Subject: Re: Ever Increasing IOWAIT
From: Mark Lewis <mark.lewis@mir3.com>
To: Ralph Mason <ralph.mason@telogis.com>
Cc: pgsql-performance@postgresql.org
In-Reply-To: <011b01c798d5$141365a0$3c3a30e0$@mason@telogis.com>
References: <011b01c798d5$141365a0$3c3a30e0$@mason@telogis.com>
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Organization: MIR3, Inc.
Date: Fri, 18 May 2007 06:58:03 -0700
Message-Id: <1179496683.31471.72.camel@archimedes>
Mime-Version: 1.0

You're not swapping are you?  One explanation could be that PG is
configured to think it has access to a little more memory than the box
can really provide, which forces it to swap once it's been running for
long enough to fill up its shared buffers or after a certain number of
concurrent connections are opened.

-- Mark Lewis

On Fri, 2007-05-18 at 10:45 +1200, Ralph Mason wrote:
> We have a database running on a 4 processor machine.  As time goes by
> the IO gets worse and worse peeking at about 200% as the machine loads
> up.
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> The weird thing is that if we restart postgres it=E2=80=99s fine for hour=
s but
> over time it goes bad again.
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> (CPU usage graph here
> http://www.flickr.com/photos/8347741@N02/502596262/ )  You can clearly
> see where the restart happens in the IO area
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> This is Postgres  8.1.4 64bit.
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> Anyone have any ideas?
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> Thanks
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> Ralph
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