Struct Optimizer 

pub struct Optimizer { /* private fields */ }

Query optimizer that applies optimization passes.

Implementations

impl Optimizer

pub fn new() -> Self

Creates a new optimizer with default passes.

The default passes are applied in this order:

1. NotSimplification - Simplify NOT expressions (double negation, De Morgan)
2. AndPredicatePass - Break down AND predicates into chained filters
3. CrossProductPass - Convert multi-way cross products to binary tree
4. ImplicitJoinsPass - Convert CrossProduct + Filter to Join
5. OuterJoinSimplification - Convert outer joins to inner when WHERE rejects NULL
6. PredicatePushdown - Push filters down the plan tree
7. JoinReorder - Reorder joins for better performance

Note: IndexSelection is not included by default because it requires ExecutionContext with index information. Use with_passes() to add it.

pub fn with_passes(passes: Vec<Box<dyn OptimizerPass>>) -> Self

Creates an optimizer with custom passes.

pub fn optimize(&self, plan: LogicalPlan) -> LogicalPlan

Optimizes a logical plan.

pub fn to_physical(&self, plan: LogicalPlan) -> PhysicalPlan

Converts a logical plan to a physical plan. Also applies physical plan optimizations (TopNPushdown).

Trait Implementations

impl Default for Optimizer

fn default() -> Self

Returns the “default value” for a type.