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11
Query Rewrite
This chapter begins Part III of this book, expanding on previous chapters to
cover more detail on query rewrite and parallel processing. Additionally,
Part III includes details of data warehouse loading and general physical
architecture, both as applicable to performance tuning. This chapter will
cover the specifics of query rewrite in detail, rather than why it is used, and
the tools used for verification. We will examine what query rewrite actually
is and how its processing speed and possible use can be improved upon. So
this chapter is divided into two parts. The first part explains how the opti-
mizer query rewrites in different ...