Wiki / Configuration Parameters

Specifies how often the WAL writer flushes WAL, in volume terms. If the last flush happened less than wal_writer_delay ago and less than wal_writer_flush_after worth of WAL has been produced since, then WAL is only written to the operating system, not flushed to disk. If wal_writer_flush_after is set to 0 then WAL data is always flushed immediately. If this value is specified without units, it is taken as WAL blocks, that is XLOG_BLCKSZ bytes, typically 8kB. The default is 1MB. This parameter can only be set in the postgresql.conf file or on the server command line.

English manual coverage begins with PostgreSQL 7.4. Source history and runtime observations have their own recorded version boundaries.

boot val

128

category

Write-Ahead Log / Settings

context

sighup

documented

true

enumvals

Unknown

extra desc

Unknown

lang

en

max val

2147483647

metadata version

18

min val

0

name

wal_writer_flush_after

short desc

Amount of WAL written out by WAL writer that triggers a flush.

source

pg-settings-source-snapshot

unit

8kB

vartype

integer