org.apache.flink.runtime.io.network.partition.ResultPartitionProvider Java Examples

private void testBufferWriting(ResultSubpartitionView view) throws IOException {
	// setup
	ResultPartitionProvider partitionProvider =
		(partitionId, index, availabilityListener) -> view;

	final InputChannelID receiverId = new InputChannelID();
	final PartitionRequestQueue queue = new PartitionRequestQueue();
	final SequenceNumberingViewReader reader = new SequenceNumberingViewReader(receiverId, queue);
	final EmbeddedChannel channel = new EmbeddedChannel(queue);

	reader.requestSubpartitionView(partitionProvider, new ResultPartitionID(), 0);

	// notify about buffer availability and encode one buffer
	reader.notifyDataAvailable();

	channel.runPendingTasks();

	Object read = channel.readOutbound();
	assertNotNull(read);
	if (read instanceof NettyMessage.ErrorResponse) {
		((NettyMessage.ErrorResponse) read).cause.printStackTrace();
	}
	assertThat(read, instanceOf(NettyMessage.BufferResponse.class));
	read = channel.readOutbound();
	assertNull(read);
}
 

@Test
public void testProducerFailedException() throws Exception {
	PartitionRequestQueue queue = new PartitionRequestQueue();

	ResultSubpartitionView view = new ReleasedResultSubpartitionView();

	ResultPartitionProvider partitionProvider =
		(partitionId, index, availabilityListener) -> view;

	EmbeddedChannel ch = new EmbeddedChannel(queue);

	CreditBasedSequenceNumberingViewReader seqView = new CreditBasedSequenceNumberingViewReader(new InputChannelID(), 2, queue);
	seqView.requestSubpartitionView(partitionProvider, new ResultPartitionID(), 0);
	// Add available buffer to trigger enqueue the erroneous view
	seqView.notifyDataAvailable();

	ch.runPendingTasks();

	// Read the enqueued msg
	Object msg = ch.readOutbound();

	assertEquals(msg.getClass(), NettyMessage.ErrorResponse.class);

	NettyMessage.ErrorResponse err = (NettyMessage.ErrorResponse) msg;
	assertTrue(err.cause instanceof CancelTaskException);
}
 

@Override
public void requestSubpartitionView(
	ResultPartitionProvider partitionProvider,
	ResultPartitionID resultPartitionId,
	int subPartitionIndex) throws IOException {

	synchronized (requestLock) {
		if (subpartitionView == null) {
			// This this call can trigger a notification we have to
			// schedule a separate task at the event loop that will
			// start consuming this. Otherwise the reference to the
			// view cannot be available in getNextBuffer().
			this.subpartitionView = partitionProvider.createSubpartitionView(
				resultPartitionId,
				subPartitionIndex,
				this);
		} else {
			throw new IllegalStateException("Subpartition already requested");
		}
	}
}
 

@Override
public void requestSubpartitionView(
	ResultPartitionProvider partitionProvider,
	ResultPartitionID resultPartitionId,
	int subPartitionIndex) throws IOException {

	synchronized (requestLock) {
		if (subpartitionView == null) {
			// This this call can trigger a notification we have to
			// schedule a separate task at the event loop that will
			// start consuming this. Otherwise the reference to the
			// view cannot be available in getNextBuffer().
			this.subpartitionView = partitionProvider.createSubpartitionView(
				resultPartitionId,
				subPartitionIndex,
				this);
		} else {
			throw new IllegalStateException("Subpartition already requested");
		}
	}
}
 

private void testBufferWriting(ResultSubpartitionView view) throws IOException {
	// setup
	ResultPartitionProvider partitionProvider =
		(partitionId, index, availabilityListener) -> view;

	final InputChannelID receiverId = new InputChannelID();
	final PartitionRequestQueue queue = new PartitionRequestQueue();
	final SequenceNumberingViewReader reader = new SequenceNumberingViewReader(receiverId, queue);
	final EmbeddedChannel channel = new EmbeddedChannel(queue);

	reader.requestSubpartitionView(partitionProvider, new ResultPartitionID(), 0);

