SET — change a run-time parameter
SET [ SESSION | LOCAL ]configuration_parameter
{ TO | = } {value
| 'value
' | DEFAULT } SET [ SESSION | LOCAL ] TIME ZONE {timezone
| LOCAL | DEFAULT }
The SET
command changes run-time configuration
parameters. Many of the run-time parameters listed in
Chapter 17, Server Configuration 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.
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, Server Configuration 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 Chapter 17, Server Configuration, there are a few that can only be
adjusted using the SET
command or that have a
special syntax:
NAMES
SET NAMES
is an alias for
value
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
is an alias
for value
SET timezone TO
. The
syntax value
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 (the one that the server's operating system defaults to).
See Section 8.5.3, “Time Zones” for more information about time zones.
The function set_config
provides equivalent
functionality. See Section 9.20, “System Administration Functions”.
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';