RE: RULE hint better sometimes after 10.2.0.3 upgrade

I'm not aware of any specific CBO issues between 10.1 and 10.2, but you
might want to have a look at this list of common issues for 8i-to-10g
upgrades since possibly some of the changes mentioned didn't occur until
10.2:  http://www.freelists.org/archives/oracle-l/07-2006/msg00516.html
 
Beyond that, I'd recommend to BAAG
(http://www.battleagainstanyguess.com/baag/) and I think the best way to
do that is look at 10046, and possibly 10053, traces of your problem
queries running on 10.1.0.5 and 10.2.0.3 and identify the key
differences.
 
Regards,
Brandon

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