	// notify about buffer availability and encode one buffer
	reader.notifyDataAvailable();

	channel.runPendingTasks();

	Object read = channel.readOutbound();
	assertNotNull(read);
	if (read instanceof NettyMessage.ErrorResponse) {
		((NettyMessage.ErrorResponse) read).cause.printStackTrace();
	}
	assertThat(read, instanceOf(NettyMessage.BufferResponse.class));
	read = channel.readOutbound();
	assertNull(read);
}
 

@Override
public void requestSubpartitionView(
	ResultPartitionProvider partitionProvider,
	ResultPartitionID resultPartitionId,
	int subPartitionIndex) throws IOException {

	synchronized (requestLock) {
		if (subpartitionView == null) {
			// This this call can trigger a notification we have to
			// schedule a separate task at the event loop that will
			// start consuming this. Otherwise the reference to the
			// view cannot be available in getNextBuffer().
			this.subpartitionView = partitionProvider.createSubpartitionView(
				resultPartitionId,
				subPartitionIndex,
				this);
		} else {
			throw new IllegalStateException("Subpartition already requested");
		}
	}
}
 

@Test
public void testProducerFailedException() throws Exception {
	PartitionRequestQueue queue = new PartitionRequestQueue();

	ResultSubpartitionView view = new ReleasedResultSubpartitionView();

	ResultPartitionProvider partitionProvider =
		(partitionId, index, availabilityListener) -> view;

	EmbeddedChannel ch = new EmbeddedChannel(queue);

	CreditBasedSequenceNumberingViewReader seqView = new CreditBasedSequenceNumberingViewReader(new InputChannelID(), 2, queue);
	seqView.requestSubpartitionView(partitionProvider, new ResultPartitionID(), 0);
	// Add available buffer to trigger enqueue the erroneous view
	seqView.notifyDataAvailable();

	ch.runPendingTasks();

	// Read the enqueued msg
	Object msg = ch.readOutbound();

	assertEquals(msg.getClass(), NettyMessage.ErrorResponse.class);

	NettyMessage.ErrorResponse err = (NettyMessage.ErrorResponse) msg;
	assertTrue(err.cause instanceof CancelTaskException);
}
 

@Test
public void testProducerFailedException() throws Exception {
	PartitionRequestQueue queue = new PartitionRequestQueue();

	ResultSubpartitionView view = new ReleasedResultSubpartitionView();

	ResultPartitionProvider partitionProvider =
		(partitionId, index, availabilityListener) -> view;

	EmbeddedChannel ch = new EmbeddedChannel(queue);

	CreditBasedSequenceNumberingViewReader seqView = new CreditBasedSequenceNumberingViewReader(new InputChannelID(), 2, queue);
	seqView.requestSubpartitionView(partitionProvider, new ResultPartitionID(), 0);
	// Add available buffer to trigger enqueue the erroneous view
	seqView.notifyDataAvailable();

	ch.runPendingTasks();

	// Read the enqueued msg
	Object msg = ch.readOutbound();

	assertEquals(msg.getClass(), NettyMessage.ErrorResponse.class);

	NettyMessage.ErrorResponse err = (NettyMessage.ErrorResponse) msg;
	assertTrue(err.cause instanceof CancelTaskException);
}
 

@Override
public void requestSubpartitionView(
	ResultPartitionProvider partitionProvider,
	ResultPartitionID resultPartitionId,
	int subPartitionIndex) throws IOException {

	synchronized (requestLock) {
		if (subpartitionView == null) {
			// This this call can trigger a notification we have to
			// schedule a separate task at the event loop that will
			// start consuming this. Otherwise the reference to the
			// view cannot be available in getNextBuffer().
			this.subpartitionView = partitionProvider.createSubpartitionView(
				resultPartitionId,
				subPartitionIndex,
				this);
		} else {
			throw new IllegalStateException("Subpartition already requested");
		}
	}
}
 

