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Re: full-scan vs index for "small" tables

From: Ghassan Salem <salem.ghassan_at_gmail.com>
Date: Fri, 30 Jun 2006 11:11:20 +0200
Message-ID: <411d50f60606300211i11251e14s15447a68d700dfa7@mail.gmail.com>


Laimutis,
I have to disagree with you all the line. I hopefully Oracle will not listen and do what you're asking for.
If CBO is not good for you, it is good for others. It may not be good for everybody all the time, but RBO was not either, and would have never been. CBO is getting better by each version, and will continue to do so. As for being naiive and sticking with the 'vendor recommandations', well, the default init parameters are never meant to be 'recommendations', they are there just because you must have something to start your DB. There's no 'fits all' init.ora params, or statistics collection strategy, ....
Another point, I for one do not want Oracle to always use an index if it is there. You may create one index for a given purpose, even for a given query, but it may not be good for all queries.
and what about cases where you have 2 possible indexes, how can RBO choose between them?

rgds

On 6/30/06, Laimutis Nedzinskas <Laimutis.Nedzinskas_at_landsbanki.is> wrote:
>
> >From: Wolfgang Breitling
> >If you don't want this kind of surprise - or others related to statistics
> - take control of the statistics gathering.
>
> *YES* In the other words: drop all intelligence, drop all AUTO stuff
> (including ... CBO ... if possible)
>
>
> >You don't just take init.ora defaults, why would you accept the
> statistics gathering defaults?
>
> I humbly acknowledge - I am sorry. I was still na´ve enough to believe
> vendors recommendations are to be followed, at least sometimes.
>
>
> Thank you very much,
> Laimis N.
>
> Fyrirvari/Disclaimer
> http://www.landsbanki.is/disclaimer
> --
> http://www.freelists.org/webpage/oracle-l
>
>
>

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Received on Fri Jun 30 2006 - 04:11:20 CDT

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