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Re: [Fwd: more on 'high cpu...']

From: Alex Gorbachev <ag_at_oracloid.com>
Date: Mon, 2 Jul 2007 14:59:48 -0400
Message-ID: <c2213f680707021159x41480c0dvcdef98c6cf2e3c52@mail.gmail.com>


Joe,

I see you are still hoping the guesswork will work. :)

You didn't even provide text of the statement/view definition, execution plans, how you test it (in GUI tool fetching first few rows?). It's unlikely that someone will be able to provide qualified help trying to guess what's the problem.

It's already a while that you are troubleshooting this query without proper approach. You mentioned that you are trying to employ 10046/10053 but it sounds like you are still inclined to guess the resolution right away instead of troubleshooting.

You might consider providing details above to the list (as well as trace results). If you cannot do that due to security reason and cannot follow it yourself due lack of experience -- hire a qualified consultant. It should be few hours of work only.

For your education in the future you might consider couple books: - Optimizing Oracle Performance by Cary Millsap (profiling) - Cost-Based Oracle Fundamentals by Jonathan Lewis (CBO and execution plans)

Regards,
Alex

On 7/2/07, Joe Armstrong-Champ <joseph.armstrong-champ_at_tufts.edu> wrote:
> Let me rephrase. I know that distincts can cause a lot of sorting which
> in turn can cause high cpu. I guess I'm wondering if there is any work
> around for this? I'm searching for problems on distincts on metalink but
> other than old bugs I'm not coming up with much.
>
> -------- Original Message --------
> Subject: more on 'high cpu...'
> Date: Mon, 02 Jul 2007 11:34:33 -0400
> From: Joe Armstrong-Champ <joseph.armstrong-champ_at_tufts.edu>
> Organization: Tufts University
> To: ORACLE-L <oracle-l_at_freelists.org>
>
> I'm still doing the traces but in the meantime I thought I'd ask a
> follow up question. The query is selecting from a view. The view returns
> hundreds of rows relatively quickly. The query itself is selecting
> DISTINCT rows from the view. When I take out the distinct it returns
> almost instantaneously. With the distinct in it takes 40 - 50 secs. Does
> this ring a bell with anyone?
>
>
>
> --
> http://www.freelists.org/webpage/oracle-l
>
>
>

-- 
Best regards,
Alex Gorbachev, Oracle DBA Brewer, The Pythian Group
http://www.pythian.com/blogs/author/alex http://blog.oracloid.com
--
http://www.freelists.org/webpage/oracle-l
Received on Mon Jul 02 2007 - 13:59:48 CDT

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