@Override
public void requestSubpartitionView(
	ResultPartitionProvider partitionProvider,
	ResultPartitionID resultPartitionId,
	int subPartitionIndex) throws IOException {

	synchronized (requestLock) {
		if (subpartitionView == null) {
			// This this call can trigger a notification we have to
			// schedule a separate task at the event loop that will
			// start consuming this. Otherwise the reference to the
			// view cannot be available in getNextBuffer().
			this.subpartitionView = partitionProvider.createSubpartitionView(
				resultPartitionId,
				subPartitionIndex,
				this);
		} else {
			throw new IllegalStateException("Subpartition already requested");
		}
	}
}
 

private void testBufferWriting(ResultSubpartitionView view) throws IOException {
	// setup
	ResultPartitionProvider partitionProvider =
		(partitionId, index, availabilityListener) -> view;

	final InputChannelID receiverId = new InputChannelID();
	final PartitionRequestQueue queue = new PartitionRequestQueue();
	final CreditBasedSequenceNumberingViewReader reader = new CreditBasedSequenceNumberingViewReader(
		receiverId,
		Integer.MAX_VALUE,
		queue);
	final EmbeddedChannel channel = new EmbeddedChannel(queue);

	reader.requestSubpartitionView(partitionProvider, new ResultPartitionID(), 0);

	// notify about buffer availability and encode one buffer
	reader.notifyDataAvailable();

	channel.runPendingTasks();

	Object read = channel.readOutbound();
	assertNotNull(read);
	if (read instanceof NettyMessage.ErrorResponse) {
		((NettyMessage.ErrorResponse) read).cause.printStackTrace();
	}
	assertThat(read, instanceOf(NettyMessage.BufferResponse.class));
	read = channel.readOutbound();
	assertNull(read);
}
 

@Override
public void start(ResultPartitionProvider partitionProvider, TaskEventDispatcher taskEventDispatcher) throws IOException {
	NettyProtocol partitionRequestProtocol = new NettyProtocol(
		partitionProvider,
		taskEventDispatcher,
		client.getConfig().isCreditBasedEnabled());

	client.init(partitionRequestProtocol, bufferPool);
	server.init(partitionRequestProtocol, bufferPool);
}
 

/**
 * Tests {@link PartitionRequestQueue#enqueueAvailableReader(NetworkSequenceViewReader)},
 * verifying the reader would be enqueued in the pipeline if the next sending buffer is an event
 * even though it has no available credits.
 */
@Test
public void testEnqueueReaderByNotifyingEventBuffer() throws Exception {
	// setup
	final ResultSubpartitionView view = new NextIsEventResultSubpartitionView();

	ResultPartitionProvider partitionProvider =
		(partitionId, index, availabilityListener) -> view;

	final InputChannelID receiverId = new InputChannelID();
	final PartitionRequestQueue queue = new PartitionRequestQueue();
	final CreditBasedSequenceNumberingViewReader reader = new CreditBasedSequenceNumberingViewReader(receiverId, 0, queue);
	final EmbeddedChannel channel = new EmbeddedChannel(queue);

	reader.requestSubpartitionView(partitionProvider, new ResultPartitionID(), 0);

	// block the channel so that we see an intermediate state in the test
	ByteBuf channelBlockingBuffer = blockChannel(channel);
	assertNull(channel.readOutbound());

	// Notify an available event buffer to trigger enqueue the reader
	reader.notifyDataAvailable();

	channel.runPendingTasks();

	// The reader is enqueued in the pipeline because the next buffer is an event, even though no credits are available
	assertThat(queue.getAvailableReaders(), contains(reader)); // contains only (this) one!
	assertEquals(0, reader.getNumCreditsAvailable());

	// Flush the buffer to make the channel writable again and see the final results
	channel.flush();
	assertSame(channelBlockingBuffer, channel.readOutbound());

	assertEquals(0, queue.getAvailableReaders().size());
	assertEquals(0, reader.getNumCreditsAvailable());
	assertNull(channel.readOutbound());
}
 

