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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.