There's a good document about this two interesting parameters:

http://www.evdbt.com/SearchIntelligenceCBO.doc

and also see "asktom"

http://asktom.oracle.com/pls/ask/f?p=4950:8:308736813964790489::NO::F4950_P8_DISPLAYID,F4950_P8_CRITERIA:6601251003901,



======= At 2003-06-16, 04:37:00 you wrote: =======

>The answer is found in the Jonathan Lewis book "Building Efficient Databases".
>You should set OPTIMIZER_INDEX_COST_ADJ and OPTIMIZER_INDEX_CACHING. 
>Explanation:
>It is realistic to expect a part of an index to be cached and it is also 
>realistic to expect the index access to be somewhat cheaper then the table
>access. These two parameters give the same slant toward the index access path 
>and nested loops path as RBO. For the rest, buy Jonathan's book.
>
>On 2003.06.16 02:54, Hussain Ahmed Qadri wrote:
>> Hi,
>> We have two DBs, a production and a development, identical query was running
>> very quickly on the Development and very slowly on the Production. Both have
>> the similar structures, same number of indexes and everything. When I
>> checked the explain plan, I found out that on the Production DB, it was
>> doing a FTS on a couple of tables and was doing an Index scan on the
>> Development server. The only difference was that the tables on the
>> Production were ANALYZED.
>> To confirm my theory, I analyzed the tables on Development and it started
>> doing a FTS there as well hence slowing the query down. I know the
>> optimizer, after analyzing, would have chosen the better path in its own
>> sense but its not producing the desired result and it is taking ages now.
>> is there any way to undo that?
>> 
>> Regards,
>> 
>> Hussain Ahmed Qadri
>> DBA
>> SKMCH&RC
>> 
>
>-- 
>Mladen Gogala
>Oracle DBA
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>Author: Mladen Gogala
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= = = = = = = = = = = = = = = = = = = =
                        

Best regards.                            
Zhai Jingmin
[EMAIL PROTECTED]
2003-06-16




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Please see the official ORACLE-L FAQ: http://www.orafaq.net
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Author: Zhai Jingmin
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