PartitionRequestServerHandler(
	ResultPartitionProvider partitionProvider,
	TaskEventPublisher taskEventPublisher,
	PartitionRequestQueue outboundQueue) {

	this.partitionProvider = partitionProvider;
	this.taskEventPublisher = taskEventPublisher;
	this.outboundQueue = outboundQueue;
}
 

public NettyConnectionManager(
	ResultPartitionProvider partitionProvider,
	TaskEventPublisher taskEventPublisher,
	NettyConfig nettyConfig) {

	this.server = new NettyServer(nettyConfig);
	this.client = new NettyClient(nettyConfig);
	this.bufferPool = new NettyBufferPool(nettyConfig.getNumberOfArenas());

	this.partitionRequestClientFactory = new PartitionRequestClientFactory(client);

	this.nettyProtocol = new NettyProtocol(checkNotNull(partitionProvider), checkNotNull(taskEventPublisher));
}
 

private EmbeddedChannel createEmbeddedChannel() {
	NettyProtocol protocol = new NettyProtocol(
			mock(ResultPartitionProvider.class),
			mock(TaskEventDispatcher.class),
			true);

	return new EmbeddedChannel(protocol.getClientChannelHandlers());
}
 

/**
 * Tests {@link PartitionRequestQueue#enqueueAvailableReader(NetworkSequenceViewReader)},
 * verifying the reader would be enqueued in the pipeline if the next sending buffer is an event
 * even though it has no available credits.
 */
@Test
public void testEnqueueReaderByNotifyingEventBuffer() throws Exception {
	// setup
	final ResultSubpartitionView view = new NextIsEventResultSubpartitionView();

	ResultPartitionProvider partitionProvider =
		(partitionId, index, availabilityListener) -> view;

	final InputChannelID receiverId = new InputChannelID();
	final PartitionRequestQueue queue = new PartitionRequestQueue();
	final CreditBasedSequenceNumberingViewReader reader = new CreditBasedSequenceNumberingViewReader(receiverId, 0, queue);
	final EmbeddedChannel channel = new EmbeddedChannel(queue);

	reader.requestSubpartitionView(partitionProvider, new ResultPartitionID(), 0);

	// block the channel so that we see an intermediate state in the test
	ByteBuf channelBlockingBuffer = blockChannel(channel);
	assertNull(channel.readOutbound());

	// Notify an available event buffer to trigger enqueue the reader
	reader.notifyDataAvailable();

	channel.runPendingTasks();

	// The reader is enqueued in the pipeline because the next buffer is an event, even though no credits are available
	assertThat(queue.getAvailableReaders(), contains(reader)); // contains only (this) one!
	assertEquals(0, reader.getNumCreditsAvailable());

	// Flush the buffer to make the channel writable again and see the final results
	channel.flush();
	assertSame(channelBlockingBuffer, channel.readOutbound());

	assertEquals(0, queue.getAvailableReaders().size());
	assertEquals(0, reader.getNumCreditsAvailable());
	assertNull(channel.readOutbound());
}
 

/**
 * Tests {@link PartitionRequestQueue#enqueueAvailableReader(NetworkSequenceViewReader)},
 * verifying the reader would be enqueued in the pipeline after resuming data consumption if there
 * are credit and data available.
 */
@Test
public void testEnqueueReaderByResumingConsumption() throws Exception {
	PipelinedSubpartition subpartition = PipelinedSubpartitionTest.createPipelinedSubpartition();
	Buffer.DataType dataType1 = Buffer.DataType.ALIGNED_EXACTLY_ONCE_CHECKPOINT_BARRIER;
	Buffer.DataType dataType2 = Buffer.DataType.DATA_BUFFER;
	subpartition.add(createEventBufferConsumer(4096, dataType1));
	subpartition.add(createEventBufferConsumer(4096, dataType2));

