From: Hannu Krosing <hannu@2ndquadrant.com>
To: Kevin Grittner <Kevin.Grittner@wicourts.gov>
Cc: Scott Marlowe <scott.marlowe@gmail.com>
Cc: Samuel Gendler <sgendler@ideasculptor.com>
Cc: pgsql-performance@postgresql.org, Tom Lane <tgl@sss.pgh.pa.us>
Subject: Re: Need help in performance tuning.
Date: Wed, 14 Jul 2010 17:54:51 +0300
Message-ID: <1279119291.3888.5.camel@hvost> (raw)
In-Reply-To: <4C3D7C2F020000250003353C@gw.wicourts.gov>
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<AANLkTin4Q4APRnbJ85FRasU7n8LuhKibKYcGnexsEbTt@mail.gmail.com>
<8760.1278650566@sss.pgh.pa.us>
<1278654529.7216.20.camel@hvost>
<AANLkTinKXhXnmHmUR1ZFkr0LcMTsCzXGy0bdYqtZXxcw@mail.gmail.com>
<4C3D7C2F020000250003353C@gw.wicourts.gov>
On Wed, 2010-07-14 at 08:58 -0500, Kevin Grittner wrote:
> Scott Marlowe <scott.marlowe@gmail.com> wrote:
> > Hannu Krosing <hannu@2ndquadrant.com> wrote:
> >> One example where you need a separate connection pool is pooling
> >> really large number of connections, which you may want to do on
> >> another host than the database itself is running.
> >
> > Definitely. Often it's best placed on the individual webservers
> > that are making requests, each running its own pool.
>
> Each running its own pool? You've just made a case for an
> admissions policy based on active database transactions or active
> queries (or both) on the server having a benefit when used with this
> pooling arrangement. This collection of pools can't know when the
> CPUs have enough to keep them busy and adding more will degrade
> performance.
I guess this setup is for OLTP load (read "lots of short transactions
with low timeout limits"), where you can just open 2-5 connections per
CPU for mostly-in-memory database, maybe a little more when disk
accesses are involved. If you have more, then they just wait a few
milliseconds, if you have less, you don't have anything else to run
anyway.
--
Hannu Krosing http://www.2ndQuadrant.com
PostgreSQL Scalability and Availability
Services, Consulting and Training
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To: pgsql-performance@postgresql.org
Cc: hannu@2ndquadrant.com, Kevin.Grittner@wicourts.gov, scott.marlowe@gmail.com, sgendler@ideasculptor.com, tgl@sss.pgh.pa.us
Subject: Re: Need help in performance tuning.
In-Reply-To: <1279119291.3888.5.camel@hvost>
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