Package org.apache.flink.streaming.runtime.tasks

Class OperatorChain<OUT,OP extends StreamOperator<OUT>>

java.lang.Object

org.apache.flink.streaming.runtime.tasks.OperatorChain<OUT,OP>

Type Parameters:

OUT - The type of elements accepted by the chain, i.e., the input type of the chain's main operator.

All Implemented Interfaces:

Closeable, AutoCloseable, BoundedMultiInput

Direct Known Subclasses:

FinishedOperatorChain, RegularOperatorChain

public abstract class OperatorChain<OUT,OP extends StreamOperator<OUT>>
extends Object
implements BoundedMultiInput, Closeable

The OperatorChain contains all operators that are executed as one chain within a single StreamTask.

The main entry point to the chain is it's mainOperator. mainOperator is driving the execution of the StreamTask, by pulling the records from network inputs and/or source inputs and pushing produced records to the remaining chained operators.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	OperatorChain.ChainedSource	Wrapper class to access the chained sources and their's outputs.

Field Summary

Fields

Modifier and Type	Field	Description
protected final Map<StreamConfig.SourceInputConfig,OperatorChain.ChainedSource>	chainedSources
protected final org.apache.flink.shaded.guava32.com.google.common.io.Closer	closer
protected final FinishedOnRestoreInput	finishedOnRestoreInput
protected final StreamOperatorWrapper<?,?>	firstOperatorWrapper
protected boolean	isClosed
protected final WatermarkGaugeExposingOutput<StreamRecord<OUT>>	mainOperatorOutput
protected final StreamOperatorWrapper<OUT,OP>	mainOperatorWrapper	For iteration, StreamIterationHead and StreamIterationTail used for executing feedback edges do not contain any operators, in which case, mainOperatorWrapper and tailOperatorWrapper are null.
protected final int	numOperators
protected final OperatorEventDispatcherImpl	operatorEventDispatcher
protected final RecordWriterOutput<?>[]	streamOutputs
protected final StreamOperatorWrapper<?,?>	tailOperatorWrapper

Constructor Summary

Constructors

Constructor	Description
OperatorChain(StreamTask<OUT,OP> containingTask, RecordWriterDelegate<SerializationDelegate<StreamRecord<OUT>>> recordWriterDelegate)

Method Summary

Modifier and Type	Method	Description
void	abortCheckpoint(long checkpointId, CheckpointException cause)
void	alignedBarrierTimeout(long checkpointId)
void	broadcastEvent(AbstractEvent event)
void	broadcastEvent(AbstractEvent event, boolean isPriorityEvent)
void	close()	This method releases all resources of the record writer output.
void	closeAllOperators()	Execute StreamOperator.close() of each operator in the chain of this StreamTask.
abstract void	dispatchOperatorEvent(OperatorID operator, org.apache.flink.util.SerializedValue<OperatorEvent> event)
abstract void	endInput(int inputId)	Ends the main operator input specified by inputId).
abstract void	finishOperators(StreamTaskActionExecutor actionExecutor, StopMode stopMode)	Closes all operators in a chain effect way.
void	flushOutputs()	This method should be called before finishing the record emission, to make sure any data that is still buffered will be sent.
Iterable<StreamOperatorWrapper<?,?>>	getAllOperators()	Returns an Iterable which traverses all operators in forward topological order.
protected Iterable<StreamOperatorWrapper<?,?>>	getAllOperators(boolean reverse)	Returns an Iterable which traverses all operators in forward or reverse topological order.
OperatorChain.ChainedSource	getChainedSource(StreamConfig.SourceInputConfig sourceInput)
List<Output<StreamRecord<?>>>	getChainedSourceOutputs()
Input	getFinishedOnRestoreInputOrDefault(Input defaultInput)
OP	getMainOperator()
WatermarkGaugeExposingOutput<StreamRecord<OUT>>	getMainOperatorOutput()
int	getNumberOfOperators()
OperatorEventDispatcher	getOperatorEventDispatcher()
StreamTaskSourceInput<?>	getSourceTaskInput(StreamConfig.SourceInputConfig sourceInput)
List<StreamTaskSourceInput<?>>	getSourceTaskInputs()
RecordWriterOutput<?>[]	getStreamOutputs()
protected StreamOperator<?>	getTailOperator()
abstract void	initializeStateAndOpenOperators(StreamTaskStateInitializer streamTaskStateInitializer)	Initialize state and open all operators in the chain from tail to heads, contrary to StreamOperator.close() which happens heads to tail (see finishOperators(StreamTaskActionExecutor, StopMode)).
boolean	isClosed()
abstract boolean	isTaskDeployedAsFinished()
abstract void	notifyCheckpointAborted(long checkpointId)
abstract void	notifyCheckpointComplete(long checkpointId)
abstract void	notifyCheckpointSubsumed(long checkpointId)
abstract void	prepareSnapshotPreBarrier(long checkpointId)
protected void	sendAcknowledgeCheckpointEvent(long checkpointId)
protected void	snapshotChannelStates(StreamOperator<?> op, ChannelStateWriter.ChannelStateWriteResult channelStateWriteResult, OperatorSnapshotFutures snapshotInProgress)
abstract void	snapshotState(Map<OperatorID,OperatorSnapshotFutures> operatorSnapshotsInProgress, CheckpointMetaData checkpointMetaData, CheckpointOptions checkpointOptions, Supplier<Boolean> isRunning, ChannelStateWriter.ChannelStateWriteResult channelStateWriteResult, CheckpointStreamFactory storage)

