Hi, Currently one can know the kind of on-going/last checkpoint (shutdown, end-of-recovery, immediate, force etc.) only via server logs that to when log_checkpoints GUC is on. At times, the users/service layer components would want to know the kind of checkpoint (along with other checkpoint related info) to take some actions and it will be a bit difficult to search through the server logs. The checkpoint info can be obtained from the control file (either by pg_control_checkpoint() or by pg_controldata tool) whereas checkpoint kind isn't available there.
How about we add an extra string field to the control file alongside the other checkpoint info it already has? This way, the existing pg_control_checkpoint() or pg_controldata tool can easily be enhanced to show the checkpoint kind as well. One concern is that we don't want to increase the size of pg_controldata by more than the typical block size (of 8K) to avoid any torn-writes. With this change, we might add at max the strings specified at [1]. Adding it to the control file has an advantage of preserving the last checkpoint kind which might be useful. Thoughts? [1] for checkpoint: "checkpoint shutdown end-of-recovery immediate force wait wal time flush-all" for restartpoint: "restartpoint shutdown end-of-recovery immediate force wait wal time flush-all" Regards, Bharath Rupireddy.
