you could use the dump function on the values to see if they are truly the same. joe _______________________________________ Joe Testa, Oracle Certified Professional (Work) 614-677-1668 (Cell) 614-312-6715 Interested in helping out your marriage? Ask me about "Weekend to Remember" Dec 11-13, 2009 here in Columbus. From: "Goulet, Richard" <Richard.Goulet@xxxxxxxxxxx> To: <Josh.Collier@xxxxxxxxxxxx>, <mark.powell@xxxxxxx>, <oracle-l@xxxxxxxxxxxxx> Date: 06/09/2009 02:23 PM Subject: RE: index doesn't contain duplicates Sent by: oracle-l-bounce@xxxxxxxxxxxxx Josh, One question & this one has taken me to the cleaners more times that I'd like to admit. The two rows that "appear" to be the same, are they of the same length? Here's an example of what I mean: Row1: 'DATAVALUE' Row2: 'DATAVALUE ' There is a very slight difference, in this case a trailing space that really does make the two rows different. Other characters that can cause similar problems is anything in the extended ascii character set which will show up like spaces. Dick Goulet Senior Oracle DBA PAREXEL International From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Josh Collier Sent: Tuesday, June 09, 2009 2:12 PM To: mark.powell@xxxxxxx; oracle-l@xxxxxxxxxxxxx Subject: RE: index doesn't contain duplicates Version 9208 The way the table was created was this.. Table was created with a CTAS Non-unique index was built Primary key was built on a column, specifying index created in step2. Enable novalidate. The data in question was inserted after the primary was in place. The plan that produces the incorrect results is a fast full scan on the non-unique index The plan that produces the correct result is a full tablescan on the table. We From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Powell, Mark D Sent: Tuesday, June 09, 2009 10:22 AM To: oracle-l@xxxxxxxxxxxxx Subject: RE: index doesn't contain duplicates Yes, the full Oracle version would be nice plus the select with plan the produces the proper results and one that does not. Things you can try: Run analyze index validate Run analyze table validate cascade (depending on results from above) Drop and re-create index -- Mark D Powell -- Phone (313) 592-5148 From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Josh Collier Sent: Tuesday, June 09, 2009 12:11 PM To: oracle-l@xxxxxxxxxxxxx Subject: index doesn't contain duplicates All, I have an table that has duplicate values for a column. I have a non-unique index on this column. When I run a query that uses a fast full scan to retrieve the rows, it only retrieves one of the two rows. When I force a full tablescan both of the rows come back. I have used all my sql tricks to try my best to determine if the value has trailining or leading non-printable characters and it doesn’t appear so. I have also moved the values into a varchar 11 field in another table, the value is 11 chars long. Both of the duplicate rows where accepted. Does anyone know of a bug or a reason why both of the rows wouldn’t appear in the index? Thanks for your time, Josh C.