Re: Trigger that spawns forked process

On Tue, 2005-05-10 at 15:02, Christopher Murtagh wrote:
> On Tue, 2005-05-10 at 11:11 -0500, Jim C. Nasby wrote:
> > Well, LISTEN and NOTIFY are built into PostgreSQL
> > (http://www.postgresql.org/docs/8.0/interactive/sql-notify.html). If the
> > processes that you're trying to notify of the changes are connected to
> > the database then this might be the easiest way to do what you're
> > looking for. Setting up some form of replication, such as Slony, also
> > comes to mind. But it's impossible to really make a recommendation
> > without having a better idea of what you're doing.
> >
> > BTW, my understanding is that it's pretty easy to write a daemon in
> > perl, and there are examples of how to do this floating around.
>
> Yes, I saw the LISTEN/NOTIFY stuff, and it could be interesting. As to
> the replication, Slony won't do it for me, as it isn't the database I
> want to replicate. Here's a basic description:
>
> I have 4 cluster nodes all running the same content management software
> (home grown). When a change request comes in to one of them (update to
> an XML document), it submits the new XML doc to the database (which is
> the master repository of all content), then performs an XSLT. Upon the
> new change, I want the database to propagate the new result of the XSLT
> to the other nodes so that they can pre-cache it (to avoid page loading
> latency).

Seeing as how Slony replicates tables you choose to have it replicate,
it seems to me you could just have it replicate the post-xslt table and
it would do what you want.