> Would it help that I have optimizer_dynamic_setting at 2 at the > database level? I tried using a dynamic_sampling hint with a value of > 4; that didn't make a difference on the cardinality estimate. As pointed out by Robert - I wouldn't recommend changing the global level, for two reasons: - Potentially affects other queries that might change their execution plan not for the better - Dynamic Sampling gets only get activated under certain circumstances if statistics have been gathered There is a difference between the meaning of the level of Dynamic Sampling between Session/Cursor and Table level. For testing purposes I would recommend using it on Table level as already outlined - this means explicitly mentioning the table alias in the DYNAMIC_SAMPLING hint. If you don't specify the table alias this will be Dynamic Sampling on cursor level - level 4 very likely would not activate Dynamic Sampling at all with your statistics in place and the predicates used. So if you want to test this: - Use the DYNAMIC_SAMPLING hint with the table alias: DYNAMIC_SAMPLING(LETTER_BIN, <level>). This will activate Dynamic Sampling on the alias LETTER_BIN even with statistics in place to check for selectivity estimates - Check the EXPLAIN PLAN output -> In the "Notes" section you need to see "Dynamic Sampling used..." If it doesn't change the estimate, increase the level step by step, at last with level 10 the estimates need to get close to reality, obviously this is not reasonable, but it confirms that it works in general. For further details you can run a 10053 optimizer trace which will tell you the details about the Dynamic Sampling performed and the decisions of the optimizer to use or discard the results of the sampling. Robert: According to the provided information Dynamic Sampling is here not the culprit - the majority of time is spent on the actual execution, not the parse step. 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 ______________________________________________________ GRATIS für alle WEB.DE-Nutzer: Die maxdome Movie-FLAT! Jetzt freischalten unter http://movieflat.web.de -- //www.freelists.org/webpage/oracle-l