impact of changing optimizer_features_enable

all,

i have a funny things about how oracle given execution plan.

now my db is 10.2.0.3 on itanium 64bit.
when tried *.optimizer_features_enable from 10.2 until 9.2 , the report was not much different (so slow). but when change to *.optimizer_features_enable=8.1.7, it amazingly so so so fast....

so, does anyone have experiences about changing the above parameter and the impact to the applications?

thanks for your sharing...

-- 
regards
ujang
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