Mastering PostgreSQL 9.6

Tracking the background worker

In this section, it is time to take a look at the background writer statistics. As you might know, database connections will in many cases not write blocks to disks directly. Instead, data is written by the background writer process or by the checkpointer.

To see how data is written, the pg_stat_bgwriter view can be inspected:

test=# \d pg_stat_bgwriter                View "pg_catalog.pg_stat_bgwriter"         Column         |           Type           | Modifiers  -----------------------+--------------------------+-----------  checkpoints_timed     | bigint                   |   checkpoints_req       | bigint                   |   checkpoint_write_time | double precision         |   checkpoint_sync_time  | double precision         |   buffers_checkpoint    | bigint                   |   buffers_clean         | bigint                   |   maxwritten_clean      | bigint                   |   buffers_backend ...