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SQL Anywhere 11.0.1 (Français) » SQL Anywhere Server - SQL Usage » Query Processing » Query optimization and execution » How the optimizer works

 

Underlying assumptions of the optimizer

Several assumptions underlie the design direction and philosophy of the SQL Anywhere query optimizer. You can improve the quality or performance of your own applications through an understanding of the optimizer's decisions. These assumptions provide a context in which you may understand the information contained in the remaining sections.


Minimal administration work
Optimize for first row or for entire result set
Optimize for mixed or OLAP workload
Statistics are present and correct
Indexes can be used to satisfy a predicate
Virtual memory is a scarce resource
The memory governor