Inside Microsoft® SQL Server™ 2005: Query Tuning and Optimization

Summary

In this chapter, we’ve explained the basics of query processing in SQL Server. We’ve introduced iterators—the fundamental building blocks of query processing—and discussed how to view query plans in three different formats: text, graphical, and XML. We’ve covered many of the most common iterators, including the iterators that implement scans and seeks, joins, and aggregation. We’ve looked at more complex query plans including dynamic index seeks, index unions and intersection, and a variety of subquery examples. We’ve also explored how the query processor implements parallel query execution. All of the query plans that SQL Server supports are built from these and other basic operators.

The vast majority of the time, the SQL Server query ...