Optimizer architecture
The Query Optimizer contains many optimization phases that each perform different functions. The different phases help the Query Optimizer perform the highest-value operations earliest in the optimization process.
The major phases in the optimization of a query, as shown in Figure 11-14, are as follows:
Simplification
Trivial plan
Auto-stats create/update
Exploration/implementation (phases)
Convert to executable plan
Figure 11-14. Query Optimizer pipeline.
Before optimization
The SQL Server query processor performs several steps before the actual optimization process begins. These transformations help shape the tree into a form that’s ...
Get Microsoft SQL Server 2012 Internals now with the O’Reilly learning platform.
O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.
