Re: UPDATEDs slowing SELECTs in a fully cached database

From: Ivan Voras <ivoras(at)freebsd(dot)org>
To: pgsql-performance(at)postgresql(dot)org
Subject: Re: UPDATEDs slowing SELECTs in a fully cached database
Date: 2011-07-12 15:13:03
Message-ID: ivho9v$6dp$1@dough.gmane.org
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On 12/07/2011 02:09, lars wrote:

> Oh, and iowait hovers around 20% when SELECTs are slow:
>
> avg-cpu: %user %nice %system %iowait %steal %idle
> 1.54 0.00 0.98 18.49 0.07 78.92
>
> When SELECTs are fast it looks like this:
> avg-cpu: %user %nice %system %iowait %steal %idle
> 8.72 0.00 0.26 0.00 0.00 91.01
>
> Note that this is a 12 core VM. So one core at 100% would show as 8.33%
> CPU.

Now only if you could do an "iostat -x" and show the output in both cases...

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