Re: Dead lock after the migration from CentOS 7 to RHEL 9 - Mailing list pgsql-admin

The error message indicates a deadlock situation between two processes in your PostgreSQL database. A deadlock occurs when two or more processes are blocked indefinitely, each waiting for the other to release a lock.

Here's a breakdown of the error message:

- Process 2197043 is waiting for an AccessExclusiveLock on relation 10384355 (a table or index).
- Process 1889236 is holding the lock that process 2197043 is waiting for and is waiting for a RowExclusiveLock on relation 10168609 (another table or index).
- Process 2197043 is holding the lock that process 1889236 is waiting for, creating a deadlock.

To resolve this issue:

1. Check the server log for query details, as hinted in the error message. This will help you identify the queries causing the deadlock.
2. Analyze the queries and identify any potential causes, such as:
    - Long-running transactions
    - Lock contention between multiple processes
    - Poorly indexed tables
3. Consider the following solutions:
    - Optimize queries to reduce lock contention
    - Use more granular locking (e.g., RowShareLock instead of RowExclusiveLock)
    - Split long-running transactions into smaller ones
    - Reindex tables during a maintenance window to minimize lock contention
4. If the issue persists, consider increasing the deadlock_timeout parameter to allow PostgreSQL to detect and resolve deadlocks more efficiently.

Remember to exercise caution when making changes to your database configuration or queries, as they may impact performance or data integrity.