UNLISTEN

PostgreSQL
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UNLISTEN

Name

UNLISTEN — Stop listening for notification

UNLISTEN { notifyname | * }

Inputs

notifyname: Name of previously registered notify condition.
*: All current listen registrations for this backend are cleared.

Outputs

UNLISTEN: Acknowledgement that statement has executed.

Description

UNLISTEN is used to remove an existing NOTIFY registration. UNLISTEN cancels any existing registration of the current Postgres session as a listener on the notify condition notifyname. The special condition wildcard "*" cancels all listener registrations for the current session.

NOTIFY contains a more extensive discussion of the use of LISTEN and NOTIFY.

Notes

classname needs not to be a valid class name but can be any string valid as a name up to 32 characters long.

The backend does not complain if you UNLISTEN something you were not listening for. Each backend will automatically execute UNLISTEN * when exiting.

A restriction in some previous releases of Postgres that a classname which does not correspond to an actual table must be enclosed in double-quotes is no longer present.

Usage

To subscribe to an existing registration:

postgres=> LISTEN virtual;
LISTEN
postgres=> NOTIFY virtual;
NOTIFY
Asynchronous NOTIFY 'virtual' from backend with pid '8448' received

Once UNLISTEN has been executed, further NOTIFY commands will be ignored:

postgres=> UNLISTEN virtual;
UNLISTEN
postgres=> NOTIFY virtual;
NOTIFY
-- notice no NOTIFY event is received

Compatibility

SQL92

There is no UNLISTEN in SQL92.

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