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Re: different explain plan on production & test DB

From: Daniel Morgan <damorgan_at_x.washington.edu>
Date: Mon, 22 Mar 2004 08:35:42 -0800
Message-ID: <1079973318.138484@yasure>


Joe wrote:

> Hi,
>
> Our production database has been copied to our test database a while
> ago, so the contents should be rather similar regarding to number of
> rows etc.
>
> For a heavy SQL I get a completely different explain plan on test than
> on production. What are possible reasons??
>
> - indexes seem to be identicatal
> - statistics are up to date
> ...
>
>
> thanks in advance,
> Joe

Oracle versions and patch levels the same?

Are statistics being obtained in both cases with DBMS_STATS or is one using ANALYZE?

Differences in machine hardware such as CPUs

Differences in initialization parameters

-- 
Daniel Morgan
http://www.outreach.washington.edu/ext/certificates/oad/oad_crs.asp
http://www.outreach.washington.edu/ext/certificates/aoa/aoa_crs.asp
damorgan_at_x.washington.edu
(replace 'x' with a 'u' to reply)
Received on Mon Mar 22 2004 - 10:35:42 CST

Original text of this message

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