From: Kevin Grittner <Kevin.Grittner@wicourts.gov>
To: Ryan Hansen <ryan.hansen@brightbuilders.com>
To: pgsql-performance@postgresql.org <pgsql-performance@postgresql.org>
To: Scott Carey <scott@richrelevance.com>
Subject: Re: Memory Allocation
Date: Wed, 26 Nov 2008 17:09:15 -0600
Message-ID: <492D82BB.EE98.0025.0@wicourts.gov> (raw)
In-Reply-To: <BDFBB77C9E07BE4A984DAAE981D19F961ACA1F1ADC@EXVMBX018-1.exch018.msoutlookonline.net>
References: <011101c95013$b6fca0a0$24f5e1e0$@hansen@brightbuilders.com>
<BDFBB77C9E07BE4A984DAAE981D19F961ACA1F1ADC@EXVMBX018-1.exch018.msoutlookonline.net>
>>> Scott Carey <scott@richrelevance.com> wrote:
> Set swappiness to 0 or 1.
We recently converted all 72 remote county databases from 8.2.5 to
8.3.4. In preparation we ran a test conversion of a large county over
and over with different settings to see what got us the best
performance. Setting swappiness below the default degraded
performance for us in those tests for identical data, same hardware,
no other changes.
Our best guess is that code which really wasn't getting called got
swapped out leaving more space in the OS cache, but that's just a
guess. Of course, I'm sure people would not be recommending it if
they hadn't done their own benchmarks to confirm that this setting
actually improved things in their environments, so the lesson here is
to test for your environment when possible.
-Kevin
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To: pgsql-performance@postgresql.org
Cc: Kevin.Grittner@wicourts.gov, ryan.hansen@brightbuilders.com, scott@richrelevance.com
Subject: Re: Memory Allocation
In-Reply-To: <492D82BB.EE98.0025.0@wicourts.gov>
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