Andreas 'ads' Scherbaum wrote:
> It is possible, that some notifies, if following in a very short time
> frame, can get lost.
>
> In case we want to send extra text messages with NOTIFY, we should make
> sure, that no notify get lost.
Right. Currently, NOTIFY acts like Unix signals -- consecutive signals
can get "collapsed" into a single one, and the listening process is
responsible for ensuring that it gets the communication details from
elsewhere.
If the idea is to convert NOTIFY into a full-blown communication system,
then no collapsing can take place. This means the additional data
(which can be of unbounded size) must be stored elsewhere, probably on
disk.
So far (AFAIK), the only detailed design proposal came from Neil Conway,
which used SLRU for storage, but AFAIK he didn't take it much further.
--
Alvaro Herrera http://www.CommandPrompt.com/
PostgreSQL Replication, Consulting, Custom Development, 24x7 support