MissingIndexes refers to potentially missing indexes that may benefit the query's performance, as identified by the Query Optimizer during query compilation. During the compilation process, which we discussed in the Query compilation essentials section of Chapter 2, Understanding Query Processing, SQL Server matches existing indexes where any of the columns required for the query predicates, aggregates, and output are present. Then it chooses to access the existing index or set of indexes that minimize the cost of access to the required columns. In other words, which index or set of indexes are the cheapest to read data from.
As this matching process occurs, SQL Server can identify whether the current set of indexes already ...
