Re: Prioritizing queries

Some OS's (like FreeBSD) will take process priority into account for
disk I/O. I frankly don't understand why linux doesn't.

On Tue, Sep 21, 2004 at 02:04:26PM -0700, Steve Atkins wrote:
> On Tue, Sep 21, 2004 at 04:24:21PM -0400, Christopher Petrilli wrote:
> > Has anyone investigated having either high, or low urgency queries? A
> > system I'm working on has a constant inflow of data, which has some
> > queries gainst it which might require long sequential scans. I'm not
> > that worried about how long those queries take, just that they don't
> > interfere with other insertions.
> >
> > This is a bit DSSish, I guess, but I would think it could be managed
> > by nicing processes?
>
> I'd like this feature on some boxes that are being pushed a bit too
> close to the limit for comfort.
>
> I've played around with some of the crude ways of doing it. Disk I/O
> tends to be the resource that's limited, and process niceness won't
> affect that. You'd need to do something like explicitly do a nanosleep
> for every X blocks read in by a query or somesuch. Perhaps a
> generalization of the vacuum-sleep hack.
>
> Cheers,
>   Steve
>
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--
Jim C. Nasby, Database Consultant               decibel@decibel.org
Give your computer some brain candy! www.distributed.net Team #1828

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