[FLINK-3918] Not configuring any time characteristic leads to a ClassCastException

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.0.3
• Fix Version/s: 1.2.0
• Component/s: API / DataStream
• Assignee: Aljoscha Krettek
• Reporter: Robert Metzger
• Created: 17/May/16 10:13
• Updated: 30/Jan/17 10:18
• Resolved: 30/Jan/17 10:18

Description

When using any timestamp extractor related code in a streaming job, without setting the time characteristic, the RecordWriter will throw a ClassCastException.

This is not very intuitive for our users and we should report a more helpful exception there.

Output:

Exception in thread "main" org.apache.flink.runtime.client.JobExecutionException: Job execution failed.
	at org.apache.flink.runtime.jobmanager.JobManager$$anonfun$handleMessage$1$$anonfun$applyOrElse$7.apply$mcV$sp(JobManager.scala:717)
	at org.apache.flink.runtime.jobmanager.JobManager$$anonfun$handleMessage$1$$anonfun$applyOrElse$7.apply(JobManager.scala:663)
	at org.apache.flink.runtime.jobmanager.JobManager$$anonfun$handleMessage$1$$anonfun$applyOrElse$7.apply(JobManager.scala:663)
	at scala.concurrent.impl.Future$PromiseCompletingRunnable.liftedTree1$1(Future.scala:24)
	at scala.concurrent.impl.Future$PromiseCompletingRunnable.run(Future.scala:24)
	at akka.dispatch.TaskInvocation.run(AbstractDispatcher.scala:41)
	at akka.dispatch.ForkJoinExecutorConfigurator$AkkaForkJoinTask.exec(AbstractDispatcher.scala:401)
	at scala.concurrent.forkjoin.ForkJoinTask.doExec(ForkJoinTask.java:260)
	at scala.concurrent.forkjoin.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1339)
	at scala.concurrent.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979)
	at scala.concurrent.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107)
Caused by: java.lang.RuntimeException: Could not forward element to next operator
	at org.apache.flink.streaming.runtime.tasks.OperatorChain$CopyingChainingOutput.collect(OperatorChain.java:354)
	at org.apache.flink.streaming.runtime.tasks.OperatorChain$CopyingChainingOutput.collect(OperatorChain.java:337)
	at org.apache.flink.streaming.api.operators.StreamSource$NonTimestampContext.collect(StreamSource.java:158)
	at com.dataartisans.SocketTextStreamWordCount$DataGen.run(SocketTextStreamWordCount.java:98)
	at org.apache.flink.streaming.api.operators.StreamSource.run(StreamSource.java:78)
	at org.apache.flink.streaming.runtime.tasks.SourceStreamTask.run(SourceStreamTask.java:56)
	at org.apache.flink.streaming.runtime.tasks.StreamTask.invoke(StreamTask.java:225)
	at org.apache.flink.runtime.taskmanager.Task.run(Task.java:559)
	at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.RuntimeException: org.apache.flink.streaming.api.watermark.Watermark cannot be cast to org.apache.flink.streaming.runtime.streamrecord.StreamRecord
	at org.apache.flink.streaming.runtime.io.RecordWriterOutput.emitWatermark(RecordWriterOutput.java:93)
	at org.apache.flink.streaming.runtime.operators.TimestampsAndPunctuatedWatermarksOperator.processElement(TimestampsAndPunctuatedWatermarksOperator.java:58)
	at org.apache.flink.streaming.runtime.tasks.OperatorChain$CopyingChainingOutput.collect(OperatorChain.java:351)
	... 8 more
Caused by: java.lang.ClassCastException: org.apache.flink.streaming.api.watermark.Watermark cannot be cast to org.apache.flink.streaming.runtime.streamrecord.StreamRecord
	at org.apache.flink.streaming.runtime.streamrecord.StreamRecordSerializer.serialize(StreamRecordSerializer.java:42)
	at org.apache.flink.runtime.plugable.SerializationDelegate.write(SerializationDelegate.java:56)
	at org.apache.flink.runtime.io.network.api.serialization.SpanningRecordSerializer.addRecord(SpanningRecordSerializer.java:79)
	at org.apache.flink.runtime.io.network.api.writer.RecordWriter.broadcastEmit(RecordWriter.java:109)
	at org.apache.flink.streaming.runtime.io.StreamRecordWriter.broadcastEmit(StreamRecordWriter.java:95)
	at org.apache.flink.streaming.runtime.io.RecordWriterOutput.emitWatermark(RecordWriterOutput.java:90)
	... 10 more