This article explains how MySQL's MVCC uses version chains and ReadViews to enable lock-free snapshot reads, why isolation levels control ReadView creation timing (per-statement vs per-transaction), and why READ UNCOMMITTED and SERIALIZABLE bypass MVCC entirely, while writes still require row locks.
This article explains MySQL's MVCC mechanism in InnoDB, detailing how hidden fields, undo logs, and Read Views enable lock-free snapshot reads, the differences between RC and RR isolation levels, why MVCC prevents non-repeatable reads but not phantom reads, and common pitfalls like long transactions causing undo log bloat.
This article explains how MySQL's Repeatable Read isolation level prevents phantom reads by combining MVCC snapshot reads for consistent views and Next-Key Locks (record + gap locks) to block inserts during current reads like UPDATE, detailing the ReadView mechanism, version chains, and a concrete phantom read scenario.
This article explains MySQL InnoDB's MVCC mechanism, detailing how snapshot reads and current reads work, the hidden fields that drive versioning, the Read View rules for RC and RR isolation levels, and provides hands‑on SQL demos plus common pitfalls to avoid.
This article investigates a puzzling MySQL behavior where a row updated within a transaction sometimes returns its previous value, explains the role of InnoDB's snapshot reads and ReadView, reproduces the issue, and offers practical ways to prevent the “update disappearance” scenario.
This article explains the differences between Read Committed (RC) and Repeatable Read (RR) isolation levels in MySQL, detailing how snapshot reads work, why other levels avoid them, and illustrating their behavior with concrete transaction examples.
