RE: Query tuning exercise: what to look for in a 10053 trace

Yep, read them both - and saw his presentation at Hotsos :-) I'm not sure on this, but I think the join order will be a result of the estd cardinalities as well - with a NL join, it will start with the row source that it expects to return the smallest number of rows, then probe the other table for matching rows. So, if it underestimates the cardinality, then it will end up doing a lot more probing than it expected to do.

From: Schultz, Charles [mailto:sac_at_uillinois.edu] Sent: Tuesday, July 25, 2006 11:25 AM
To: Allen, Brandon; oracle-l_at_freelists.org Subject: RE: Query tuning exercise: what to look for in a 10053 trace

I see you have been reading his "tuning by cardinality feedback" paper. Or perhaps "under the hood..."? =)
I have read them, but it takes a long time for me to absorb the wonderful insights these guys have.  

From an academic standpoint, I am trying to figure out why the CBO is using a different join order - perhaps this is a vain and useless endeavor, but I am curious.

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