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Home -> Community -> Usenet -> c.d.o.server -> Re: index distinctiveness question.
This is an old answer (maybe not valid anymore with so many oracle releases having come and gone but), the answer is: it doesn't make any noticable difference from a performance aspect. The bigger question is: which index will be used more often. I was at an oracle conference many many years ago, somebody studied this exact question. He demonstrated empirically that there was no difference to be measured. Both indexes performed equally well under all his test scenarios. If your us of the index is both columns all the time then the order is generally not important. If however, you may be taking advantage of leading portion scans of the index then pick the column that you can use most ofter (assuming it gets used at all). Received on Thu Aug 02 2001 - 12:15:51 CDT