Why the concept of missing index groups is provided in SQL Server?

Question

I know about missing indexes, and that each index belongs to a missing index group which has a unique handle identifier. I want to know why groups are useful when we can just deal with individual missing indexes and what category or attribute of an index puts multiple missing indexes in the same group(cause there is usually one index in a group). Why it is comfortable to keep several missing indexes in the same group?

Thanks for your time!

Answer 1

This was a planned feature that never was implemented (the group concept), but the meta-data (DMV structure) is still there.

• igelr: If I will not use this feature(because it is not fully implemented) why do I need metadata about it?
• Tibor Karaszi: The DMVs were designed to accommodate this feature. But it was never realized. But if MS were to re-design the DMVs now, they would break backwards compatibility.
• combinatorist: So, reading between the lines, these views have relevant data about (missing) indexes, but the term group in their name and columns relating to the group concept are meaningless. In short, useful information was put there that likely could have been included as additional columns in the plain missing index details view.