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Re: CPU_TIME > ELAPSED_TIME

From: Anjo Kolk <anjo.kolk_at_oraperf.com>
Date: Thu, 25 Oct 2007 00:29:16 +0200
Message-ID: <54973d5e0710241529j47dff6c3x7319b9f30af8cc97@mail.gmail.com>


The CPU time is really measured in Centi Seconds and multiplied with 10000 to be micro seconds. The elapsed time is really micro seconds. So you can get some interesting rounding errors :)

Anjo.

On 10/23/07, Eagle Fan <eagle.f_at_gmail.com> wrote:
>
> Hi:
>
> I have had the same problem before. From v$sql:
>
> Delta CPU_TIME > Delta Elapsed_time. The sql is very simple, it's doing
> "INDEX UNIQUE SCAN" using PK index.'
>
> How to explain this?
>
> Thanks
>
> SQL> select CPU_TIME,ELAPSED_TIME from v$sql where hash_value=1769575534;
>
> CPU_TIME ELAPSED_TIME
> ----------------------- -----------------------
> 71025140000 70448619327
>
> SQL> exec dbms_lock.sleep(300);
>
> PL/SQL procedure successfully completed.
>
> SQL> select CPU_TIME,ELAPSED_TIME from v$sql where hash_value=1769575534;
>
> CPU_TIME ELAPSED_TIME
> ----------------------- -----------------------
> 71030920000 70453943000
>
> SQL> select (71030920000-71025140000)/(70453943000-70448619327) from dual;
>
> (71030920000-71025140000)/(70453943000-70448619327)
> ---------------------------------------------------
> 1.08571657
>
>
>
> --
> Eagle Fan
>
> Oracle DBA

-- 
Anjo Kolk
Owner and Founder OraPerf Projects
tel:    +31-577-712000
mob: +31-6-55340888

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Received on Wed Oct 24 2007 - 17:29:16 CDT

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