Github user zhijiangW commented on a diff in the pull request: https://github.com/apache/flink/pull/4533#discussion_r143671614 --- Diff: flink-runtime/src/main/java/org/apache/flink/runtime/io/network/netty/CreditBasedClientHandler.java --- @@ -37,20 +43,31 @@ import java.io.IOException; import java.net.SocketAddress; +import java.util.ArrayDeque; import java.util.concurrent.ConcurrentHashMap; import java.util.concurrent.ConcurrentMap; import java.util.concurrent.atomic.AtomicReference; +/** + * Channel handler to read {@link BufferResponse} and {@link ErrorResponse} messages from the + * producer, to write and flush {@link AddCredit} message for the producer. + */ class CreditBasedClientHandler extends ChannelInboundHandlerAdapter { private static final Logger LOG = LoggerFactory.getLogger(CreditBasedClientHandler.class); + /** Channels, which already requested partitions from the producers. */ private final ConcurrentMap<InputChannelID, RemoteInputChannel> inputChannels = new ConcurrentHashMap<>(); + /** Channels, which will notify the producers about unannounced credit. */ + private final ArrayDeque<RemoteInputChannel> inputChannelsWithCredit = new ArrayDeque<>(); + private final AtomicReference<Throwable> channelError = new AtomicReference<>(); + private final ChannelFutureListener writeListener = new WriteAndFlushNextMessageIfPossibleListener(); + /** - * Set of cancelled partition requests. A request is cancelled iff an input channel is cleared + * Set of cancelled partition requests. A request is cancelled if an input channel is cleared --- End diff -- got it, already restored the original writing.
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