trusty (7) SET.7.gz

NAME

       SET - change a run-time parameter

SYNOPSIS

       SET [ SESSION | LOCAL ] configuration_parameter { TO | = } { value | 'value' | DEFAULT }
       SET [ SESSION | LOCAL ] TIME ZONE { timezone | LOCAL | DEFAULT }

DESCRIPTION

       The SET command changes run-time configuration parameters. Many of the run-time parameters listed in
       Chapter 17, Coordinator and Datanode Configuration, in the documentation can be changed on-the-fly with
       SET. (But some require superuser privileges to change, and others cannot be changed after server or
       session start.)  SET only affects the value used by the current session.

       If SET (or equivalently SET SESSION) is issued within a transaction that is later aborted, the effects of
       the SET command disappear when the transaction is rolled back. Once the surrounding transaction is
       committed, the effects will persist until the end of the session, unless overridden by another SET.

       The effects of SET LOCAL last only till the end of the current transaction, whether committed or not. A
       special case is SET followed by SET LOCAL within a single transaction: the SET LOCAL value will be seen
       until the end of the transaction, but afterwards (if the transaction is committed) the SET value will
       take effect.

       The effects of SET or SET LOCAL are also canceled by rolling back to a savepoint that is earlier than the
       command.

       If SET LOCAL is used within a function that has a SET option for the same variable (see CREATE FUNCTION
       (CREATE_FUNCTION(7))), the effects of the SET LOCAL command disappear at function exit; that is, the
       value in effect when the function was called is restored anyway. This allows SET LOCAL to be used for
       dynamic or repeated changes of a parameter within a function, while still having the convenience of using
       the SET option to save and restore the caller's value. However, a regular SET command overrides any
       surrounding function's SET option; its effects will persist unless rolled back.

PARAMETERS

       SESSION
           Specifies that the command takes effect for the current session. (This is the default if neither
           SESSION nor LOCAL appears.)

       LOCAL
           Specifies that the command takes effect for only the current transaction. After COMMIT or ROLLBACK,
           the session-level setting takes effect again. Note that SET LOCAL will appear to have no effect if it
           is executed outside a BEGIN block, since the transaction will end immediately.

       configuration_parameter
           Name of a settable run-time parameter. Available parameters are documented in Chapter 17, Coordinator
           and Datanode Configuration, in the documentation and below.

       value
           New value of 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 resetting the parameter to its default value (that is, whatever value it would have had if
           no SET had been executed in the current session).

       Besides the configuration parameters documented in Chapter 17, Coordinator and Datanode Configuration, in
       the documentation, there are a few that can only be adjusted using the SET command or that have a special
       syntax:

       SCHEMA
           SET SCHEMA 'value' is an alias for SET search_path TO value. Only one schema can be specified using
           this syntax.

       NAMES
           SET NAMES value is an alias for SET client_encoding TO value.

       SEED
           Sets the internal seed for the random number generator (the function random). Allowed values are
           floating-point numbers between -1 and 1, which are then multiplied by 231-1.

           The seed can also be set by invoking the function setseed:

               SELECT setseed(value);

       TIME ZONE
           SET TIME ZONE value is an alias for SET timezone TO value. The syntax SET TIME ZONE allows special
           syntax for the time zone specification. Here are examples of valid values:

           'PST8PDT'
               The time zone for Berkeley, California.

           'Europe/Rome'
               The time zone for Italy.

           -7
               The time zone 7 hours west from UTC (equivalent to PDT). Positive values are east from UTC.

           INTERVAL '-08:00' HOUR TO MINUTE
               The time zone 8 hours west from UTC (equivalent to PST).

           LOCAL, DEFAULT
               Set the time zone to your local time zone (that is, the server's default value of timezone).

           See Section 8.5.3, “Time Zones”, in the documentation for more information about time zones.

NOTES

       The function set_config provides equivalent functionality; see Section 9.26, “System Administration
       Functions”, in the documentation. Also, it is possible to UPDATE the pg_settings system view to perform
       the equivalent of SET.

EXAMPLES

       Set the schema search path:

           SET search_path TO my_schema, public;

       Set the style of date to traditional POSTGRES with “day before month” input convention:

           SET datestyle TO postgres, dmy;

       Set the time zone for Berkeley, California:

           SET TIME ZONE 'PST8PDT';

       Set the time zone for Italy:

           SET TIME ZONE 'Europe/Rome';

COMPATIBILITY

       SET TIME ZONE extends syntax defined in the SQL standard. The standard allows only numeric time zone
       offsets while Postgres-XC allows more flexible time-zone specifications. All other SET features are
       PostgreSQL extensions.

SEE ALSO

       RESET(7), SHOW(7)