the fundamentals of MySQL InnoDB transaction isolation levels, describes the four standard isolation grades, shows how InnoDB implements them in source code, and provides concrete case studies with SQL scripts to illustrate locking behavior and MVCC effects.
This article explains the purpose and classification of database locks, demonstrates how to manually apply and inspect table and row locks in MySQL, analyzes lock‑related status variables, and offers practical optimization strategies to improve concurrency and performance.
The guide explains MySQL/InnoDB deadlocks—how circular lock waits arise, the wait‑for‑graph detection that rolls back the transaction with fewer undo logs, the various lock modes and their behavior in UPDATE/INSERT/DELETE, and practical strategies such as proper indexing, consistent access order, and configuration tweaks to detect, handle, and prevent deadlocks.
This article explains MySQL's architecture, details the various metadata lock types, their acquisition and release processes, lock levels, and relationships, and then examines InnoDB's transaction isolation levels, lock types, lock levels, gap locks, and relevant source‑code structures.