Re: Usage up to 50% CPU

From: Magnus Hagander
Subject: Re: Usage up to 50% CPU
Date: ,
Msg-id: 20070427081350.GD12895@svr2.hagander.net
(view: Whole thread, Raw)
In response to: Re: Usage up to 50% CPU  ("Andres Retzlaff")
Responses: Re: Usage up to 50% CPU  (Shane Ambler)
List: pgsql-performance

Tree view

Usage up to 50% CPU  ("Andres Retzlaff", )
 Re: Usage up to 50% CPU  (Magnus Hagander, )
  Re: Usage up to 50% CPU  ("Andres Retzlaff", )
   Re: Usage up to 50% CPU  (Magnus Hagander, )
    Re: Usage up to 50% CPU  (Shane Ambler, )
     Re: Usage up to 50% CPU  (Michael Stone, )
      Re: Usage up to 50% CPU  ("Andres Retzlaff", )

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



pgsql-performance by date:

From: Jim Nasby
Date:
Subject: Re: What`s wrong with JFS configuration?
From: Michael Stone
Date:
Subject: Re: Feature Request --- was: PostgreSQL Performance Tuning