I'm seeing some applications where it appears that there would be value in introducing asynchronous messaging, ala "message queueing." <http://en.wikipedia.org/wiki/Message_queue>
The "granddaddy" of message queuing systems is IBM's MQ-Series, and I don't see particular value in replicating its functionality. On the other side, the "big names" these days are: a) The Java Messaging Service, which seems to implement *way* more options than I'm even vaguely interested in having (notably, lots that involve data stores or lack thereof that I do not care to use); b) AMPQ <http://en.wikipedia.org/wiki/Advanced_Message_Queuing_Protocol> which again is a big, complex, protocol-oriented thing that seems mighty big and complex; c) There are lesser names, like isectd <http://isectd.sf.net> and the (infamous?) Spread Toolkit which both implement memory-based messaging systems. There's a simple + free system called MQS that is implemented in Perl and uses XML-RPC; <http://www.foo.be/mqs/> that seems perhaps a little *too* primitive. FYI, here's its simple schema (filtered into PG): create table mqname ( name varchar (255) not null default '', id serial, priority integer not null default 10, primary key (id)); create table message ( id serial, timestamp timestamptz NOT NULL cid varchar(255), queue integer not null references mqname(id), body text not null, priority integer not null default 10, flag integer default 0, primary key(id) ); My bias would be to have something that can basically run as a thin set of stored procedures atop PostgreSQL :-). It would be trivial to extend that to support SOAP/XML-RPC, if desired. It would be nice to achieve 'higher availability' by having queues where you might replicate the contents (probably using the MQ system itself ;-)) to other servers. There tend to be varying semantics out there: - Some queues may represent "subscriptions" where a whole bunch of listeners want to get all the messages; - Sometimes you have the semantics where: - messages need to be delivered at least once - messages need to be delivered no more than once - messages need to be delivered exactly once Is there any existing work out there on this? Or should I maybe be looking at prototyping something? -- (format nil "[EMAIL PROTECTED]" "cbbrowne" "linuxfinances.info") http://linuxfinances.info/info/lsf.html Q: How many Newtons does it take to change a light bulb? A: Faux! There to eat lemons, axe gravy soup! ---------------------------(end of broadcast)--------------------------- TIP 6: explain analyze is your friend
