From: Greg Smith <greg@2ndquadrant.com>
To: Samuel Gendler <sgendler@ideasculptor.com>
Cc: Joshua Tolley <eggyknap@gmail.com>
Cc: Craig Ringer <craig@postnewspapers.com.au>
Cc: mladen.gogala@vmsinfo.com, Neil Whelchel <neil.whelchel@gmail.com>
Cc: pgsql-performance@postgresql.org <pgsql-performance@postgresql.org>
Subject: Re: Slow count(*) again...
Date: Tue, 12 Oct 2010 02:39:32 -0400
Message-ID: <4CB402A4.9070109@2ndquadrant.com> (raw)
In-Reply-To: <AANLkTi=WE-CsGVC3j4CX9ddGGsRZ3Mmk6aJGKk4NT=g6@mail.gmail.com>
References: <201010091626.18636.neil.whelchel@gmail.com>
<4CB11CC7.8070300@vmsinfo.com>
<4CB167CA.9070109@postnewspapers.com.au>
<4CB1F46E.80205@vmsinfo.com>
<4CB2410C.6010603@postnewspapers.com.au>
<4cb25a0e.2a978e0a.7797.33d6@mx.google.com>
<4CB3C598.2010302@2ndquadrant.com>
<AANLkTi=WE-CsGVC3j4CX9ddGGsRZ3Mmk6aJGKk4NT=g6@mail.gmail.com>
Samuel Gendler wrote:
> I spent some time going through the various tuning docs on the wiki
> whie bringing some new hardware up and I can't remember seeing any
> discussion of tweaking read-ahead at all in the normal
> performance-tuning references. Do you have any documentation of the
> kinds of tweaking you have done and its effects on different types of
> workloads?
Much of my recent research has gone into the book you'll see plugged
below rather than the wiki. The basics of read-ahead tuning is that you
can see it increase bonnie++ sequential read results when you increase
it, to a point. Get to that point and stop and you should be in good shape.
--
Greg Smith, 2ndQuadrant US greg@2ndQuadrant.com Baltimore, MD
PostgreSQL Training, Services and Support www.2ndQuadrant.us
Author, "PostgreSQL 9.0 High Performance" Pre-ordering at:
https://www.packtpub.com/postgresql-9-0-high-performance/book
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Cc: greg@2ndquadrant.com, sgendler@ideasculptor.com, eggyknap@gmail.com, craig@postnewspapers.com.au, neil.whelchel@gmail.com
Subject: Re: Slow count(*) again...
In-Reply-To: <4CB402A4.9070109@2ndquadrant.com>
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