Wiki / Configuration Parameters

Method used for forcing WAL updates out to disk. If fsync is off then this setting is irrelevant, since WAL file updates will not be forced out at all. Possible values are: open_datasync (write WAL files with open() option O_DSYNC) fdatasync (call fdatasync() at each commit) fsync (call fsync() at each commit) fsync_writethrough (call fsync() at each commit, forcing write-through of any disk write cache) open_sync (write WAL files with open() option O_SYNC) Not all of these choices are available on all platforms. The default is the first method in the above list that is supported by the platform, except that fdatasync is the default on Linux and FreeBSD. The default is not necessarily ideal; it might be necessary to change this setting or other aspects of your system configuration in order to create a crash-safe configuration or achieve optimal performance. These aspects are discussed in Section 28.1. 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

fdatasync

category

Write-Ahead Log / Settings

context

sighup

documented

true

enumvals

fsync, fdatasync, open_sync, open_datasync

extra desc

Unknown

lang

en

max val

Unknown

metadata version

18

min val

Unknown

name

wal_sync_method

short desc

Selects the method used for forcing WAL updates to disk.

source

pg-settings-source-snapshot

unit

Unknown

vartype

enum