org.teiid.query.processor.relational

Class MergeJoinStrategy

java.lang.Object

org.teiid.query.processor.relational.JoinStrategy

org.teiid.query.processor.relational.MergeJoinStrategy

Direct Known Subclasses:

EnhancedSortMergeJoinStrategy, NestedLoopJoinStrategy

public class MergeJoinStrategy
extends JoinStrategy

MergeJoinStrategy supports generalized Full, Left Outer, and Inner Joins (containing non-equi join criteria) as long as there is at least one equi-join criteria Additionally supports Semi and Anti-Semi Joins. These too allow for generalized non-equi join criteria. TODO: when there is no non-equi join criteria matching duplicates from the outer side can be output immediately TODO: semi joins should only output left tuples Support for Intersect and Except is controlled by the grouping flag, which changes comparisons to check for null equality.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	MergeJoinStrategy.SortOption

Field Summary

Fields

Modifier and Type	Field and Description
protected MergeJoinStrategy.SortOption	processingSortLeft
protected MergeJoinStrategy.SortOption	processingSortRight
protected boolean	singleMatch false if default processing, true if only a single outer match is allowed
protected MergeJoinStrategy.SortOption	sortLeft
protected MergeJoinStrategy.SortOption	sortRight

Fields inherited from class org.teiid.query.processor.relational.JoinStrategy

joinNode, leftSource, reserved, rightSource

Constructor Summary

Constructors

Constructor and Description
MergeJoinStrategy(MergeJoinStrategy.SortOption sortLeft, MergeJoinStrategy.SortOption sortRight, boolean grouping)

Method Summary

Modifier and Type	Method and Description
MergeJoinStrategy	clone()
void	close()
protected int	compare(List leftProbe, List rightProbe, int[] leftExpressionIndecies, int[] rightExpressionIndecies)
protected boolean	compareToPrevious(org.teiid.query.processor.relational.SourceState target)
static int	compareTuples(List<?> leftProbe, List<?> rightProbe, int[] leftExpressionIndecies, int[] rightExpressionIndecies, boolean nullEquals, boolean columnDiff) 0 if the values match positive if right is greater than left negative if left is greater than right In column diff mode, return -1 if the they are the same else return the index where they differ
String	getName()
void	initialize(JoinNode joinNode)
protected void	loadLeft()
protected void	loadRight()
protected void	process()
protected void	resetMatchState()
void	setProcessingSortLeft(boolean processingSortLeft)
void	setProcessingSortRight(boolean processingSortRight)
MergeJoinStrategy	singleMatch(boolean b) Optional flag for a left outer join to enforce the single row restriction of a scalar subquery
String	toString()

Methods inherited from class org.teiid.query.processor.relational.JoinStrategy

openLeft, openRight, outputTuple

Methods inherited from class java.lang.Object

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

Field Detail

sortLeft

protected MergeJoinStrategy.SortOption sortLeft

sortRight

protected MergeJoinStrategy.SortOption sortRight

singleMatch

protected boolean singleMatch

false if default processing, true if only a single outer match is allowed

processingSortLeft

protected MergeJoinStrategy.SortOption processingSortLeft

processingSortRight

protected MergeJoinStrategy.SortOption processingSortRight

Constructor Detail

MergeJoinStrategy

public MergeJoinStrategy(MergeJoinStrategy.SortOption sortLeft,
                         MergeJoinStrategy.SortOption sortRight,
                         boolean grouping)

Method Detail

clone

public MergeJoinStrategy clone()

Specified by:

clone in class JoinStrategy

See Also:

JoinStrategy.clone()

initialize

public void initialize(JoinNode joinNode)

Overrides:

initialize in class JoinStrategy

See Also:

JoinStrategy.initialize(org.teiid.query.processor.relational.JoinNode)

resetMatchState

protected void resetMatchState()

close

public void close()

Overrides:

close in class JoinStrategy

See Also:

JoinStrategy.close()

process

protected void process()
                throws TeiidComponentException,
                       TeiidProcessingException

Specified by:

process in class JoinStrategy

Throws:

TeiidComponentException

TeiidProcessingException

compareToPrevious

protected boolean compareToPrevious(org.teiid.query.processor.relational.SourceState target)
                             throws TeiidComponentException,
                                    TeiidProcessingException

Throws:

TeiidComponentException

TeiidProcessingException

compare

protected int compare(List leftProbe,
                      List rightProbe,
                      int[] leftExpressionIndecies,
                      int[] rightExpressionIndecies)

compareTuples

public static int compareTuples(List<?> leftProbe,
                                List<?> rightProbe,
                                int[] leftExpressionIndecies,
                                int[] rightExpressionIndecies,
                                boolean nullEquals,
                                boolean columnDiff)

0 if the values match positive if right is greater than left negative if left is greater than right In column diff mode, return -1 if the they are the same else return the index where they differ

Parameters:

leftProbe -

rightProbe -

leftExpressionIndecies -

rightExpressionIndecies -

nullEquals -

columnDiff -

Returns:

loadLeft

protected void loadLeft()
                 throws TeiidComponentException,
                        TeiidProcessingException

Overrides:

loadLeft in class JoinStrategy

Throws:

TeiidComponentException

TeiidProcessingException

loadRight

protected void loadRight()
                  throws TeiidComponentException,
                         TeiidProcessingException

Overrides:

loadRight in class JoinStrategy

Throws:

TeiidComponentException

TeiidProcessingException

setProcessingSortRight

public void setProcessingSortRight(boolean processingSortRight)

setProcessingSortLeft

public void setProcessingSortLeft(boolean processingSortLeft)

getName

public String getName()

toString

public String toString()

Overrides:

toString in class Object

See Also:

Object.toString()

singleMatch

public MergeJoinStrategy singleMatch(boolean b)

Optional flag for a left outer join to enforce the single row restriction of a scalar subquery