Package io.prestosql.sql.planner.iterative.rule

Class PruneExchangeColumns

java.lang.Object

io.prestosql.sql.planner.iterative.rule.ProjectOffPushDownRule<ExchangeNode>

io.prestosql.sql.planner.iterative.rule.PruneExchangeColumns

All Implemented Interfaces:

Rule<ProjectNode>

public class PruneExchangeColumns
extends ProjectOffPushDownRule<ExchangeNode>

This rule restricts the outputs of ExchangeNode based on which ExchangeNode's output symbols are either referenced by the parent node or used for partitioning, ordering or as a hash symbol by the ExchangeNode.

For each symbol removed from the output symbols list, the corresponding input symbols are removed from ExchangeNode's inputs lists.

Transforms:

 - Project (o1)
      - Exchange:
        outputs [o1, o2, o3, h]
        partitioning by (o2)
        hash h
        inputs [[a1, a2, a3, h1], [b1, b2, b3, h2]]
          - source [a1, a2, a3, h1]
          - source [b1, b2, b3, h2]
 

Into:

 - Project (o1)
      - Exchange:
        outputs [o1, o2, h]
        partitioning by (o2)
        hash h
        inputs [[a1, a2, h1], [b1, b2, h2]]
          - source [a1, a2, a3, h1]
          - source [b1, b2, b3, h2]
 

Nested Class Summary

Nested classes/interfaces inherited from interface io.prestosql.sql.planner.iterative.Rule

Rule.Context, Rule.Result

Constructor Summary

Constructors

Constructor	Description
PruneExchangeColumns()

Method Summary

Modifier and Type	Method	Description
protected Optional<PlanNode>	pushDownProjectOff(Rule.Context context, ExchangeNode exchangeNode, Set<Symbol> referencedOutputs)

Methods inherited from class io.prestosql.sql.planner.iterative.rule.ProjectOffPushDownRule

apply, getPattern

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface io.prestosql.sql.planner.iterative.Rule

isEnabled

Constructor Detail

PruneExchangeColumns

public PruneExchangeColumns()

Method Detail

pushDownProjectOff

protected Optional<PlanNode> pushDownProjectOff(Rule.Context context,
                                                ExchangeNode exchangeNode,
                                                Set<Symbol> referencedOutputs)

Specified by:

pushDownProjectOff in class ProjectOffPushDownRule<ExchangeNode>