How to Fix Deadlock Detected in PostgreSQL

What Is a Deadlock?

A deadlock occurs when two transactions block each other by holding locks on resources the other needs.

Example

Transaction A locks row 1 and waits for row 2. Transaction B locks row 2 and waits for row 1.

How to Fix

• Keep transactions short
• Access tables in consistent order
• Use lower isolation levels if possible

Prevention

Design queries and transaction flow carefully to avoid circular locking.