Summary

In this chapter, we looked at how SQL Server processes the queries that it receives from a client application. The most powerful and complex component of query processing is the query optimizer. We looked at the information that the optimizer uses to make its decisions about which indexes and which processing techniques should be used. Some of the most important information available to the optimizer is the statistics. Statistics can be automatically generated and maintained by SQL Server, and you can also manually update them.

We also looked at the caching of plans generated by the optimizer. SQL Server can cache and reuse plans not only from stored procedures, but also from ad hoc and autoparameterized queries. Because generation of query plans can be expensive, it is helpful to understand how and why query plans are reused and when they must be regenerated.



Inside Microsoft SQL Server 2000
Inside Microsoft SQL Server 2000
ISBN: 0735609985
EAN: 2147483647
Year: 2005
Pages: 179
Authors: Kalen Delaney

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