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

Class PruneCorrelatedJoinColumns

java.lang.Object

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

io.prestosql.sql.planner.iterative.rule.PruneCorrelatedJoinColumns

All Implemented Interfaces:

Rule<ProjectNode>

public class PruneCorrelatedJoinColumns
extends ProjectOffPushDownRule<CorrelatedJoinNode>

This rule restricts the outputs of CorrelatedJoinNode's input and subquery based on which CorrelatedJoinNode's output symbols are referenced.

A symbol from input can be pruned, when - it is not a referenced output symbol, - it is not a correlation symbol, - it is not present in join filter.

A symbol from subquery can be pruned, when - it is not a referenced output symbol, - it is not present in join filetr.

Note: this rule does not remove any symbols from the correlation list. This is responsibility of PruneCorrelatedJoinCorrelation rule.

Transforms:

 - Project (a, c)
      - CorrelatedJoin
          correlation: [corr]
          filter: a > d
          - Input (a, b, corr)
          - Subquery (c, d, e)
 

Into:

 - Project (a, c)
      - CorrelatedJoin
          correlation: [corr]
          filter: a > d
          - Project (a, corr)
              - Input (a, b, corr)
          - Project (c, d)
              - Subquery (c, d, e)
 

Nested Class Summary

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

Rule.Context, Rule.Result

Constructor Summary

Constructors

Constructor	Description
PruneCorrelatedJoinColumns()

Method Summary

Modifier and Type	Method	Description
protected Optional<PlanNode>	pushDownProjectOff(Rule.Context context, CorrelatedJoinNode correlatedJoinNode, 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

PruneCorrelatedJoinColumns

public PruneCorrelatedJoinColumns()

Method Detail

pushDownProjectOff

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

Specified by:

pushDownProjectOff in class ProjectOffPushDownRule<CorrelatedJoinNode>