Please see Query Optimizer in the Library User Guide

lib.rs:

DataFusion Optimizer

Contains rules for rewriting LogicalPlans

1. Analyzer applies AnalyzerRules to transform LogicalPlans to make the plan valid prior to the rest of the DataFusion optimization process (for example, TypeCoercion).

2. Optimizer applies OptimizerRules to transform LogicalPlans into equivalent, but more efficient plans.