Re: Usage up to 50% CPU

From: Magnus Hagander <magnus(at)hagander(dot)net>
To: Andres Retzlaff <andres_retzlaff(at)hotmail(dot)com>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: Usage up to 50% CPU
Date: 2007-04-27 08:13:50
Message-ID: 20070427081350.GD12895@svr2.hagander.net
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On Fri, Apr 27, 2007 at 08:10:48AM +0000, Andres Retzlaff wrote:
> Hi Magnus,
>
> in this case each CPU goes up to 50%, giveing me 50% total usage. I was
> specting as you say 1 query 100% cpu.
>
> Any ideas?

No. 1 query will only use 100% of *one* CPU, which means 50% total usage.
You need at least one query per CPU to reach full 100% of the whole system.
(Actually, you can get slightly above 50% since the query will run on one
CPU and the OS and autovacuum and bgwriter can run on the other. But it's
marginally)

//Magnus

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