	BufferAvailabilityListener bufferAvailabilityListener = new NoOpBufferAvailablityListener();
	PipelinedSubpartitionView view = subpartition.createReadView(bufferAvailabilityListener);
	ResultPartitionProvider partitionProvider = (partitionId, index, availabilityListener) -> view;

	InputChannelID receiverId = new InputChannelID();
	PartitionRequestQueue queue = new PartitionRequestQueue();
	CreditBasedSequenceNumberingViewReader reader = new CreditBasedSequenceNumberingViewReader(receiverId, 0, queue);
	EmbeddedChannel channel = new EmbeddedChannel(queue);

	reader.requestSubpartitionView(partitionProvider, new ResultPartitionID(), 0);
	queue.notifyReaderCreated(reader);
	// we have adequate credits
	reader.addCredit(Integer.MAX_VALUE);
	assertTrue(reader.isAvailable());

	reader.notifyDataAvailable();
	channel.runPendingTasks();
	assertFalse(reader.isAvailable());
	assertEquals(1, subpartition.unsynchronizedGetNumberOfQueuedBuffers());

	queue.addCreditOrResumeConsumption(receiverId, NetworkSequenceViewReader::resumeConsumption);
	assertFalse(reader.isAvailable());
	assertEquals(0, subpartition.unsynchronizedGetNumberOfQueuedBuffers());

	Object data1 = channel.readOutbound();
	assertEquals(dataType1, ((NettyMessage.BufferResponse) data1).buffer.getDataType());
	Object data2 = channel.readOutbound();
	assertEquals(dataType2, ((NettyMessage.BufferResponse) data2).buffer.getDataType());
}
 

private EmbeddedChannel createEmbeddedChannel() {
	NettyProtocol protocol = new NettyProtocol(
			mock(ResultPartitionProvider.class),
			mock(TaskEventDispatcher.class));

	return new EmbeddedChannel(protocol.getClientChannelHandlers());
}
 

PartitionRequestServerHandler(
	ResultPartitionProvider partitionProvider,
	TaskEventPublisher taskEventPublisher,
	PartitionRequestQueue outboundQueue,
	boolean creditBasedEnabled) {

	this.partitionProvider = partitionProvider;
	this.taskEventPublisher = taskEventPublisher;
	this.outboundQueue = outboundQueue;
	this.creditBasedEnabled = creditBasedEnabled;
}
 

public NettyConnectionManager(
	ResultPartitionProvider partitionProvider,
	TaskEventPublisher taskEventPublisher,
	NettyConfig nettyConfig,
	boolean isCreditBased) {

	this.server = new NettyServer(nettyConfig);
	this.client = new NettyClient(nettyConfig);
	this.bufferPool = new NettyBufferPool(nettyConfig.getNumberOfArenas());

	this.partitionRequestClientFactory = new PartitionRequestClientFactory(client);

	this.nettyProtocol = new NettyProtocol(checkNotNull(partitionProvider), checkNotNull(taskEventPublisher), isCreditBased);
}
 

PartitionRequestServerHandler(
	ResultPartitionProvider partitionProvider,
	TaskEventDispatcher taskEventDispatcher,
	PartitionRequestQueue outboundQueue,
	boolean creditBasedEnabled) {

	this.partitionProvider = partitionProvider;
	this.taskEventDispatcher = taskEventDispatcher;
	this.outboundQueue = outboundQueue;
	this.creditBasedEnabled = creditBasedEnabled;
}
 

private EmbeddedChannel createEmbeddedChannel() {
	NettyProtocol protocol = new NettyProtocol(
			mock(ResultPartitionProvider.class),
			mock(TaskEventDispatcher.class),
			true);

	return new EmbeddedChannel(protocol.getClientChannelHandlers());
}
 

/**
 * Tests {@link PartitionRequestQueue#enqueueAvailableReader(NetworkSequenceViewReader)},
 * verifying the reader would be enqueued in the pipeline if the next sending buffer is an event
 * even though it has no available credits.
 */
@Test
public void testEnqueueReaderByNotifyingEventBuffer() throws Exception {
	// setup
	final ResultSubpartitionView view = new NextIsEventResultSubpartitionView();

