How to Fix PostgreSQL Error: Checkpoint Request Failed

Checkpoint request failed errors occur when PostgreSQL cannot complete a checkpoint operation, which flushes dirty buffers to disk and creates a recovery point.

Impact

Can lead to long recovery times after crashes, performance degradation, and indicate serious I/O or resource problems.

Common Causes

1. Disk I/O overload
2. Insufficient disk space
3. Filesystem errors
4. Very large shared_buffers
5. Slow storage system

Troubleshooting and Resolution Steps

1. Check checkpoint statistics:

   SELECT * FROM pg_stat_bgwriter;
   

2. Adjust checkpoint settings:

   -- Increase checkpoint timeout
   ALTER SYSTEM SET checkpoint_timeout = '15min';
   
   -- Increase max_wal_size
   ALTER SYSTEM SET max_wal_size = '2GB';
   
   SELECT pg_reload_conf();
   

3. Monitor I/O:

   iostat -x 5
   

Additional Information

• Checkpoints are normal and necessary
• Tune checkpoint_completion_target (0.9 recommended)
• Monitor disk I/O capacity
• Consider faster storage for high-write workloads

Frequently Asked Questions

Q: How often should checkpoints occur?
A: Depends on workload. Default 5 minutes, but tune based on write volume and recovery time requirements.