Re: [v9.3] Extra Daemons (Re: elegant and effective way for running jobs inside a database)

Excerpts from Kohei KaiGai's message of mar sep 11 12:46:34 -0300 2012:
> 2012/9/11 Alvaro Herrera <alvherre@2ndquadrant.com>:
> > Excerpts from Boszormenyi Zoltan's message of vie jun 29 09:11:23 -0400 2012:
> >
> >> We have some use cases for this patch, when can you post
> >> a new version? I would test and review it.
> >
> > What use cases do you have in mind?
> >
> I'm motivated with this feature to implement background calculation server
> to handle accesses to GPU device; to avoid limitation of number of processes
> that can use GPU device simultaneously.

Hmm, okay, so basically a worker would need a couple of LWLocks, a
shared memory area, and not much else?  Not a database connection.

> Probably, other folks have their use cases.
> For example, Zoltan introduced his use case in the upthread as follows:
> > - an SQL-driven scheduler, similar to pgAgent, it's generic enough,
> >   we might port it to this scheme and publish it

Hm, this would benefit from a direct backend connection to get the
schedule data (SPI interface I guess).

> > - a huge volume importer daemon, it was written for a very specific
> >   purpose and for a single client, we cannot publish it.

This one AFAIR requires more than one connection, so a direct data
connection is no good -- hence link libpq like walreceiver.

--
Álvaro Herrera                http://www.2ndQuadrant.com/
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