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Re: Imported DB runs SLOWER on faster machine

From: Niall Litchfield <n-litchfield_at_audit-commission.gov.uk>
Date: Tue, 23 Jul 2002 15:46:49 +0100
Message-ID: <3d3d6c5a$0$237$ed9e5944@reading.news.pipex.net>


"Vladimir M. Zakharychev" <bob_at_dpsp-yes.com> wrote in message news:ahj6oj$feo$1_at_babylon.agtel.net...
> "Daniel Morgan" <dmorgan_at_exesolutions.com> wrote in message
> news:3D3C9301.93124C13_at_exesolutions.com...
>
> > I could add a lot of additional items to your list of two. All of which
> > have to do with tuning. But the most glaring thing missing from your
> > posting is that you didn't run DBMS_STATS to analyze tables and indexes.
> > So, if that is the case, the CBO is just making wild guesses or out on
> > vacation.
>
> Daniel is probably right - you don't have any statistics collected after
import
> and thus you either get FTS or index access where inappropriate. Also,
your
> db_block_buffers may be set too low resulting in excessive physical i/o.

I agree that Daniel is right. However by default you *do* get stats on import - just estimated stats. I know this because moving an 816 export to an 817 instance *always* gives a dbms_stats error on import. Ignoring this and reanalyzing works just fine.

--
Niall Litchfield
Oracle DBA
Audit Commission UK
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Received on Tue Jul 23 2002 - 09:46:49 CDT

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