doc: update bgwriter description
authorBruce Momjian <bruce@momjian.us>
Mon, 16 Nov 2020 18:13:43 +0000 (13:13 -0500)
committerBruce Momjian <bruce@momjian.us>
Mon, 16 Nov 2020 18:13:43 +0000 (13:13 -0500)
commita39de0c415fa6f0e215c97e4d587aaa6482174ca
tree8f923e4df21c1a8ef5b61aba8a572d4db2af4b51
parent4dccb5c59ff7f9c6cfd3ddfe7ab98b2d7a2b7e6f
doc:  update bgwriter description

This clarifies exactly what the bgwriter does, which should help with
tuning.

Reported-by: Chris Wilson
Discussion: https://postgr.es/m/160399562040.7809.7335281028960123489@wrigleys.postgresql.org

Backpatch-through: 9.5
doc/src/sgml/config.sgml