My concern is how, after LISTENing in psql, I can tell it what to do when the NOTItFY is received.
As far as I am aware you cannot. The docs for psql, and its feature set, with respect to LISTEN, are minimal and basically say psql will print out notifications to stdout (this I'm forced to assume or read the code) and will poll for notifications whenever it sends a query to the server.
"Whenever a command is executed, psql also polls for asynchronous notification events generated by LISTEN and NOTIFY."
I suspect the feature request would be something like:
\set NOTIFY_PROGRAM './process-notify-request.bash' (or an equivalent meta-command)
And psql would invoke said program and pass the content of the notification payload to it via stdin.
Given what we allow for "\copy" I don't see any technical or conceptual problems with such a feature. Just needs someone to be its primary author.
David J.
