Yes, the problem is that you're doing an implicit conversion. If you use HEXTORAW() it should solve the problem. Try: select * from tab1 wnere raw_column = hextoraw('value'); Hope that helps, -Mark -- Mark J. Bobak Senior Oracle Architect ProQuest Information & Learning There is nothing so useless as doing efficiently that which shouldn't be done at all. -Peter F. Drucker, 1909-2005 ________________________________ From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Harvinder Singh Sent: Wednesday, February 14, 2007 2:12 PM To: oracle-l Subject: Optimizer not using index on raw column Hi, We have an unique index on raw(16) column but whenever we issue a query on this table optimizer is doing fullscan and not using the index but when I force index it works fine: Select * from tab1 where raw_column = 'value'; Is this expected behavior that when we refer RAW columns in query that Optimizer not use the index? Thanks --Harvinder