> The value in user_tab_columns.density for letter_bin.prty_id is 0. > 000430560539754607. > Take a look at the screenshot http://bit.ly/6AwFE6 > The left-hand-side is OFE 10.2.0.4 and shows density used as 4.0482e- > 06. > Compare that with the ofe 10.1.0 version on the right and you'll see > it uses 4.3056e-04, which is stored in the data dictionary. > > Having said that, I'm not sure what to set the density of the column > to-I'd appreciate some help with this. As I said previously - you should set it to the value already shown in the dictionary for DENSITY which would be in this case the 4.3056e-04. The other value 4.0482e-06 is the NewDensity that is not visible from the dictionary. Setting it to the value should revert to the previous handling of density - picking up the one from the dictionary. Of course you could set it to different values then - if it helps to come up with a reasonable estimate for most of your queries. > Additionally, look at the highlighted Histogram section-HtBal vs > Frequency - could that be a clue? I think is is a side effect of the different optimizer code paths. > And finally, I uploaded a few examples of using the dynamic_sampling > hint using the simple-case query to > http://www.neilkodner.com/dynamic_sampling_results.txt > > Looks like dynamic_sampling didn't kick in until level 6. Possibly the sampling results are rejected with lower sampling levels - there are some sanity checks applied. This can be seen from the 10053 optimizer trace file. It would be interesting to see the EXPLAIN PLAN results with more complex queries - in particular those that used an suboptimal plan so far. Regards, Randolf Oracle related stuff blog: http://oracle-randolf.blogspot.com/ Co-author of the forthcoming "OakTable Expert Oracle Practices" book: http://www.apress.com/book/view/1430226684 http://www.amazon.com/Expert-Oracle-Practices-Database-Administration/dp/1430226684 ___________________________________________________________ Preisknaller: WEB.DE DSL Flatrate für nur 16,99 Euro/mtl.! http://produkte.web.de/go/02/ -- //www.freelists.org/webpage/oracle-l