RE: Oracle CBO question

Thanks for the replies, I believe I have the proper response.  

A research project was not the intention. If the premise were true, I would imagine someone on the list would know and could answer immediately. The responses indicate for the most part that it is indeed untrue, and that the developer should verify his source or do some due diligence before requesting the same from the DBA.  

(although I suspect he thought I knew the answer off the top of my head as well...). From the sounds of his questions though, something else is probably going wrong with his queries.    

Sincerely,  

Joel Patterson
Database Administrator
joel.patterson_at_crowley.com
x72546
904 727-2546

From: Arul Ramachandran [mailto:contactarul_at_gmail.com] Sent: Thursday, June 07, 2007 9:53 AM
To: Patterson, Joel
Cc: oracle-l_at_freelists.org
Subject: Re: Oracle CBO question  

I'd like to know where the consultant developer got this information :-)

This can't be true, I've been working on CRM application where most queries are at the very least 25 way joins. No special CBO settings done for them.

Arul

On 6/7/07, Joel.Patterson_at_crowley.com <Joel.Patterson_at_crowley.com > wrote:

I have received a question from a consultant developer - below. Can anyone answer?  

I was once told that the CBO can only handle a certain number of tables in a query (16 iirc). Do you know what the CBO does when there are more? Try to optimize based on knowledge of the first 16 tables in the Where clause?    

-- 
Arul 


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