Type: enum
Default: origin
Context: superuser
Restart: false
Values: [origin, replica, local]

Controls firing of replication-related triggers and rules for the current session. Possible values are origin (the default), replica and local. Setting this parameter results in discarding any previously cached query plans. Only superusers and users with the appropriate SET privilege can change this setting.

The intended use of this setting is that logical replication systems set it to replica when they are applying replicated changes. The effect of that will be that triggers and rules (that have not been altered from their default configuration) will not fire on the replica. See the ALTER TABLE clauses ENABLE TRIGGER and ENABLE RULE for more information.

PostgreSQL treats the settings origin and local the same internally. Third-party replication systems may use these two values for their internal purposes, for example using local to designate a session whose changes should not be replicated.

Since foreign keys are implemented as triggers, setting this parameter to replica also disables all foreign key checks, which can leave data in an inconsistent state if improperly used.

Recommendations

Only gets changed for databases which are taking part in a replication chain. In that case, "origin" servers fire replication (and other) triggers, and "replica" do not. Part of the generic replication hooks which are used by Slony and Bucardo.

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