From: Kevin Grittner <Kevin.Grittner@wicourts.gov>
To: jd@commandprompt.com
Cc: pgsql-performance@postgresql.org
Subject: Re: Create and drop temp table in 8.3.4
Date: Thu, 06 Nov 2008 13:35:26 -0600
Message-ID: <4912F29E.EE98.0025.0@wicourts.gov> (raw)
In-Reply-To: <1225999071.1204.14.camel@jd-laptop.pragmaticzealot.org>
References: <4911957A.EE98.0025.0@wicourts.gov>
<4911D4DB.EE98.0025.0@wicourts.gov>
<4912EAFF.EE98.0025.0@wicourts.gov>
<1225999071.1204.14.camel@jd-laptop.pragmaticzealot.org>
>>> "Joshua D. Drake" <jd@commandprompt.com> wrote:
> On Thu, 2008-11-06 at 13:02 -0600, Kevin Grittner wrote:
>> the new kernel
>> defaulted to using write barriers, while the old kernel didn't.
Since
>> we have a BBU RAID controller, we will add nobarrier to the fstab
>> entries. This makes file creation and unlink each about 20 times
>> faster.
>
> Woah... which version of the kernel was old and new?
old:
kgrittn@DBUTL-PG:/var/pgsql/data/test> cat /proc/version
Linux version 2.6.5-7.287.3-bigsmp (geeko@buildhost) (gcc version 3.3.3
(SuSE Linux)) #1 SMP Tue Oct 2 07:31:36 UTC 2007
kgrittn@DBUTL-PG:/var/pgsql/data/test> uname -a
Linux DBUTL-PG 2.6.5-7.287.3-bigsmp #1 SMP Tue Oct 2 07:31:36 UTC 2007
i686 i686 i386 GNU/Linux
kgrittn@DBUTL-PG:/var/pgsql/data/test> cat /etc/SuSE-release
SUSE LINUX Enterprise Server 9 (i586)
VERSION = 9
PATCHLEVEL = 3
new:
kgrittn@SAWYER-PG:~> cat /proc/version
Linux version 2.6.16.60-0.27-smp (geeko@buildhost) (gcc version 4.1.2
20070115 (SUSE Linux)) #1 SMP Mon Jul 28 12:55:32 UTC 2008
kgrittn@SAWYER-PG:~> uname -a
Linux SAWYER-PG 2.6.16.60-0.27-smp #1 SMP Mon Jul 28 12:55:32 UTC 2008
x86_64 x86_64 x86_64 GNU/Linux
kgrittn@SAWYER-PG:~> cat /etc/SuSE-release
SUSE Linux Enterprise Server 10 (x86_64)
VERSION = 10
PATCHLEVEL = 2
To be clear, file create and unlink speeds are almost the same between
the two kernels without write barriers; the difference is that they
were in effect by default in the newer kernel.
-Kevin
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To: pgsql-performance@postgresql.org
Cc: Kevin.Grittner@wicourts.gov, jd@commandprompt.com
Subject: Re: Create and drop temp table in 8.3.4
In-Reply-To: <4912F29E.EE98.0025.0@wicourts.gov>
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