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

Class PushDownDereferencesThroughTopN

java.lang.Object

io.prestosql.sql.planner.iterative.rule.PushDownDereferencesThroughTopN

All Implemented Interfaces:

Rule<ProjectNode>

public class PushDownDereferencesThroughTopN
extends Object
implements Rule<ProjectNode>

Transforms:

  Project(D := f1(A.x), E := f2(B.x), G := f3(C))
      TopN(orderBy = [B])
          Source(A, B, C)
  

to:

  Project(D := f1(symbol), E := f2(B.x), G := f3(C))
      TopN(orderBy = [B])
          Project(A, B, C, symbol := A.x)
              Source(A, B, C)
 

Pushes down dereference projections through TopN. Excludes dereferences on symbols in ordering scheme to avoid data replication, since these symbols cannot be pruned.

Nested Class Summary

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

Rule.Context, Rule.Result

Constructor Summary

Constructors

Constructor	Description
PushDownDereferencesThroughTopN(TypeAnalyzer typeAnalyzer)

Method Summary

Modifier and Type	Method	Description
Rule.Result	apply(ProjectNode projectNode, Captures captures, Rule.Context context)
Pattern<ProjectNode>	getPattern()	Returns a pattern to which plan nodes this rule applies.

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

PushDownDereferencesThroughTopN

public PushDownDereferencesThroughTopN(TypeAnalyzer typeAnalyzer)

Method Detail

getPattern

public Pattern<ProjectNode> getPattern()

Description copied from interface: Rule

Returns a pattern to which plan nodes this rule applies.

Specified by:

getPattern in interface Rule<ProjectNode>

apply

public Rule.Result apply(ProjectNode projectNode,
                         Captures captures,
                         Rule.Context context)

Specified by:

apply in interface Rule<ProjectNode>