	ResultPartitionProvider partitionProvider =
		(partitionId, index, availabilityListener) -> view;

	final InputChannelID receiverId = new InputChannelID();
	final PartitionRequestQueue queue = new PartitionRequestQueue();
	final CreditBasedSequenceNumberingViewReader reader = new CreditBasedSequenceNumberingViewReader(receiverId, 0, queue);
	final EmbeddedChannel channel = new EmbeddedChannel(queue);

	reader.requestSubpartitionView(partitionProvider, new ResultPartitionID(), 0);

	// block the channel so that we see an intermediate state in the test
	ByteBuf channelBlockingBuffer = blockChannel(channel);
	assertNull(channel.readOutbound());

	// Notify an available event buffer to trigger enqueue the reader
	reader.notifyDataAvailable();

	channel.runPendingTasks();

	// The reader is enqueued in the pipeline because the next buffer is an event, even though no credits are available
	assertThat(queue.getAvailableReaders(), contains(reader)); // contains only (this) one!
	assertEquals(0, reader.getNumCreditsAvailable());

	// Flush the buffer to make the channel writable again and see the final results
	channel.flush();
	assertSame(channelBlockingBuffer, channel.readOutbound());

	assertEquals(0, queue.getAvailableReaders().size());
	assertEquals(0, reader.getNumCreditsAvailable());
	assertNull(channel.readOutbound());
}
 

void start(ResultPartitionProvider partitionProvider,
TaskEventDispatcher taskEventDispatcher) throws IOException;
 

void requestSubpartitionView(
ResultPartitionProvider partitionProvider,
ResultPartitionID resultPartitionId,
int subPartitionIndex) throws IOException;
 

/**
 * Verifies that failed client requests via {@link PartitionRequestClient} are correctly
 * attributed to the respective {@link RemoteInputChannel}.
 */
@Test
public void testExceptionOnWrite() throws Exception {

	NettyProtocol protocol = new NettyProtocol(
			mock(ResultPartitionProvider.class),
			mock(TaskEventDispatcher.class)) {

		@Override
		public ChannelHandler[] getServerChannelHandlers() {
			return new ChannelHandler[0];
		}
	};

	// We need a real server and client in this test, because Netty's EmbeddedChannel is
	// not failing the ChannelPromise of failed writes.
	NettyServerAndClient serverAndClient = initServerAndClient(protocol, createConfig());

	Channel ch = connect(serverAndClient);

	NetworkClientHandler handler = getClientHandler(ch);

	// Last outbound handler throws Exception after 1st write
	ch.pipeline().addFirst(new ChannelOutboundHandlerAdapter() {
		int writeNum = 0;

		@Override
		public void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise)
				throws Exception {

			if (writeNum >= 1) {
				throw new RuntimeException("Expected test exception.");
			}

			writeNum++;
			ctx.write(msg, promise);
		}
	});

	PartitionRequestClient requestClient = new NettyPartitionRequestClient(
			ch, handler, mock(ConnectionID.class), mock(PartitionRequestClientFactory.class));

	// Create input channels
	RemoteInputChannel[] rich = new RemoteInputChannel[] {
			createRemoteInputChannel(), createRemoteInputChannel()};

	final CountDownLatch sync = new CountDownLatch(1);

	// Do this with explicit synchronization. Otherwise this is not robust against slow timings
	// of the callback (e.g. we cannot just verify that it was called once, because there is
	// a chance that we do this too early).
	doAnswer(new Answer<Void>() {
		@Override
		public Void answer(InvocationOnMock invocation) throws Throwable {
			sync.countDown();
			return null;
		}
	}).when(rich[1]).onError(isA(LocalTransportException.class));

	// First request is successful
	requestClient.requestSubpartition(new ResultPartitionID(), 0, rich[0], 0);

	// Second request is *not* successful
	requestClient.requestSubpartition(new ResultPartitionID(), 0, rich[1], 0);

