SET SESSION

Synopsis

SET SESSION name = expression
SET SESSION catalog.name = expression

Description

Set a session property value or a catalog session property.

(session-properties-definition)=

Session properties

A session property is a {doc}configuration property </admin/properties> that can be temporarily modified by a user for the duration of the current connection session to the Trino cluster. Many configuration properties have a corresponding session property that accepts the same values as the config property.

There are two types of session properties:

• System session properties apply to the whole cluster. Most session properties are system session properties unless specified otherwise.
• Catalog session properties are connector-defined session properties that can be set on a per-catalog basis. These properties must be set separately for each catalog by including the catalog name as a prefix, such as catalogname.property_name.

Session properties are tied to the current session, so a user can have multiple connections to a cluster that each have different values for the same session properties. Once a session ends, either by disconnecting or creating a new session, any changes made to session properties during the previous session are lost.

Examples

The following example sets a system session property change maximum query run time:

SET SESSION query_max_run_time = '10m';

The following example sets the incremental_refresh_enabled catalog session property for a catalog using the named example:

SET SESSION example.incremental_refresh_enabled=false;

The related catalog configuration property iceberg.incremental-refresh-enabled defaults to true, and the session property allows you to override this setting in for specific catalog and the current session. The example.incremental_refresh_enabled catalog session property does not apply to any other catalog, even if another catalog also uses the Iceberg connector.

See also

{doc}reset-session, {doc}show-session