Thx for the feedback I will take a look. Here some details. Basically what I'd like to achieve:
Internet <-> AppliA <-> PostgreSQL <-> AppliB 1) AppliA receives a request from the internet and calls a Pg/SQL function. 2) The Pg/SQL function informs AppliB that there is some work waiting (NOTIFY). 3) AppliB does the work and posts the result back to PostgreSQL. ... and now here's the problem -> The initial Pg/SQL function should give back the result computed by AppliB -> It has to wait somehow and get informed when the work from AppliB is done. Thx & cheers, Peter 2012/10/15 Craig Ringer <ring...@ringerc.id.au> > On 10/15/2012 08:54 PM, P. Broennimann wrote: > >> Hi there >> >> 1) Can a Pg/SQL function "listen" for a notification sent from an >> external instance? >> > > No, it's the other way around. A client can `LISTEN` for a `NOTIFY` sent > by another client, either directly or via a PL/PgSQL function. > > What you want is a NOTIFY callback or NOTIFY trigger, something that > invokes a function without any client action when a NOTIFY comes in. No > such feature exists. > > I would like my stored function to pause/wait and continue its execution >> once an external event (NOTIFY event) occurs. >> > > Use an advisory lock, they're ideal for that job: > > http://www.postgresql.org/**docs/current/static/explicit-** > locking.html#ADVISORY-LOCKS<http://www.postgresql.org/docs/current/static/explicit-locking.html#ADVISORY-LOCKS> > > 2) In Pg/SQL I can implement a loop (until something happens) to >> pause/wait. This costs CPU time -> Is there another solution? >> > > Depends on what you're waiting for. Details? > > Again, an advisory lock may be a candidate. > > -- > Craig Ringer >