	// Wait for the notification and it could confirm all the request operations are done
	if (!sync.await(TestingUtils.TESTING_DURATION().toMillis(), TimeUnit.MILLISECONDS)) {
		fail("Timed out after waiting for " + TestingUtils.TESTING_DURATION().toMillis() +
				" ms to be notified about the channel error.");
	}

	// Only the second channel should be notified about the error
	verify(rich[0], times(0)).onError(any(LocalTransportException.class));

	shutdown(serverAndClient);
}
 

/**
 * Tests {@link PartitionRequestQueue#enqueueAvailableReader(NetworkSequenceViewReader)},
 * verifying the reader would be enqueued in the pipeline iff it has both available credits and buffers.
 */
@Test
public void testEnqueueReaderByNotifyingBufferAndCredit() throws Exception {
	// setup
	final ResultSubpartitionView view = new DefaultBufferResultSubpartitionView(10);

	ResultPartitionProvider partitionProvider =
		(partitionId, index, availabilityListener) -> view;

	final InputChannelID receiverId = new InputChannelID();
	final PartitionRequestQueue queue = new PartitionRequestQueue();
	final CreditBasedSequenceNumberingViewReader reader = new CreditBasedSequenceNumberingViewReader(receiverId, 0, queue);
	final EmbeddedChannel channel = new EmbeddedChannel(queue);

	reader.requestSubpartitionView(partitionProvider, new ResultPartitionID(), 0);
	queue.notifyReaderCreated(reader);

	// block the channel so that we see an intermediate state in the test
	ByteBuf channelBlockingBuffer = blockChannel(channel);
	assertNull(channel.readOutbound());

	// Notify available buffers to trigger enqueue the reader
	final int notifyNumBuffers = 5;
	for (int i = 0; i < notifyNumBuffers; i++) {
		reader.notifyDataAvailable();
	}

	channel.runPendingTasks();

	// the reader is not enqueued in the pipeline because no credits are available
	// -> it should still have the same number of pending buffers
	assertEquals(0, queue.getAvailableReaders().size());
	assertTrue(reader.hasBuffersAvailable());
	assertFalse(reader.isRegisteredAsAvailable());
	assertEquals(0, reader.getNumCreditsAvailable());

	// Notify available credits to trigger enqueue the reader again
	final int notifyNumCredits = 3;
	for (int i = 1; i <= notifyNumCredits; i++) {
		queue.addCreditOrResumeConsumption(receiverId, viewReader -> viewReader.addCredit(1));

		// the reader is enqueued in the pipeline because it has both available buffers and credits
		// since the channel is blocked though, we will not process anything and only enqueue the
		// reader once
		assertTrue(reader.isRegisteredAsAvailable());
		assertThat(queue.getAvailableReaders(), contains(reader)); // contains only (this) one!
		assertEquals(i, reader.getNumCreditsAvailable());
		assertTrue(reader.hasBuffersAvailable());
	}

	// Flush the buffer to make the channel writable again and see the final results
	channel.flush();
	assertSame(channelBlockingBuffer, channel.readOutbound());

	assertEquals(0, queue.getAvailableReaders().size());
	assertEquals(0, reader.getNumCreditsAvailable());
	assertTrue(reader.hasBuffersAvailable());
	assertFalse(reader.isRegisteredAsAvailable());
	for (int i = 1; i <= notifyNumCredits; i++) {
		assertThat(channel.readOutbound(), instanceOf(NettyMessage.BufferResponse.class));
	}
	assertNull(channel.readOutbound());
}
 

NettyProtocol(ResultPartitionProvider partitionProvider, TaskEventDispatcher taskEventDispatcher, boolean creditBasedEnabled) {
	this.partitionProvider = partitionProvider;
	this.taskEventDispatcher = taskEventDispatcher;
	this.creditBasedEnabled = creditBasedEnabled;
}
 

void requestSubpartitionView(
ResultPartitionProvider partitionProvider,
ResultPartitionID resultPartitionId,
int subPartitionIndex) throws IOException;