Struct Decorrelator 

pub struct Decorrelator { /* private fields */ }

Subquery decorrelation optimizer

Implementations

impl Decorrelator

pub fn new() -> Decorrelator

Create a new decorrelator

pub fn analyze( &self, outer_refs: &[String], inner_cols: &[String], correlation_predicates: &[(String, String)], subquery_type: SubqueryKind, has_aggregation: bool, has_limit: bool, ) -> SubqueryAnalysis

Analyze a correlated subquery for decorrelation potential

pub fn estimate_speedup( &self, outer_cardinality: usize, inner_cardinality: usize, strategy: &DecorrelationStrategy, ) -> f64

Estimate cost improvement from decorrelation Returns the ratio of (correlated cost) / (decorrelated cost)

pub fn should_decorrelate( &self, outer_cardinality: usize, inner_cardinality: usize, strategy: &DecorrelationStrategy, ) -> bool

Check if decorrelation is worthwhile based on cardinality

impl Decorrelator

pub fn plan_rewrite( &mut self, analysis: &SubqueryAnalysis, aggregation_col: Option<&str>, ) -> Option<SubqueryRewrite>

Generate a rewrite plan for a decorrelatable subquery

Trait Implementations

impl Default for Decorrelator

fn default() -> Decorrelator

Returns the “default value” for a type.