Package org.apache.drill.exec.physical.impl.TopN

Class TopNBatch

java.lang.Object

org.apache.drill.exec.record.AbstractRecordBatch<TopN>

org.apache.drill.exec.physical.impl.TopN.TopNBatch

All Implemented Interfaces:

AutoCloseable, Iterable<VectorWrapper<?>>, CloseableRecordBatch, RecordBatch, VectorAccessible

public class TopNBatch
extends AbstractRecordBatch<TopN>

Operator Batch which implements the TopN functionality. It is more efficient than (sort + limit) since unlike sort it doesn't have to store all the input data to sort it first and then apply limit on the sorted data. Instead internally it maintains a priority queue backed by a heap with the size being same as limit value.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	TopNBatch.SimpleSV4RecordBatch

Nested classes/interfaces inherited from class org.apache.drill.exec.record.AbstractRecordBatch

AbstractRecordBatch.BatchState

Nested classes/interfaces inherited from interface org.apache.drill.exec.record.RecordBatch

RecordBatch.IterOutcome

Field Summary

Fields inherited from class org.apache.drill.exec.record.AbstractRecordBatch

batchStatsContext, container, context, oContext, popConfig, state, stats, unionTypeEnabled

Fields inherited from interface org.apache.drill.exec.record.RecordBatch

MAX_BATCH_ROW_COUNT

Constructor Summary

Constructors

Constructor	Description
TopNBatch(TopN popConfig, FragmentContext context, RecordBatch incoming)

Method Summary

Modifier and Type	Method	Description
void	buildSchema()
protected void	cancelIncoming()
void	close()
static MappingSet	createLeftMappingSet()
static MappingSet	createMainMappingSet()
static PriorityQueue	createNewPriorityQueue(MappingSet mainMapping, MappingSet leftMapping, MappingSet rightMapping, List<Order.Ordering> orderings, VectorAccessible batch, boolean unionTypeEnabled, boolean codegenDump, int limit, BufferAllocator allocator, BatchSchema.SelectionVectorMode mode, FragmentContext context)
static MappingSet	createRightMappingSet()
void	dump()	Perform dump of this batch's state to logs.
int	getRecordCount()	Get the number of records.
SelectionVector2	getSelectionVector2()
SelectionVector4	getSelectionVector4()
WritableBatch	getWritableBatch()	Gets a writable version of this batch.
RecordBatch.IterOutcome	innerNext()
void	purgeAndResetPriorityQueue()	Handle schema changes during execution.

Methods inherited from class org.apache.drill.exec.record.AbstractRecordBatch

cancel, checkContinue, getContainer, getContext, getOutgoingContainer, getPopConfig, getRecordBatchStatsContext, getSchema, getValueAccessorById, getValueVectorId, isRecordBatchStatsLoggingEnabled, iterator, next, next, next, schemaChangeException, schemaChangeException

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Constructor Details

TopNBatch

public TopNBatch(TopN popConfig,
 FragmentContext context,
 RecordBatch incoming)
          throws OutOfMemoryException

Throws:

OutOfMemoryException

Method Details

getRecordCount

public int getRecordCount()

Description copied from interface: VectorAccessible

Get the number of records.

Returns:

number of records

getSelectionVector2

public SelectionVector2 getSelectionVector2()

Specified by:

getSelectionVector2 in interface VectorAccessible

Overrides:

getSelectionVector2 in class AbstractRecordBatch<TopN>

getSelectionVector4

public SelectionVector4 getSelectionVector4()

Specified by:

getSelectionVector4 in interface VectorAccessible

Overrides:

getSelectionVector4 in class AbstractRecordBatch<TopN>

close

public void close()

Specified by:

close in interface AutoCloseable

Overrides:

close in class AbstractRecordBatch<TopN>

buildSchema

public void buildSchema()

Overrides:

buildSchema in class AbstractRecordBatch<TopN>

innerNext

public RecordBatch.IterOutcome innerNext()

Specified by:

innerNext in class AbstractRecordBatch<TopN>

createMainMappingSet

public static MappingSet createMainMappingSet()

createLeftMappingSet

public static MappingSet createLeftMappingSet()

createRightMappingSet

public static MappingSet createRightMappingSet()

createNewPriorityQueue

public static PriorityQueue createNewPriorityQueue(MappingSet mainMapping,
 MappingSet leftMapping,
 MappingSet rightMapping,
 List<Order.Ordering> orderings,
 VectorAccessible batch,
 boolean unionTypeEnabled,
 boolean codegenDump,
 int limit,
 BufferAllocator allocator,
 BatchSchema.SelectionVectorMode mode,
 FragmentContext context)

purgeAndResetPriorityQueue

public void purgeAndResetPriorityQueue()

Handle schema changes during execution. 1. Purge existing batches 2. Promote newly created container for new schema. 3. Recreate priority queue and reset with coerced container.

getWritableBatch

public WritableBatch getWritableBatch()

Description copied from interface: RecordBatch

Gets a writable version of this batch. Takes over ownership of existing buffers.

Specified by:

getWritableBatch in interface RecordBatch

Overrides:

getWritableBatch in class AbstractRecordBatch<TopN>

cancelIncoming

protected void cancelIncoming()

Specified by:

cancelIncoming in class AbstractRecordBatch<TopN>

dump

public void dump()

Description copied from interface: RecordBatch

Perform dump of this batch's state to logs.