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Explaining Duplicate Indexes

Kevin Hill will be shocked and amazed that I finally linked to him again:

Duplicate indexes are those that exactly match the Key and Included columns.  That’s easy.

Possible duplicate indexes are those that very closely match Key/Included columns.

Why do you care?
Indexes have to be maintained. When I say that, most people immediately think of Reorganizing, rebuilding and updating statistics, and they are not wrong.

Click through for a great explanation of what “duplicate” indexes are, as well as ways to find them. If you’re searching for dupes, I’d recommend a couple blog posts from Kim Tripp as well on whether an index is really a duplicate and how to remove duplicate indexes.