
SET — change a run-time parameter

## Synopsis

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

## Description

The `SET` command changes run-time configuration parameters. Many of the run-time parameters listed in [Chapter 19](https://www.postgresql.org/docs/current/runtime-config.html "Chapter 19. Server Configuration") can be changed on-the-fly with `SET`. (Some parameters can only be changed by superusers and users who have been granted `SET` privilege on that parameter. There are also parameters that 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](https://www.postgresql.org/docs/current/sql-createfunction.html "CREATE FUNCTION")), 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 `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. Issuing this outside of a transaction block emits a warning and otherwise has no effect.

_`configuration_parameter`_

Name of a settable run-time parameter. Available parameters are documented in [Chapter 19](https://www.postgresql.org/docs/current/runtime-config.html "Chapter 19. Server Configuration") 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 19](https://www.postgresql.org/docs/current/runtime-config.html "Chapter 19. Server Configuration"), 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 inclusive.

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:

`'America/Los_Angeles'`

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`).

Timezone settings given as numbers or intervals are internally translated to POSIX timezone syntax. For example, after `SET TIME ZONE -7`, `SHOW TIME ZONE` would report `<-07>+07`.

Time zone abbreviations are not supported by `SET`; see [Section 8.5.3](https://www.postgresql.org/docs/current/datatype-datetime.html#DATATYPE-TIMEZONES "8.5.3. Time Zones") for more information about time zones.

## Notes

The function `set_config` provides equivalent functionality; see [Section 9.28.1](https://www.postgresql.org/docs/current/functions-admin.html#FUNCTIONS-ADMIN-SET "9.28.1. Configuration Settings Functions"). Also, it is possible to UPDATE the [`pg_settings`](https://www.postgresql.org/docs/current/view-pg-settings.html "53.25. 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 'America/Los\_Angeles';

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 extensions.
