ALTER SYSTEM(7) PostgreSQL 9.5.0 Documentation ALTER SYSTEM(7)NAMEALTER_SYSTEM - change a server configuration parameter
SYNOPSIS
ALTER SYSTEM SET configuration_parameter { TO | = } { value | 'value' | DEFAULT }
ALTER SYSTEM RESET configuration_parameter
ALTER SYSTEM RESET ALL
DESCRIPTION
ALTER SYSTEM is used for changing server configuration parameters
across the entire database cluster. It can be more convenient than the
traditional method of manually editing the postgresql.conf file. ALTER
SYSTEM writes the given parameter setting to the postgresql.auto.conf
file, which is read in addition to postgresql.conf. Setting a parameter
to DEFAULT, or using the RESET variant, removes that configuration
entry from the postgresql.auto.conf file. Use RESET ALL to remove all
such configuration entries.
Values set with ALTER SYSTEM will be effective after the next server
configuration reload (SIGHUP or pg_ctl reload), or after the next
server restart in the case of parameters that can only be changed at
server start.
Only superusers can use ALTER SYSTEM. Also, since this command acts
directly on the file system and cannot be rolled back, it is not
allowed inside a transaction block or function.
PARAMETERS
configuration_parameter
Name of a settable configuration parameter. Available parameters
are documented in Chapter 18, Server Configuration, in the
documentation.
value
New value of the parameter. Values can be specified as string
constants, identifiers, numbers, or comma-separated lists of these,
as appropriate for the particular parameter. DEFAULT can be
written to specify removing the parameter and its value from
postgresql.auto.conf.
NOTES
This command can't be used to set data_directory, nor parameters that
are not allowed in postgresql.conf (e.g., preset options).
See Section 18.1, “Setting Parameters”, in the documentation for other
ways to set the parameters.
EXAMPLES
Set the wal_level:
ALTER SYSTEM SET wal_level = hot_standby;
Undo that, restoring whatever setting was effective in postgresql.conf:
ALTER SYSTEM RESET wal_level;
COMPATIBILITY
The ALTER SYSTEM statement is a PostgreSQL extension.
SEE ALSOSET(7), SHOW(7)PostgreSQL 9.5.0 2016 ALTER SYSTEM(7)