Methods inherited from class java.lang.Object

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

Field Details

streamOutputs

protected final RecordWriterOutput<?>[] streamOutputs

mainOperatorOutput

protected final WatermarkGaugeExposingOutput<StreamRecord<OUT>> mainOperatorOutput

mainOperatorWrapper

@Nullable
protected final StreamOperatorWrapper<OUT,OP extends StreamOperator<OUT>> mainOperatorWrapper

For iteration, StreamIterationHead and StreamIterationTail used for executing feedback edges do not contain any operators, in which case, mainOperatorWrapper and tailOperatorWrapper are null.

Usually first operator in the chain is the same as mainOperatorWrapper, but that's not the case if there are chained source inputs. In this case, one of the source inputs will be the first operator. For example the following operator chain is possible:

 first
      \
      main (multi-input) -> ... -> tail
      /
 second
 

Where "first" and "second" (there can be more) are chained source operators. When it comes to things like closing, stat initialisation or state snapshotting, the operator chain is traversed: first, second, main, ..., tail or in reversed order: tail, ..., main, second, first

firstOperatorWrapper

@Nullable
protected final StreamOperatorWrapper<?,?> firstOperatorWrapper

tailOperatorWrapper

@Nullable
protected final StreamOperatorWrapper<?,?> tailOperatorWrapper

chainedSources

protected final Map<StreamConfig.SourceInputConfig,OperatorChain.ChainedSource> chainedSources

numOperators

protected final int numOperators

operatorEventDispatcher

protected final OperatorEventDispatcherImpl operatorEventDispatcher

closer

protected final org.apache.flink.shaded.guava32.com.google.common.io.Closer closer

finishedOnRestoreInput

@Nullable
protected final FinishedOnRestoreInput finishedOnRestoreInput

isClosed

protected boolean isClosed

Constructor Details

OperatorChain

public OperatorChain(StreamTask<OUT,OP> containingTask,
 RecordWriterDelegate<SerializationDelegate<StreamRecord<OUT>>> recordWriterDelegate)

Method Details

isTaskDeployedAsFinished

public abstract boolean isTaskDeployedAsFinished()

dispatchOperatorEvent

public abstract void dispatchOperatorEvent(OperatorID operator,
 org.apache.flink.util.SerializedValue<OperatorEvent> event)
                                    throws org.apache.flink.util.FlinkException

Throws:

org.apache.flink.util.FlinkException

prepareSnapshotPreBarrier

public abstract void prepareSnapshotPreBarrier(long checkpointId)
                                        throws Exception

Throws:

Exception

endInput

public abstract void endInput(int inputId)
                       throws Exception

Ends the main operator input specified by inputId).

Specified by:

endInput in interface BoundedMultiInput

Parameters:

inputId - the input ID starts from 1 which indicates the first input.

Throws:

Exception

initializeStateAndOpenOperators

public abstract void initializeStateAndOpenOperators(StreamTaskStateInitializer streamTaskStateInitializer)
                                              throws Exception

Initialize state and open all operators in the chain from tail to heads, contrary to StreamOperator.close() which happens heads to tail (see finishOperators(StreamTaskActionExecutor, StopMode)).

