Method optimize

datafusion/core/src/execution/session_state.rs:666–740

Optimizes the logical plan by applying optimizer rules.

(&self, plan: &LogicalPlan)

    /// Optimizes the logical plan by applying optimizer rules.
    pub fn optimize(&self, plan: &LogicalPlan) -> datafusion_common::Result<LogicalPlan> {
        if let LogicalPlan::Explain(e) = plan {
            let mut stringified_plans = e.stringified_plans.clone();

            // analyze & capture output of each rule
            let analyzer_result = self.analyzer.execute_and_check(
                e.plan.as_ref().clone(),
                &self.options(),
                |analyzed_plan, analyzer| {
                    let analyzer_name = analyzer.name().to_string();
                    let plan_type = PlanType::AnalyzedLogicalPlan { analyzer_name };
                    stringified_plans.push(analyzed_plan.to_stringified(plan_type));
                },
            );
            let analyzed_plan = match analyzer_result {
                Ok(plan) => plan,
                Err(DataFusionError::Context(analyzer_name, err)) => {
                    let plan_type = PlanType::AnalyzedLogicalPlan { analyzer_name };
                    stringified_plans
                        .push(StringifiedPlan::new(plan_type, err.to_string()));

                    return Ok(LogicalPlan::Explain(Explain {
                        verbose: e.verbose,
                        plan: Arc::clone(&e.plan),
                        explain_format: e.explain_format.clone(),
                        stringified_plans,
                        schema: Arc::clone(&e.schema),
                        logical_optimization_succeeded: false,
                    }));
                }
                Err(e) => return Err(e),
            };

            // to delineate the analyzer & optimizer phases in explain output
            stringified_plans
                .push(analyzed_plan.to_stringified(PlanType::FinalAnalyzedLogicalPlan));

            // optimize the child plan, capturing the output of each optimizer
            let optimized_plan = self.optimizer.optimize(
                analyzed_plan,
                self,
                |optimized_plan, optimizer| {
                    let optimizer_name = optimizer.name().to_string();
                    let plan_type = PlanType::OptimizedLogicalPlan { optimizer_name };
                    stringified_plans.push(optimized_plan.to_stringified(plan_type));
                },
            );
            let (plan, logical_optimization_succeeded) = match optimized_plan {
                Ok(plan) => (Arc::new(plan), true),
                Err(DataFusionError::Context(optimizer_name, err)) => {
                    let plan_type = PlanType::OptimizedLogicalPlan { optimizer_name };
                    stringified_plans
                        .push(StringifiedPlan::new(plan_type, err.to_string()));
                    (Arc::clone(&e.plan), false)
                }
                Err(e) => return Err(e),
            };