Inside Microsoft® SQL Server™ 2005: T-SQL Querying

Index Tuning

This section covers index tuning, which is an important facet of query tuning. Indexes are sorting and searching structures. They reduce the need for I/O when looking for data and for sorting when certain elements in the plan need or can benefit from sorted data. While some aspects of tuning can improve performance by a modest percentage, index tuning can often improve query performance by orders of magnitude. Hence, if you’re in charge of tuning, learning about indexes in depth is time well spent. Here I’ll cover index tuning aspects that are relevant to these books, and at the end of the chapter I’ll point you to other resources where you can find more information.

I’ll start by describing table and index structures that are relevant ...