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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 com-
       mand.

       If SET LOCAL is used within a function that has a SET option for the same variable (see CREATE  FUNCTION  [cre-
       ate_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.

              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 SES-
              SION 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-sep-
              arated 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 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  float-
              ing-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 syn-
              tax 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 PostgreSQL allows more flexible time-zone specifications. All other SET features  are  PostgreSQL  exten-
       sions.

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



SQL - Language Statements         2014-02-17                            SET(7)