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

2012-09-11 17:58 keltezéssel, Alvaro Herrera írta:
> Excerpts from Kohei KaiGai's message of mar sep 11 12:46:34 -0300 2012:
>> 2012/9/11 Alvaro Herrera <alvherre(at)2ndquadrant(dot)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).

Indeed. And the advantage is that the scheduler's lifetime is exactly
the server's lifetime so there is no need to try reconnecting as soon
as the server goes away and wait until it comes back.

>>> - 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.

Yes.

Best regards,
Zoltán Böszörményi

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Zoltán Böszörményi
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