Comparing Transaction Isolation Levels in MySQL and MariaDB Through Automated Hermitage Testing

Summary

This article discusses transaction isolation levels (Read Uncommitted, Read Committed, Repeatable Read, Serializable) in MySQL and MariaDB, comparing how they handle transaction anomalies like Read Skew and Lost Updates. The author notes that the SQL standard (including the 2023 version) remains ambiguous and allows inconsistent behavior. The article uses the concept of "Automating Hermitage" to explore differences in how MySQL and MariaDB implement transaction isolation, starting with an example of Dirty Writes.