org.apache.pig.backend.hadoop.executionengine.physicalLayer.relationalOperators
Class POUnion

java.lang.Object
  org.apache.pig.impl.plan.Operator<PhyPlanVisitor>
      org.apache.pig.backend.hadoop.executionengine.physicalLayer.PhysicalOperator
          org.apache.pig.backend.hadoop.executionengine.physicalLayer.relationalOperators.POUnion

All Implemented Interfaces:

Serializable, Cloneable, Comparable<Operator>, Illustrable

public class POUnion
extends PhysicalOperator

The union operator that combines the two inputs into a single stream. Note that this doesn't eliminate duplicate tuples. The Operator will also be added to every map plan which processes more than one input. This just pulls out data from the piepline using the proposed single threaded shared execution model. By shared execution I mean, one input to the Union operator is called once and the execution moves to the next non-drained input till all the inputs are drained.

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.pig.backend.hadoop.executionengine.physicalLayer.PhysicalOperator

PhysicalOperator.OriginalLocation

Field Summary

Fields inherited from class org.apache.pig.backend.hadoop.executionengine.physicalLayer.PhysicalOperator

alias, illustrator, input, inputAttached, inputs, lineageTracer, outputs, parentPlan, pigLogger, requestedParallelism, res, resultType

Fields inherited from class org.apache.pig.impl.plan.Operator

mKey

Constructor Summary

POUnion(OperatorKey k)

POUnion(OperatorKey k, int rp)

POUnion(OperatorKey k, int rp, List<PhysicalOperator> inp)

POUnion(OperatorKey k, List<PhysicalOperator> inp)

Method Summary

void	clearDone()
Result	getNextTuple() The code below, tries to follow our single threaded shared execution model with execution being passed around each non-drained input
Tuple	illustratorMarkup(Object in, Object out, int eqClassIndex) input tuple mark up to be illustrate-able
String	name()
void	setInputs(List<PhysicalOperator> inputs)
boolean	supportsMultipleInputs() Indicates whether this operator supports multiple inputs.
boolean	supportsMultipleOutputs() Indicates whether this operator supports multiple outputs.
void	visit(PhyPlanVisitor v) Visit this node with the provided visitor.

Methods inherited from class org.apache.pig.backend.hadoop.executionengine.physicalLayer.PhysicalOperator

addOriginalLocation, addOriginalLocation, attachInput, clone, cloneHelper, detachInput, getAlias, getAliasString, getIllustrator, getInputs, getLogger, getNext, getNextBigDecimal, getNextBigInteger, getNextBoolean, getNextDataBag, getNextDataByteArray, getNextDateTime, getNextDouble, getNextFloat, getNextInteger, getNextLong, getNextMap, getNextString, getOriginalLocations, getPigLogger, getReporter, getRequestedParallelism, getResultType, isAccumStarted, isAccumulative, isBlocking, isInputAttached, processInput, reset, setAccumEnd, setAccumStart, setAccumulative, setIllustrator, setParentPlan, setPigLogger, setReporter, setRequestedParallelism, setResultType

Methods inherited from class org.apache.pig.impl.plan.Operator

compareTo, equals, getOperatorKey, getProjectionMap, hashCode, regenerateProjectionMap, rewire, toString, unsetProjectionMap

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

POUnion

public POUnion(OperatorKey k)

POUnion

public POUnion(OperatorKey k,
               int rp)

POUnion

public POUnion(OperatorKey k,
               List<PhysicalOperator> inp)

POUnion

public POUnion(OperatorKey k,
               int rp,
               List<PhysicalOperator> inp)

Method Detail

setInputs

public void setInputs(List<PhysicalOperator> inputs)

Overrides:

setInputs in class PhysicalOperator

visit

public void visit(PhyPlanVisitor v)
           throws VisitorException

Description copied from class: Operator

Visit this node with the provided visitor. This should only be called by the visitor class itself, never directly.

Specified by:

visit in class PhysicalOperator

Parameters:

v - Visitor to visit with.

Throws:

VisitorException - if the visitor has a problem.

name

public String name()

Specified by:

name in class Operator<PhyPlanVisitor>

supportsMultipleInputs

public boolean supportsMultipleInputs()

Description copied from class: Operator

Indicates whether this operator supports multiple inputs.

Specified by:

supportsMultipleInputs in class Operator<PhyPlanVisitor>

Returns:

true if it does, otherwise false.

supportsMultipleOutputs

public boolean supportsMultipleOutputs()

Description copied from class: Operator

Indicates whether this operator supports multiple outputs.

Specified by:

supportsMultipleOutputs in class Operator<PhyPlanVisitor>

Returns:

true if it does, otherwise false.

clearDone

public void clearDone()

getNextTuple

public Result getNextTuple()
                    throws ExecException

The code below, tries to follow our single threaded shared execution model with execution being passed around each non-drained input

Overrides:

getNextTuple in class PhysicalOperator

Throws:

ExecException

illustratorMarkup

public Tuple illustratorMarkup(Object in,
                               Object out,
                               int eqClassIndex)

Description copied from interface: Illustrable

input tuple mark up to be illustrate-able

Parameters:

in - input tuple

out - output tuple before wrapped in ExampleTuple

eqClassIndex - index into equivalence classes in illustrator

Returns:

tuple