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 spent on performing write operations during checkpointing, in milliseconds.
checkpoint_sync_time	double precision	Total time spent on performing sync operations during checkpointing, in milliseconds.
buffers_checkpoint	bigint	Number of buffers written during checkpointing.
buffers_clean	bigint	Number of buffers written by the BGWRITER thread.
maxwritten_clean	bigint	Number of times that the BGWRITER thread stops cleanup scanning because the number of pages refreshed in a single scan is too large.
buffers_backend	bigint	Number of buffers written directly by the backend.
buffers_backend_fsync	bigint	Number of times that the backend thread automatically executes fsync. Generally, fsync is called by the BGWRITER thread.
buffers_alloc	bigint	Number of buffers allocated.
stats_reset	timestamp with time zone	Time when the statistics of the current row were reset last time.