Re: Help me understand this Exception

Posted by Tzu-Li (Gordon) Tai on
URL: http://deprecated-apache-flink-user-mailing-list-archive.369.s1.nabble.com/Help-me-understand-this-Exception-tp33733p33734.html

Hi,

The exception stack you posted simply means that the next operator in the chain failed to process the output watermark.
There should be another exception, which would explain why some operator was closed / failed and eventually leading to the above exception.
That would provide more insight to exactly why your job is failing.

Cheers,
Gordon

On Tue, Mar 17, 2020 at 11:27 PM aj <[hidden email]> wrote:

Hi,

I am running a streaming job with generating watermark like this :

public static class SessionAssigner implements AssignerWithPunctuatedWatermarks<GenericRecord> {
    @Override
    public long extractTimestamp(GenericRecord record, long previousElementTimestamp) {
        long timestamp = (long) record.get("event_ts");
        LOGGER.info("timestamp----", timestamp);
        return timestamp;
    }

    @Override
    public Watermark checkAndGetNextWatermark(GenericRecord record, long extractedTimestamp) {
        // simply emit a watermark with every event
        LOGGER.info("extractedTimestamp ", extractedTimestamp);
        return new Watermark(extractedTimestamp);
    }
}

Please help me understand what this exception means:

java.lang.RuntimeException: Exception occurred while processing valve output watermark:

    at org.apache.flink.streaming.runtime.io.StreamOneInputProcessor$ForwardingValveOutputHandler.handleWatermark(StreamOneInputProcessor.java:216)

    at org.apache.flink.streaming.runtime.streamstatus.StatusWatermarkValve.findAndOutputNewMinWatermarkAcrossAlignedChannels(StatusWatermarkValve.java:189)

    at org.apache.flink.streaming.runtime.streamstatus.StatusWatermarkValve.inputWatermark(StatusWatermarkValve.java:111)

    at org.apache.flink.streaming.runtime.io.StreamOneInputProcessor.processElement(StreamOneInputProcessor.java:169)

    at org.apache.flink.streaming.runtime.io.StreamOneInputProcessor.processInput(StreamOneInputProcessor.java:143)

    at org.apache.flink.streaming.runtime.tasks.StreamTask.processInput(StreamTask.java:279)

    at org.apache.flink.streaming.runtime.tasks.StreamTask.run(StreamTask.java:301)

    at org.apache.flink.streaming.runtime.tasks.StreamTask.invoke(StreamTask.java:406)

    at org.apache.flink.runtime.taskmanager.Task.doRun(Task.java:705)

    at org.apache.flink.runtime.taskmanager.Task.run(Task.java:530)

    at java.lang.Thread.run(Thread.java:748)

Caused by: org.apache.flink.streaming.runtime.tasks.ExceptionInChainedOperatorException: Could not forward element to next operator

    at org.apache.flink.streaming.runtime.tasks.OperatorChain$CopyingChainingOutput.pushToOperator(OperatorChain.java:654)

    at org.apache.flink.streaming.runtime.tasks.OperatorChain$CopyingChainingOutput.collect(OperatorChain.java:612)

    at org.apache.flink.streaming.runtime.tasks.OperatorChain$CopyingChainingOutput.collect(OperatorChain.java:592)

    at org.apache.flink.streaming.runtime.tasks.OperatorChain$BroadcastingOutputCollector.collect(OperatorChain.java:707)

    at org.apache.flink.streaming.runtime.tasks.OperatorChain$BroadcastingOutputCollector.collect(OperatorChain.java:660)

    at org.apache.flink.streaming.api.operators.AbstractStreamOperator$CountingOutput.collect(AbstractStreamOperator.java:727)

    at org.apache.flink.streaming.api.operators.AbstractStreamOperator$CountingOutput.collect(AbstractStreamOperator.java:705)

    at org.apache.flink.streaming.api.operators.TimestampedCollector.collect(TimestampedCollector.java:51)

    at com.bounce.test.SessionProcessor$2.process(SessionProcessor.java:137)

    at com.bounce.test.SessionProcessor$2.process(SessionProcessor.java:116)

    at org.apache.flink.streaming.runtime.operators.windowing.functions.InternalIterableProcessWindowFunction.process(InternalIterableProcessWindowFunction.java:50)

    at org.apache.flink.streaming.runtime.operators.windowing.functions.InternalIterableProcessWindowFunction.process(InternalIterableProcessWindowFunction.java:32)

    at org.apache.flink.streaming.runtime.operators.windowing.WindowOperator.emitWindowContents(WindowOperator.java:549)

    at org.apache.flink.streaming.runtime.operators.windowing.WindowOperator.onEventTime(WindowOperator.java:457)

    at org.apache.flink.streaming.api.operators.InternalTimerServiceImpl.advanceWatermark(InternalTimerServiceImpl.java:276)

    at org.apache.flink.streaming.api.operators.InternalTimeServiceManager.advanceWatermark(InternalTimeServiceManager.java:128)

    at org.apache.flink.streaming.api.operators.AbstractStreamOperator.processWatermark(AbstractStreamOperator.java:784)

    at org.apache.flink.streaming.runtime.io.StreamOneInputProcessor$ForwardingValveOutputHandler.handleWatermark(StreamOneInputProcessor.java:213)

    ... 10 more

--

Thanks & Regards,
Anuj Jain