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  5. PG_STAT_BGWRITER

PG_STAT_BGWRITER

PG_STAT_BGWRITER showing statistics about the background writer process's activity.

Table 1 PG_STAT_BGWRITER 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 amount of time that has been spent in the portion of checkpoint processing where files are written to disk, in milliseconds

checkpoint_sync_time

double precision

Total amount of time that has been spent in the portion of checkpoint processing where files are synchronized to disk, in milliseconds

buffers_checkpoint

bigint

Number of buffers written during checkpoints

buffers_clean

bigint

Number of buffers written by the background writer

maxwritten_clean

bigint

Number of times the background writer 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 handles those even when the backend does its own write)

buffers_alloc

bigint

Number of buffers allocated

stats_reset

timestamp with time zone

Time when these statistics were reset