What problem does it solve? Standard SQL knowledge of SET TRANSACTION leads to errors in MariaDB: agents assume READ COMMITTED is the default, issue SET TRANSACTION mid-transaction, treat bare statements as session-sticky, and miss the ER_CHECKREAD (1020) error raised by innodb_snapshot_isolation under REPEATABLE READ. ## Core Features & Use Cases - Scope Rule Reference: Explains the GLOBAL / SESSION / next-transaction-only behavior of SET TRANSACTION, including why a bare statement fails with ERROR 1568 once a transaction is active. - Isolation Level Guidance: Covers MariaDB's REPEATABLE READ default, the deprecated tx_isolation variable versus transaction_isolation, and per-level locking semantics. - Snapshot Isolation Handling: Documents innodb_snapshot_isolation (ON by default since 11.6.2), which raises ER_CHECKREAD/1020 and rolls back the whole transaction on write-write conflicts, requiring retry logic that catches 1020 alongside deadlock 1213. - Use Case: When generating application retry logic for MariaDB transactions, use this Skill to ensure the code catches both error 1213 and error 1020 and retries the entire transaction rather than a single statement. ## Quick Start Ask the AI to write or review a MariaDB SET TRANSACTION statement or transaction retry logic and have it apply the correct scope rules and snapshot-isolation error handling.
