Tuning By cardinality Estimates
Date: Fri, 6 Mar 2009 09:41:39 +0000 (GMT)
I am trying to tune a query which is attached along with the plan. In some of the steps the estimated cardinality and actual rows is way off .
esp step 7,8,9,10,11
As a result of the wrong cardinality estimation instead of a hash join the optimizer chooses Nested Loops and the query takes almost 7 minutes to complete.
I resort to use_hash hint and the query completes in 2 minutes.
My question how do i make the optimizer aware of the correct cardinalities. I have collected stats fresh .
-- http://www.freelists.org/webpage/oracle-lReceived on Fri Mar 06 2009 - 03:41:39 CST
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