BGWRITER_STAT

BGWRITER_STAT displays statistics about the background writer thread's activities, as described in Table 1.

**Table 1** BGWRITER_STAT columns
Name	Type	Description
checkpoints_timed	bigint	Number of scheduled checkpoints that have been performed.
checkpoints_req	bigint	Number of requested checkpoints that have been performed.
checkpoint_write_time	double precision	Total time that has been spent in the portion of checkpoint processing where files are written to disk (unit: ms).
checkpoint_sync_time	double precision	Total time that has been spent in the portion of checkpoint processing where files are synchronized to disk (unit: ms).
buffers_checkpoint	bigint	Number of buffers written during checkpoints.
buffers_clean	bigint	Number of buffers written by the background writer thread.
maxwritten_clean	bigint	Number of times the background writer thread stopped a cleaning scan because it had written too many buffers.
buffers_backend	bigint	Number of buffers written directly by a backend.
buffers_backend_fsync	bigint	Number of times a backend had to execute its own fsync call (normally the background writer thread handles those even when the backend does its own write).
buffers_alloc	bigint	Number of buffers allocated.
stats_reset	timestamp with time zone	Time at which these statistics were last reset.