org.apache.drill.exec.physical.impl.unnest

Class UnnestImpl

java.lang.Object

org.apache.drill.exec.physical.impl.unnest.UnnestImpl

All Implemented Interfaces:

Unnest

public class UnnestImpl
extends Object
implements Unnest

Contains the actual unnest operation. Unnest is a simple transfer operation in this implementation. Additionally, unnest produces an implicit rowId column that allows unnest to output batches with many rows of incoming data being unnested in a single call to innerNext(). Downstream blocking operators need to be aware of this rowId column and include the rowId as the sort or group by key. This class follows the pattern of other operators that generate code at runtime. Normally this class would be abstract and have placeholders for doSetup and doEval. Unnest however, doesn't require code generation so we can simply implement the code in a simple class that looks similar to the code gen templates used by other operators but does not implement the doSetup and doEval methods.

Constructor Summary

Constructors

Constructor and Description
UnnestImpl()

Method Summary

Modifier and Type	Method and Description
void	close()
RepeatedValueVector	getUnnestField()
void	resetGroupIndex() Reset the index at which the incoming vector is being processed.
void	setOutputCount(int outputCount) Set the maximum number of values allowed in the output.
void	setRowIdVector(org.apache.drill.exec.vector.IntVector v) Set the vector for the rowId implicit column
void	setUnnestField(RepeatedValueVector unnestField) Set the field to be unnested
void	setup(FragmentContext context, RecordBatch incoming, RecordBatch outgoing, List<TransferPair> transfers)
String	toString()
int	unnestRecords(int recordCount) Performs the actual unnest operation.

Methods inherited from class java.lang.Object

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

Constructor Detail

UnnestImpl

public UnnestImpl()

Method Detail

setUnnestField

public void setUnnestField(RepeatedValueVector unnestField)

Description copied from interface: Unnest

Set the field to be unnested

Specified by:

setUnnestField in interface Unnest

getUnnestField

public RepeatedValueVector getUnnestField()

Specified by:

getUnnestField in interface Unnest

setOutputCount

public void setOutputCount(int outputCount)

Description copied from interface: Unnest

Set the maximum number of values allowed in the output.

Specified by:

setOutputCount in interface Unnest

setRowIdVector

public void setRowIdVector(org.apache.drill.exec.vector.IntVector v)

Description copied from interface: Unnest

Set the vector for the rowId implicit column

Specified by:

setRowIdVector in interface Unnest

unnestRecords

public final int unnestRecords(int recordCount)

Description copied from interface: Unnest

Performs the actual unnest operation.

Specified by:

unnestRecords in interface Unnest

Returns:

number of values in output

setup

public final void setup(FragmentContext context,
                        RecordBatch incoming,
                        RecordBatch outgoing,
                        List<TransferPair> transfers)
                 throws SchemaChangeException

Specified by:

setup in interface Unnest

Throws:

SchemaChangeException

resetGroupIndex

public void resetGroupIndex()

Description copied from interface: Unnest

Reset the index at which the incoming vector is being processed. Called every time a new batch comes in.

Specified by:

resetGroupIndex in interface Unnest

close

public void close()

Specified by:

close in interface Unnest

toString

public String toString()

Overrides:

toString in class Object