Understanding Checkpoints and Wall in Postgres

Checkpoints are a crucial aspect of Postgres' recovery system, allowing for data consistency and the ability to survive unexpected restarts or failures. The process involves writing dirty buffers, which are changed but not yet saved on disk, to disk. Checkpoints ensure that the changes reflected in the wall are saved, reducing the recovery time required after a crash. It is important to tune checkpoints based on recovery time requirements and the volume of wall data generated. Avoiding frequent checkpoints can help minimize overhead, but too infrequent checkpoints can lead to longer recovery times. Additionally, enabling wall compression and considering factors such as full page writes can significantly impact checkpoint performance.