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ReuseExchangeAndSubquery Physical Optimization

ReuseExchangeAndSubquery is a physical query optimization.

ReuseExchangeAndSubquery is part of the preparations batch of physical query plan rules and is executed when QueryExecution is requested for the optimized physical query plan.

ReuseExchangeAndSubquery is a Catalyst rule for transforming physical query plans (Rule[SparkPlan]).

Executing Rule

apply(
  plan: SparkPlan): SparkPlan

apply is a noop (and simply returns the given SparkPlan unchanged) when neither the spark.sql.exchange.reuse nor the spark.sql.execution.reuseSubquery are enabled.

apply requests the SparkPlan to transformUpWithPruning any physical operator with EXCHANGE or PLAN_EXPRESSION tree pattern:

apply is part of the Rule abstraction.

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