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Home -> Community -> Mailing Lists -> Oracle-L -> Re: stats and query plans
Hi!
It's probably because your optimizer_* parameters aren't configured properly. Check http://www.evdbt.com/SearchIntelligenceCBO.doc
Tanel.
hi
a very basic question
i have faced this issue a few times in the last couple of weeks. we have a few queries that seem to run remarkable well in rule based optimisation than in choose based optimisation. the queries, with all the object stats collected upto date, never returns a result while when i deleted all stats it returns a result in no time.The plans are diffrent and w/o stats indexes are being used.
when this happens in the same system what are the things i should check. is it not recommended that oracle CBO is the best way to go in performance tuning and query optimisations.then how come rule based turns out to be efficient.surely i havent generated 10053 trace and gone through it but it doesnt make sense why CBO falters. Logically speaking when rule based path gives a result,CBO should choose that explain plan.
can someone throw some light on this
thanks
sai
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Author: Tanel Poder
INET: tanel.poder.003_at_mail.ee
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