Debugging Deadlocks in PostgreSQL
a year ago
- #Debugging
- #PostgreSQL
- #Deadlock
- Debugging deadlocks in PostgreSQL can be tricky due to limited error details.
- Deadlocks occur when transactions block each other by holding conflicting locks.
- INSERT statements take FOR KEY SHARE locks on referenced rows, which can conflict with FOR UPDATE locks.
- Changing SELECT ... FOR UPDATE to SELECT ... FOR NO KEY UPDATE can prevent deadlocks.
- Understanding the full transaction context is crucial for diagnosing deadlocks.
- Several debugging methods include application logging, query comments, and PostgreSQL logging settings.
- Increasing deadlock_timeout can help in capturing deadlocks for debugging.
- Using pg_stat_activity and client-side tools like lsof can help identify hanging sessions.
- Debugging often requires control over application code or access to detailed logs.
- For more details, refer to articles on row locks and deadlocks in PostgreSQL.