Re: oracle 11g uses more CPU than 10g
- From: joshuasingham <joshuasingham@xxxxxxxxx>
- To: eagle.f@xxxxxxxxx
- Date: Thu, 7 Mar 2013 14:02:35 +0800
Maybe you can share the execution plan any changes from the nested loop
leading table from 10g to 11g or have you ran tanel poder snapper to see if
there is any changes in metrics (maybe delayed block cleanout) , also
please bear in mind that 11g has adaptive cursor sharing which can cause
high version count (parsing time) that may cause high cpu increase from 10g
Regards
Joshua
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On Thu, Mar 7, 2013 at 12:54 AM, Eagle Fan <eagle.f@xxxxxxxxx> wrote:
> Hi Kurt:
> Thank you for looking into this.
>
> We are using Sun T4-1 server. OS version is s10s_u10wos_17b.
>
> On Wed, Mar 6, 2013 at 10:25 PM, Kurt Van Meerbeeck <kurtvm@xxxxxxxxxx
> >wrote:
>
> > Are you by any chance using IBM AIX ?
> >
> > if so - see Bug 12596494 : GENERALLY HIGHER CPU USAGE IN 11.2.0.2 THAN
> > 10.2.0.4
> > and Bug 11689561 : HASH JOIN SLOWER IN 11.2 COMPARED TO 10.2 ON AIX
> >
> > cheers,
> > Kurt
> >
> > ----- Original Message -----
> > From: "Eagle Fan" <eagle.f@xxxxxxxxx>
> > To: oracle-l@xxxxxxxxxxxxx
> > Sent: Wednesday, March 6, 2013 10:36:44 AM
> > Subject: oracle 11g uses more CPU than 10g
> >
> > hi:
> > The databases was upgraded from 10204 to 11203 version. After upgrade, we
> > found that the CPU increased more than 30%.
> >
> > Compare the top SQLs CPU time before and after upgrade, I can see big
> > difference (15%~35%):
> >
> >
> >
> > But buffer gets don't have much difference.
> >
> > These SQLs are very simple PK lookup & Nest Loop SQLs.
> >
> > Does anybody know why the CPU per execution is increased so much?
> >
> > Thanks.
> >
> > Eagle Fan (www.dbafan.com)
> >
> >
> > --
> > //www.freelists.org/webpage/oracle-l
> >
> >
>
>
> --
> Eagle Fan (www.dbafan.com)
>
>
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