From: Greg Smith <greg@2ndquadrant.com>
To: Kevin Grittner <Kevin.Grittner@wicourts.gov>
Cc: pgsql-performance@postgresql.org, Albe Laurenz <laurenz.albe@wien.gv.at>
Subject: Re: Linux I/O tuning: CFQ vs. deadline
Date: Mon, 08 Feb 2010 10:30:13 -0500
Message-ID: <4B702E05.1000708@2ndquadrant.com> (raw)
In-Reply-To: <4B6FD868020000250002F084@gw.wicourts.gov>
References: <4B6FDD26.9010106@2ndquadrant.com>
<D960CB61B694CF459DCFB4B0128514C203938157@exadv11.host.magwien.gv.at>
<4B6FD868020000250002F084@gw.wicourts.gov>
Kevin Grittner wrote:
> I'll keep this in mind as something to try if we have problem
> performance in line with what that page describes, though....
>
That's basically what I've been trying to make clear all along: people
should keep an open mind, watch what happens, and not make any
assumptions. There's no clear cut preference for one scheduler or the
other in all situations. I've seen CFQ do much better, you and Albe
report situations where the opposite is true. I was just happy to see
another report of someone running into the same sort of issue I've been
seeing, because I didn't have very much data to offer about why the
standard advice of "always use deadline for a database app" might not
apply to everyone.
--
Greg Smith 2ndQuadrant Baltimore, MD
PostgreSQL Training, Services and Support
greg@2ndQuadrant.com www.2ndQuadrant.com
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To: pgsql-performance@postgresql.org
Cc: greg@2ndquadrant.com, Kevin.Grittner@wicourts.gov, laurenz.albe@wien.gv.at
Subject: Re: Linux I/O tuning: CFQ vs. deadline
In-Reply-To: <4B702E05.1000708@2ndquadrant.com>
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