Struct Optimizer 

pub struct Optimizer { /* private fields */ }

Transforms logical plans for faster execution.

Create with new(), then call optimize(). Use the builder methods to enable/disable specific optimizations.

Implementations

impl Optimizer

pub fn new() -> Self

Creates a new optimizer with default settings.

pub fn from_store(store: &LpgStore) -> Self

Creates an optimizer with cardinality estimates from the store’s statistics.

Pre-populates the cardinality estimator with per-label row counts and edge type fanout. Feeds per-edge-type degree stats, label cardinalities, and graph totals into the cost model for accurate estimation.

pub fn from_graph_store(store: &dyn GraphStore) -> Self

Creates an optimizer from any GraphStore implementation.

Unlike from_store, this does not call ensure_statistics_fresh() since external stores manage their own statistics. The store’s statistics() method is called directly.

pub fn with_filter_pushdown(self, enabled: bool) -> Self

Enables or disables filter pushdown.

pub fn with_join_reorder(self, enabled: bool) -> Self

Enables or disables join reordering.

pub fn with_projection_pushdown(self, enabled: bool) -> Self

Enables or disables projection pushdown.

pub fn with_cost_model(self, cost_model: CostModel) -> Self

Sets the cost model.

pub fn with_cardinality_estimator(self, estimator: CardinalityEstimator) -> Self

Sets the cardinality estimator.

pub fn with_selectivity_config(self, config: SelectivityConfig) -> Self

Sets the selectivity configuration for the cardinality estimator.

pub fn cost_model(&self) -> &CostModel

Returns a reference to the cost model.

pub fn cardinality_estimator(&self) -> &CardinalityEstimator

Returns a reference to the cardinality estimator.

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

Estimates the total cost of a plan by recursively costing the entire tree.

Walks every operator in the plan, computing cardinality at each level and summing the per-operator costs. Uses actual child cardinalities for join cost estimation rather than approximations.

pub fn estimate_cardinality(&self, plan: &LogicalPlan) -> f64

Estimates the cardinality of a plan.

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

Optimizes a logical plan.

Errors

Returns an error if optimization fails.

Trait Implementations

impl Default for Optimizer

fn default() -> Self

Returns the “default value” for a type.