Wiki / Configuration Parameters

Specifies how often the WAL writer flushes WAL, in time terms. After flushing WAL the writer sleeps for the length of time given by wal_writer_delay, unless woken up sooner by an asynchronously committing transaction. 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 this value is specified without units, it is taken as milliseconds. The default value is 200 milliseconds (200ms). Note that on some systems, the effective resolution of sleep delays is 10 milliseconds; setting wal_writer_delay to a value that is not a multiple of 10 might have the same results as setting it to the next higher multiple of 10. 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

200

category

Write-Ahead Log / Settings

context

sighup

documented

true

enumvals

Unknown

extra desc

Unknown

lang

en

max val

10000

metadata version

18

min val

1

name

wal_writer_delay

short desc

Time between WAL flushes performed in the WAL writer.

source

pg-settings-source-snapshot

unit

ms

vartype

integer