hello look to orafce package http://www.pgsql.cz/index.php/Oracle_functionality_%28en%29 regards Pavel 2008/6/19 David <wizzardx@xxxxxxxxx>: > Hi list. > > One pattern I've used is for apps to communicate events to each other > through the database. > > ie: > > - App 1 sents a boolean value to True > - App 2 queries the field every 10s, sets the value to False, and does > something. > > Is this reasonable, or should apps avoid this pattern? > > I have seen the NOTIFY and LISTEN SQL statements. However: > > 1) App 2 might not be running at the time (eg: it's launched from > cron, or it was temporarily stopped), and the expectation is that App > 2 will run the special logic when it is started. > > 2) App 2 is usually single-threaded, and needs to do other things in > it's main thread besides wait for a DB notification. > > I also know of RPC, but haven't used it before, and don't see a need > if you can use the above pattern. > > I would use RPC (or unix signals if on the same host) if App 2 needed > to respond quickly, and I didn't want to hammer the DB & network with > constant polling. > > Any comments? > > David. > > -- > Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-general >
