PostgresDB 40001: Transaction rollback

What is PostgresDB 40001: Transaction rollback

When encountering the error 40001: Transaction rollback in Postgres due to serialization failure, follow these immediate actions:

Retry the Transaction:Initially, simply retry the transaction that failed. Serialization errors often resolve on a subsequent attempt.Check Application Logs:Review your application logs closely around the time of the error for any anomalies or additional errors that might indicate what caused the transaction conflict.Investigate Locks and Conflicts:Run the following query to identify locking issues which could lead to serialization failures:SELECT blocked_locks.pid AS blocked_pid, blocked_activity.usename AS blocked_user, blocking_locks.pid AS blocking_pid, blocking_activity.usename AS blocking_user, blocked_activity.query AS blocked_statement, blocking_activity.query AS current_statement_in_blocking_processFROM pg_catalog.pg_locks blocked_locksJOIN pg_catalog.pg_stat_activity blocked_activity ON blocked_activity.pid = blocked_locks.pidJOIN pg_catalog.pg_locks blocking_locks ON blocking_locks.locktype = blocked_locks.locktype AND blocking_locks.DATABASE IS NOT DISTINCT FROM blocked_locks.DATABASE AND blocking_locks.relation IS NOT DISTINCT FROM blocked_locks.relation AND blocking_locks.page IS NOT DISTINCT FROM blocked_locks.page AND blocking_locks.tuple IS NOT DISTINCT FROM blocked_locks.tuple AND blocking_locks.virtualxid IS NOT DISTINCT FROM blocked_locks.virtualxid AND blocking_locks.transactionid IS NOT DISTINCT FROM blocked_locks.transactionid AND blocking_locks.classid IS NOT DISTINCT FROM blocked_locks.classid AND blocking_locks.objid IS NOT DISTINCT FROM blocked_locks.objid AND blocking_locks.objsubid IS NOT DISTINCT FROM blocked_locks.objsubid AND blocking_locks.pid != blocked_locks.pidJOIN pg_catalog.pg_stat_activity blocking_activity ON blocking_activity.pid = blocking_locks.pidWHERE NOT blocked_locks.GRANTED;This query helps identify transactions that are blocking others, potentially leading to the serialization error.Review Deadlocks:Check for deadlocks by looking into the PostgreSQL logs for entries tagged with deadlock detected. PostgreSQL automatically logs this information when it detects and resolves deadlocks.Analyze Transaction Isolation Levels:If the error persists and is caused by transactions interfering with each other, consider adjusting the transaction isolation level as a temporary measure. Use the following command to set the session-level isolation to a lower level and see if it mitigates the issue:SET TRANSACTION ISOLATION LEVEL READ COMMITTED;Be cautious with changes to isolation levels as they can affect data consistency. This is intended as a temporary measure to diagnose the serialization failure.Monitor Database Performance Metrics:Check the database performance metrics, especially around locks, CPU usage, and I/O operations. High contention or resource usage can exacerbate serialization failures.

Remember, these actions are for immediate response to the issue. Investigating the root cause thoroughly might require deeper analysis based on the outcomes of these steps.