Jonathan, Can you pls help me understand how did you figure out the foll.: - that the row for table is much larger than the row estimate for the index - the cost of the table visits have been added to the cost of the range scan Thanks. On Fri, Sep 14, 2012 at 6:54 PM, Jonathan Lewis <jonathan@xxxxxxxxxxxxxxxxxx > wrote: > > The fact that the row for the table is much larger than the row estimate > for the index used to get to it suggests that you didn't collect stats on > the hidden column underpinning the table when you created the index. The > plan may have changed the following morning because of an overnight stats > collection that rectified this mismatch. It's interesting, though that in > this case the cost of the table visits have been added to the cost of the > range scan - but perhaps that's a version thing. > > Regards > > Jonathan Lewis > http://jonathanlewis.wordpress.com/all_postings > > -- //www.freelists.org/webpage/oracle-l