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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 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.
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.