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 

Acknowledgment 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 need not 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:

 

        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.