In this dialog, you can enable/disable two features of the Execution Engine that optimize the execution of queries:
The cost-based optimizations. See section Cost-Based Optimization.
The Automatic simplification of queries. If enabled, the Execution Engine tries to simplify the queries before executing them. The goal is to decrease the number of operations in the Query plan and increase the number of operations that are delegated to the data sources. This optimization is enabled by default. The section Automatic Simplification of Queries explains how this feature works.
The Data movement optimization. See section Data Movement.