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UNLISTEN

Name

UNLISTEN  --  stop listening for a notification

Synopsis

UNLISTEN { notifyname | * }
  

Inputs

notifyname

Name of previously registered notify condition.

*

All current listen registrations for this backend are cleared.

Outputs

UNLISTEN

Acknowledgment that statement has executed.

Description

UNLISTEN is used to remove an existing NOTIFY registration. UNLISTEN cancels any existing registration of the current PostgreSQL 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

notifyname need not be a valid class name but can be any string valid as a name up to 64 characters long.

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

Usage

To subscribe to an existing registration:

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

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

UNLISTEN virtual;
UNLISTEN
NOTIFY virtual;
NOTIFY
-- notice no NOTIFY event is received

Compatibility

SQL92

There is no UNLISTEN in SQL92.

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