MySQL and MariaDB Deadlocks shows deadlock and transaction conflict information for a monitored server.
Workflow
- Open Deadlocks.
- Review recent events.
- Identify involved sessions, queries, and objects where available.
- Compare with Activity, InnoDB, and Queries.
Live And Historical Deadlock Data
The MySQL and MariaDB Deadlocks page includes the Mini DBA Time Range selector. Use Live for the current deadlock view, or switch to Last Hour, Last 12 Hours, Last Day, Last Week, or Custom to review historical deadlock events. Mini DBA loads and caches the selected historical deadlock dataset for the current console session and server context, so reviewing event detail alongside activity and InnoDB evidence stays quick after the range has loaded. Use Back to Live to resume live updates, then choose another historical range when you need a different incident window.
How To Investigate MySQL And MariaDB Deadlocks
Deadlocks happen when transactions wait on each other in a cycle and the database engine chooses one transaction to roll back. In MySQL and MariaDB systems using InnoDB, recurring deadlocks often point to application transaction design, inconsistent update order, missing indexes on lookup predicates, or batch jobs competing with online workload.
Start by identifying whether the same tables, indexes, statements, or application workflows appear repeatedly. If deadlocks occur during a scheduled task, compare event times with maintenance, imports, reports, or deployments. Then use InnoDB for transaction context and Queries for the SQL statements involved.
Deadlock handling should include application retry logic for safe operations. However, retries should not be the only fix when the same pattern appears often. Reducing transaction length, updating tables in a consistent order, and adding appropriate indexes can reduce the chance of future conflicts.
MySQL And MariaDB Deadlock FAQ
Are deadlocks normal?
Occasional deadlocks can happen on busy transactional systems. Frequent or user-visible deadlocks should be investigated.
Can a timeout setting prevent deadlocks?
No. Timeout settings affect how long sessions wait, but they do not remove the circular dependency that creates a deadlock.
What information helps developers?
Provide the time, table, index, statements, transaction flow, and whether the application retried successfully.
Next Steps After A Deadlock
Turn deadlock evidence into a transaction sequence that developers and DBAs can review. Capture the time, statements, tables, indexes, users, and application workflow. Then check whether the same tables are updated in different orders or whether missing indexes are causing more rows to be locked than expected. Repeating deadlocks usually need a design fix.