Throws:

Exception

finishOperators

public abstract void finishOperators(StreamTaskActionExecutor actionExecutor,
 StopMode stopMode)
                              throws Exception

Closes all operators in a chain effect way. Closing happens from heads to tail operator in the chain, contrary to StreamOperator.open() which happens tail to heads (see initializeStateAndOpenOperators(StreamTaskStateInitializer)).

Throws:

Exception

notifyCheckpointComplete

public abstract void notifyCheckpointComplete(long checkpointId)
                                       throws Exception

Throws:

Exception

notifyCheckpointAborted

public abstract void notifyCheckpointAborted(long checkpointId)
                                      throws Exception

Throws:

Exception

notifyCheckpointSubsumed

public abstract void notifyCheckpointSubsumed(long checkpointId)
                                       throws Exception

Throws:

Exception

snapshotState

public abstract void snapshotState(Map<OperatorID,OperatorSnapshotFutures> operatorSnapshotsInProgress,
 CheckpointMetaData checkpointMetaData,
 CheckpointOptions checkpointOptions,
 Supplier<Boolean> isRunning,
 ChannelStateWriter.ChannelStateWriteResult channelStateWriteResult,
 CheckpointStreamFactory storage)
                            throws Exception

Throws:

Exception

getOperatorEventDispatcher

public OperatorEventDispatcher getOperatorEventDispatcher()

broadcastEvent

public void broadcastEvent(AbstractEvent event)
                    throws IOException

Throws:

IOException

broadcastEvent

public void broadcastEvent(AbstractEvent event,
 boolean isPriorityEvent)
                    throws IOException

Throws:

IOException

alignedBarrierTimeout

public void alignedBarrierTimeout(long checkpointId)
                           throws IOException

Throws:

IOException

abortCheckpoint

public void abortCheckpoint(long checkpointId,
 CheckpointException cause)

closeAllOperators

public void closeAllOperators()
                       throws Exception

Execute StreamOperator.close() of each operator in the chain of this StreamTask. Closing happens from tail to head operator in the chain.

Throws:

Exception

getStreamOutputs

public RecordWriterOutput<?>[] getStreamOutputs()

getAllOperators

@VisibleForTesting
public Iterable<StreamOperatorWrapper<?,?>> getAllOperators()

Returns an Iterable which traverses all operators in forward topological order.

getAllOperators

protected Iterable<StreamOperatorWrapper<?,?>> getAllOperators(boolean reverse)

Returns an Iterable which traverses all operators in forward or reverse topological order.

getFinishedOnRestoreInputOrDefault

public Input getFinishedOnRestoreInputOrDefault(Input defaultInput)

getNumberOfOperators

public int getNumberOfOperators()

getMainOperatorOutput

public WatermarkGaugeExposingOutput<StreamRecord<OUT>> getMainOperatorOutput()

getChainedSource

public OperatorChain.ChainedSource getChainedSource(StreamConfig.SourceInputConfig sourceInput)

getChainedSourceOutputs

public List<Output<StreamRecord<?>>> getChainedSourceOutputs()

getSourceTaskInput

public StreamTaskSourceInput<?> getSourceTaskInput(StreamConfig.SourceInputConfig sourceInput)

getSourceTaskInputs

public List<StreamTaskSourceInput<?>> getSourceTaskInputs()

flushOutputs

public void flushOutputs()
                  throws IOException

This method should be called before finishing the record emission, to make sure any data that is still buffered will be sent. It also ensures that all data sending related exceptions are recognized.

Throws:

IOException - Thrown, if the buffered data cannot be pushed into the output streams.

close

public void close()
           throws IOException

This method releases all resources of the record writer output. It stops the output flushing thread (if there is one) and releases all buffers currently held by the output serializers.

This method should never fail.

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Throws:

IOException

getMainOperator

@Nullable
public OP getMainOperator()

getTailOperator

@Nullable
protected StreamOperator<?> getTailOperator()

snapshotChannelStates

protected void snapshotChannelStates(StreamOperator<?> op,
 ChannelStateWriter.ChannelStateWriteResult channelStateWriteResult,
 OperatorSnapshotFutures snapshotInProgress)

isClosed

public boolean isClosed()

sendAcknowledgeCheckpointEvent

protected void sendAcknowledgeCheckpointEvent(long checkpointId)