Module deadlock 

Deadlock and serialization failure detection utilities.

“Always be prepared to re-issue a transaction if it fails due to deadlock. Deadlocks are not dangerous. Just try again.” — MySQL 8.0 Reference Manual, InnoDB Deadlocks

InnoDB detects deadlocks instantly and rolls back one transaction (the victim). SQLSTATE 40001 signals a serialization failure that is always safe to retry. This module provides detection helpers for use by callers that manage their own transaction lifecycle (e.g., the outbox sequencer, hierarchy mutations).

Functions

is_deadlock

Returns true if the error contains SQLSTATE 40001.

is_serialization_failure

Returns true if the error is a retryable serialization failure.