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apache-flinkflink-streaming

flink checkpoint stuck on subtask with 0 bytes received

One of the subtasks doesn't have any input(i.e. bytes received are 0), and checkpoint of this subtask is stuck.

Is it normal, or is it a bug?

The flink version is 1.6.2.

Add more information.
Below is the topology. enter image description here

And the third task(i.e. 'Window(TumblingProcessingTimeWindows(30000), ProcessingTimeTrigger, ScalaReduceFunction, PassThroughWindowFunction) -> Map -> Sink: Unnamed') has five subtasks whose 'Bytes received' is 0. And checkpoint stuck on these five subtasks. One of the subtasks is shown as below. enter image description here

And every time I restart the application, 'Bytes received 0' happens on different number of subtasks.

Why?

Solution

  • Flink 1.6.2 had some bugs related to checkpointing. Can you upgrade to 1.6.4, perhaps, and see if that resolves the issue?