A checkpoint is a point in the transaction log sequence at which all data files have been updated to reflect the information in the log. All data files will be flushed to a disk.
CHECKPOINT forces a transaction log checkpoint. By default, WALs periodically specify checkpoints in a transaction log. You may use gs_guc to specify run-time parameters checkpoint_segments and checkpoint_timeout to adjust the atomized checkpoint intervals. CHECKPOINT forces an immediate checkpoint when the related command is issued, without waiting for a regular checkpoint scheduled by the system.
Only a system administrator has the permission to call CHECKPOINT.
-- Set a checkpoint: CHECKPOINT;