Open-source tool Monastery automates the Hermitage test suite to compare transaction isolation anomalies across MySQL and MariaDB at each isolation level.
Key Takeaways
SQL standard isolation levels (Read Uncommitted through Serializable) are defined via anomalies like Dirty Reads and Lost Updates, but the standard itself is ambiguous even in the 2023 revision.
No major database allows Dirty Writes in practice, but the SQL spec technically permits them – Monastery tests whether databases enforce this correctly.
The bowling-alley shoe thought experiment (from Lorin Hochstein) is formalized into executable SQL scripts to probe isolation guarantees across engines.
Monastery runs these scripts against MySQL and MariaDB at multiple isolation levels, exposing where each engine’s behavior diverges from the standard or from each other.
Author Phil Eaton has direct background in Postgres internals (EnterpriseDB), TigerBeetle, and Oracle – the tooling targets practitioners who need empirical isolation data, not just docs.
