Exactly. That's a place where CBO should have no trouble whatsoever making the right decision (index access). Cary Millsap Hotsos Enterprises, Ltd. http://www.hotsos.com Nullius in verba Hotsos Symposium 2007 / March 4-8 / Dallas Visit www.hotsos.com for curriculum and schedule details... ________________________________ From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Wolfgang Breitling Sent: Thursday, June 29, 2006 6:44 AM To: Laimutis.Nedzinskas@xxxxxxxxxxxxx Cc: oracle-l@xxxxxxxxxxxxx Subject: RE: full-scan vs index for "small" tables At 03:20 AM 6/29/2006, Laimutis Nedzinskas wrote: I can illustrate my point using one example (which seems to be one the the biggest CBO issues actually, discussed many times before): I have a "select where type='OPENED' " No need to say that type='OPENED' is 0.1% of all records, the rest are 'CLOSED'. I built a histogram. Value 'OPENED' happened not to be there because... the were no records with type='OPENED' at the time. Plan was full scan of course. That is not my experience at all. If the value in the predicate is NOT in the (frequency) histogram then in my experience hat is synonymous for "very rare" for the CBO and it uses the index. From all you are saying I get the impression that you are using a different CBO from the one I am using. Regards Wolfgang Breitling Centrex Consulting Corporation www.centrexcc.com