NAME

       ALTER_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 ALSO

       SET(7), SHOW(7)

PostgreSQL 9.5.25                                     2021                                       ALTER SYSTEM(7)