Re: CBO problem

My guess is that it has nothing to do with IOT and only indirectly with automatic statistics gathering. Unless you changed the default method_opt, the 10g automatic statistics gathering job will gather histograms on all columns used in predicates (at least that is an improvement over the "for all indexed columns" nonsense). If your queries include bind variables you could see the result of different plans being generated due to bind variable peeking at parse time - and then that plan being used for all other BV until the plan ages out or gets invalidated.

Quoting Nirmalya Das <nirmalya_at_hln.com>:

>
> Some queries (which involves some Index Organized Tables) runs like a charm
> for
> some time and once in a while will a get a bad execution plan and will
> exceed
> the CPU limit assigned in the user profile.
>
> We use the "Automatic Statistics Gathering" to collect statistics.
>

-- 
regards

Wolfgang Breitling
Oracle 7,8,8i,9i OCP DBA
Centrex Consulting Corporation
www.centrexcc.com

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