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Re: Why isn't Oracle Using My Index

From: Riyaj Shamsudeen <>
Date: Fri, 22 Dec 2006 11:20:16 -0600
Message-ID: <>

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Hi Dan

    Yes, I know and that's the first thing we tried ;-) In fact, William changed the whole statement, still no 10053 trace. Same 10053 trace worked correctly for me in 10g, even after setting nls_sort and nls_comp parameters.

    Then, I thought, may be somehow he had index stats alone, but no table stats [ I have seen use of RBO in these cases ]. That was not the case either. Optimizer_mode was set to choose and definitely CBO must have been used.


Daniel W. Fink wrote:
> 10053 traces are only generated when the statement is hard parsed. I
> use comments, change case, etc. to make sure the statement is
> considered 'new' by the optimizer.
> Riyaj Shamsudeen wrote:
>> Hi All
>> Due to some issues with mail server DNS entries, my posting to
>> the list bounces. I am trying other options ;-)
>> So, I was working with William off-line and here are the highlights:
>> 1. I thought, autotrace had dumped incorrect statistics, asked
>> for 10046/10053 trace files.
>> 2. 10053 trace files were never generated for this SQL. Still,
>> don't understand, why ? I think, this must be a bug with 9i. I can't
>> test it.
>> 3. explain plan filter predicates clearly pointed out the issue.
>> Of course, metalink documents mentioned here and reference books
>> are showing the issues. I recreated the issue before telling William.
>> And Wolfgang, as usual, has done a wonderful job of recreating the
>> issue.

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Received on Fri Dec 22 2006 - 11:20:16 CST

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