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

Class PushDownDereferenceThroughJoin

java.lang.Object

io.prestosql.sql.planner.iterative.rule.PushDownDereferenceThroughJoin

All Implemented Interfaces:

Rule<ProjectNode>

public class PushDownDereferenceThroughJoin
extends Object
implements Rule<ProjectNode>

Transforms:

  Project(A_X := f1(A.x), G := f2(A_Y.z), E := f3(B))
    Join(A_Y = C_Y) => [A, B]
      Project(A_Y := A.y, A, B)
          Source(A, B)
      Project(C_Y := C.y)
          Source(C, D)
  

to:

  Project(A_X := f1(symbol), G := f2(A_Y.z), E := f3(B))
    Join(A_Y = C_Y) => [symbol, B]
      Project(symbol := A.x, A_Y := A.y, A, B)
        Source(A, B)
      Project(C_Y := C.y)
        Source(C, D)
 

Pushes down dereference projections through JoinNode. Excludes dereferences on symbols being used in join criteria 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
PushDownDereferenceThroughJoin(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

PushDownDereferenceThroughJoin

public PushDownDereferenceThroughJoin(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>