Tatsuo Ishii <ishii@postgresql.org> writes:
> Does anybody know PostgreSQL LISTEN/NOTIFY is more reliable than
> previous versions? I vaguely recall that in the previous
> implementation, message sent by NOTIFY may not be reached to listner.
> Does PostgreSQL 9.0's new implementation guarantee that the message is
> received by the listener?
No more or less than the old one did.
The old design intentionally dropped duplicate notifications, and the
new one does too (though with a narrower definition of "duplicate").
Modulo that well-documented behavior, I know of no reason to describe
either the old or new code as unreliable.
regards, tom lane