Why MySQL Returns Old Values After Update: Inside InnoDB Snapshot Reads

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.

InnoDBSnapshot ReadUpdate Anomaly

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Why MySQL Returns Old Values After Update: Inside InnoDB Snapshot Reads

Architecture & Thinking

Nov 22, 2023 · Databases

How Do RC and RR Isolation Levels Differ in MySQL Snapshot Reads?

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.

Isolation LevelsSnapshot Readmysql

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How Do RC and RR Isolation Levels Differ in MySQL Snapshot Reads?