oracular (7) ALTER_SYSTEM.7.gz

NAME

       ALTER_SYSTEM - change a server configuration parameter

SYNOPSIS

       ALTER SYSTEM SET configuration_parameter { TO | = } { 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, or after the
       next server restart in the case of parameters that can only be changed at server start. A server
       configuration reload can be commanded by calling the SQL function pg_reload_conf(), running pg_ctl
       reload, or sending a SIGHUP signal to the main server process.

       Only superusers and users granted ALTER SYSTEM privilege on a parameter can change it using 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 20.

       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. Values that are neither
           numbers nor valid identifiers must be quoted.  DEFAULT can be written to specify removing the
           parameter and its value from postgresql.auto.conf.

           For some list-accepting parameters, quoted values will produce double-quoted output to preserve
           whitespace and commas; for others, double-quotes must be used inside single-quoted strings to get
           this effect.

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 20.1 for other ways to set the parameters.

EXAMPLES

       Set the wal_level:

           ALTER SYSTEM SET wal_level = replica;

       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)