SET(7)                                                    SQL Commands                                                    SET(7)



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 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_func-
       tion(7)]), the effects of the SET LOCAL command disappear at function exit; that is, the value in effect when  the  func-
       tion  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.

              Note: In PostgreSQL versions 8.0 through 8.2, the effects of a SET LOCAL would be canceled by releasing an earlier
              savepoint,  or  by  successful exit from a PL/pgSQL exception block. This behavior has been changed because it was
              deemed unintuitive.


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 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 cur-
              rent session).

       Besides the configuration parameters documented in 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; if this has not
                     been explicitly set anywhere, it will be the zone that the server's operating system defaults to).

       See in the documentation for more information about time zones.

NOTES
       The function set_config provides equivalent functionality; see 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 Post-
       greSQL allows more flexible time-zone specifications. All other SET features are PostgreSQL extensions.

SEE ALSO
       RESET [reset(7)], SHOW [show(7)]



SQL - Language Statements                                  2011-09-22                                                     SET(7)