Re: Priorities for users or queries? - Mailing list pgsql-general

From Jim C. Nasby
Subject Re: Priorities for users or queries?
Date
Msg-id 20070223223826.GC11743@decibel.org
Whole thread Raw
In response to Re: Priorities for users or queries?  (Ron Mayer <rm_pg@cheapcomplexdevices.com>)
List pgsql-general
On Fri, Feb 23, 2007 at 12:07:56PM -0800, Ron Mayer wrote:
> Jim Nasby wrote:
> > The problem with using simple OS priority settings is you leave yourself
> > wide open to priority inversion.
>
> Which is why you either
>  (a) note that papers studying priority inversion on RDBMS's
>      find that it's a non issue on many RDBMS workloads; and
>      (except for real-time databases) you tend to still get
>      at least partial benefits even in the face of priority
>      inversions.
> or
>  (b) use a scheduler in your OS that supports priority
>      inheritance or other mechanisms to avoid priority
>      inversion problems.
>      If you want to use priority inheritance to avoid
>      the priority inversion settings it appears versions
>      of Linux, BSD, Windows, and Solaris at least give
>      you the ability to do so.
>
> > There is already work being done on a queuing system; take a look at the
> > bizgres archives.
>
> Which is cool; but not quite the same as priorities.
>
> It seems to me that Bizgres and/or PostgreSQL would not
> want to re-implement OS features like schedulers.

Actually, I believe part of the discussion also involved how to handle
long-running workloads that you don't want to monopolize the machine.
--
Jim C. Nasby, Database Architect                decibel@decibel.org
Give your computer some brain candy! www.distributed.net Team #1828

Windows: "Where do you want to go today?"
Linux: "Where do you want to go tomorrow?"
FreeBSD: "Are you guys coming, or what?"

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