RE: Better cardinality estimate when dialing optimizer_features_enable back

  • From: "Allen, Brandon" <Brandon.Allen@xxxxxxxxxxx>
  • To: "nkodner@xxxxxxxxx" <nkodner@xxxxxxxxx>, oracle-l-freelists <oracle-l@xxxxxxxxxxxxx>
  • Date: Tue, 24 Nov 2009 09:53:10 -0700

Have you considered just creating a stored outline (or sql profile if you have 
the tuning pack) to lock in your favorite explain plan?

Why would you want to create histograms on all indexed columns?  You might want 
to try removing all histograms on the columns involved with this query to see 
if that helps, or only gather histograms for columns with skewonly.

I think it might be helpful if you can provide the output of "select * from 
table(dbms_xplan.display_cursor(3841154485,0,'IOSTATS LAST'));", if this is the 
query you're trying to tune, but you'll need to turn on a 10046 trace for the 
query in order to gather plan level stats.

Regards,
Brandon


________________________________
Privileged/Confidential Information may be contained in this message or 
attachments hereto. Please advise immediately if you or your employer do not 
consent to Internet email for messages of this kind. Opinions, conclusions and 
other information in this message that do not relate to the official business 
of this company shall be understood as neither given nor endorsed by it.

Other related posts: