Re: An ancient mystery

From: Stefan Knecht <knecht.stefan_at_gmail.com>
Date: Sat, 22 Nov 2008 10:56:11 +0100
Message-ID: <486b2b610811220156k2d8335cbkf968ef89460d2113@mail.gmail.com>


Did someone perhaps turn on sql trace for the session, invalidating the plans ?

Don't remember off the top of my head if dbms_system was already there in 8i, but I'd assume there was a way of doing it ?

Stefan


Stefan P Knecht
Senior Consultant
Systems Engineering

OPITZ CONSULTING Schweiz GmbH
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CH-8800 Thalwil

Mobile +41-79-571 36 27
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OCP 9i/10g SCSA SCNA


On Fri, Nov 21, 2008 at 4:05 AM, Dennis Williams < oracledba.williams_at_gmail.com> wrote:

> List,
>
> The situation:
>
> Oracle 8.1.7.4 database on Solaris 8 (soon to be upgraded to 10g)
> Rule-based Optimizer
>
> A query which has run for years using an indexed access to a very large
> table (maybe 100 million rows)
> suddenly decides to use a full-table scan, shutting down a critical
> business process.
>
> Then after several hours, it switches back to using the index.
> All concerned claim that nothing changed before or after.
>
> Needless to say the business users are nervous. They think maybe the
> database grew beyond some limit.
>
> Can anyone think of an explanation?
>
> Thanks,
> Dennis Williams
>

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Received on Sat Nov 22 2008 - 03:56:11 CST

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