Re: Unique index or not

Hi, there's no difference between an UNIQUE or DUPS index for the optimizer. If you would have a lot of duplicates inside your index tree, the number of leaf pages would be less than if you have only unique values. The optimizer is only interested in the number of leaf pages, the number of index levels, and in the selectivity of the filter conditions. I suppose that you need the composite index for an ORDER BY or a Key-Only Read. For this query it makes no difference. Bye Stefan