Re: optimizer_features_enable difference between 9.2.0.1/9..2.0.3/9.2.0.6?

"chao_ping" <zhuchao_at_gmail.com> wrote in message news:1121245490.311244.79640_at_g44g2000cwa.googlegroups.com...
>I have a case where in 9.2.0.3, the oracle was choosing bitmap access
> for btree index and it is not a good plan.
> I opened the same database with same parameter and in 9.2.0.5,, the
> oracle is using desired common btree index range scan, and it is faster
> and less cpu used. So it should be a CBO bug. But I was unable to find
> any clue in metalink.
>
>
> Lewis, When will your Cost Based oracle be published? is it a book, or
> some new whitepaper?
>
> Thanks
>

That's probably a bug fix that doesn't merit being included in the bugs list for the version - or perhaps it appears as something obscure like "bitmap cost underestimated in certain circumstances".

It's a book - Volume 1 is 150,000 words, covering the basics of CBO.

-- 
Regards

Jonathan Lewis

Now waiting on the publishers:    Cost Based Oracle - Volume 1

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