org.eigenbase.rel
Class JoinRel

java.lang.Object
  org.eigenbase.rel.AbstractRelNode
      org.eigenbase.rel.JoinRelBase
          org.eigenbase.rel.JoinRel

All Implemented Interfaces:

Cloneable, RelNode

public final class JoinRel
extends JoinRelBase

A JoinRel represents two relational expressions joined according to some condition.

Some rules:

• ExtractJoinFilterRule converts an inner join to a filter on top of a cartesian inner join.
• FennelCartesianJoinRule implements a JoinRel as a cartesian product.

Version:

$Id: //open/dev/farrago/src/org/eigenbase/rel/JoinRel.java#27 $

Author:

jhyde

Field Summary

private boolean	semiJoinDone
private List<RelDataTypeField>	systemFieldList

Fields inherited from class org.eigenbase.rel.JoinRelBase

condition, joinType, left, right, variablesStopped

Fields inherited from class org.eigenbase.rel.AbstractRelNode

digest, id, nextId, rowType, traits

Fields inherited from interface org.eigenbase.rel.RelNode

emptyArray

Constructor Summary

JoinRel(RelOptCluster cluster, RelNode left, RelNode right, RexNode condition, JoinRelType joinType, Set<String> variablesStopped)
Creates a JoinRel.

JoinRel(RelOptCluster cluster, RelNode left, RelNode right, RexNode condition, JoinRelType joinType, Set<String> variablesStopped, boolean semiJoinDone, List<RelDataTypeField> systemFieldList)
Creates a JoinRel, flagged with whether it has been translated to a semi-join.

Method Summary

JoinRel	clone() Clones this RelNode.
void	explain(RelOptPlanWriter pw)
List<RelDataTypeField>	getSystemFieldList() Returns a list of system fields that will be prefixed to output row type.
boolean	isSemiJoinDone() Returns whether this JoinRel has already spawned a SemiJoinRel via AddRedundantSemiJoinRule.

Methods inherited from class org.eigenbase.rel.JoinRelBase

_isValid, childrenAccept, computeSelfCost, createJoinType, deriveJoinRowType, deriveRowType, estimateJoinedRows, getChildExps, getCondition, getInputs, getJoinType, getLeft, getRight, getRows, getVariablesStopped, registerStoppedVariable, replaceInput, setVariablesStopped

Methods inherited from class org.eigenbase.rel.AbstractRelNode

cloneTraits, collectVariablesSet, collectVariablesUsed, computeDigest, getCluster, getCollationList, getConvention, getCorrelVariable, getDescription, getDigest, getExpectedInputRowType, getId, getInput, getOrCreateCorrelVariable, getQuery, getRelTypeName, getRowType, getTable, getTraits, inheritTraitsFrom, isAccessTo, isDistinct, isValid, onRegister, recomputeDigest, register, registerCorrelVariable, setCorrelVariable, toString

Methods inherited from class java.lang.Object

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

Field Detail

semiJoinDone

private final boolean semiJoinDone

systemFieldList

private List<RelDataTypeField> systemFieldList

Constructor Detail

JoinRel

public JoinRel(RelOptCluster cluster,
               RelNode left,
               RelNode right,
               RexNode condition,
               JoinRelType joinType,
               Set<String> variablesStopped)

Creates a JoinRel.

Parameters:

cluster - Cluster

left - Left input

right - Right input

condition - Join condition

joinType - Join type

variablesStopped - Set of names of variables which are set by the LHS and used by the RHS and are not available to nodes above this JoinRel in the tree

JoinRel

public JoinRel(RelOptCluster cluster,
               RelNode left,
               RelNode right,
               RexNode condition,
               JoinRelType joinType,
               Set<String> variablesStopped,
               boolean semiJoinDone,
               List<RelDataTypeField> systemFieldList)

Creates a JoinRel, flagged with whether it has been translated to a semi-join.

Parameters:

cluster - Cluster

left - Left input

right - Right input

condition - Join condition

joinType - Join type

variablesStopped - Set of names of variables which are set by the LHS and used by the RHS and are not available to nodes above this JoinRel in the tree

semiJoinDone - Whether this join has been translated to a semi-join

systemFieldList - List of system fields that will be prefixed to output row type; typically empty but must not be null

See Also:

isSemiJoinDone()

Method Detail

clone

public JoinRel clone()

Description copied from interface: RelNode

Clones this RelNode.

Traits of the RelNode must be explicitly cloned, using AbstractRelNode.inheritTraitsFrom(AbstractRelNode), as the RelNode may have traits of which it has no knowledge. Example implementation:

     public MyRelNode clone()
     {
         MyRelNode clone = new MyRelNode(...);
         clone.inheritTraitsFrom(this);
         return clone;
     }
 

N.B.: This method must be overridden whenever an existing, concrete RelNode is extended. Otherwise, calling clone() will produce a differently typed RelNode, resulting in invalid or incorrect query plans.

Specified by:

clone in interface RelNode

Specified by:

clone in class AbstractRelNode

Returns:

a clone of this RelNode

explain

public void explain(RelOptPlanWriter pw)

Specified by:

explain in interface RelNode

Overrides:

explain in class JoinRelBase

isSemiJoinDone

public boolean isSemiJoinDone()

Returns whether this JoinRel has already spawned a SemiJoinRel via AddRedundantSemiJoinRule.

Returns:

whether this join has already spawned a semi join

getSystemFieldList

public List<RelDataTypeField> getSystemFieldList()

Description copied from class: JoinRelBase

Returns a list of system fields that will be prefixed to output row type.

Overrides:

getSystemFieldList in class JoinRelBase

Returns:

list of system fields