SET
SQL - Language Statements
SET
change a run-time parameter
SET [ SESSION | LOCAL ] variable { 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
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 SET SESSION is issued
within a transaction that is later aborted, the effects of the
SET command disappear when the transaction is rolled
back. (This behavior represents a change from
PostgreSQL versions prior to 7.3, where
the effects of SET would not roll back after a later
error.) 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.
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.
variable
Name of a settable run-time parameter. Available parameters are
documented in and below.
value
New value of parameter. Values can be specified as string
constants, identifiers, numbers, or comma-separated lists of
these. DEFAULT can be used to specify
resetting the parameter to its default value.
Besides the configuration parameters documented in , there are a few that can only be
adjusted using the SET command or that have a
special 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 0 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.
'Portugal'
The time zone for Portugal.
'Europe/Rome'
The time zone for Italy.
7
The time zone 7 hours west from UTC (equivalent
to PDT). Negative 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 (the one that
your operating system defaults to).
See for more information
about time zones.
Diagnostics
SET
Message returned if successful.
ERROR: 'name' is not a valid option name
The parameter you tried to set does not exist.
ERROR: 'name': permission denied
You must be a superuser to alter certain settings.
ERROR: 'name' cannot be changed after server start
Some parameters are fixed once the server is started.
Notes
The function set_config provides equivalent
functionality. See .
Examples
Set the schema search path:
SET search_path TO my_schema, public;
Set the style of date to traditional
POSTGRES with European conventions:
SET datestyle TO postgres,european;
Set the time zone for Berkeley, California, using quotes to
preserve the uppercase spelling of the time zone name:
SET TIME ZONE 'PST8PDT';
SELECT current_timestamp AS today;
today
-------------------------------
2003-04-29 15:02:01.218622-07
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 extensions.
See Also