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From Till Rohrmann <trohrm...@apache.org>
Subject Re: ClassCastException when redeploying Flink job on running cluster
Date Wed, 08 Jun 2016 15:41:18 GMT
The only thing I could think of is to not use the SpecificData singleton
but instead creating a new SpecificData object for each SpecificDatumReader
(you can pass it as a third argument to the constructor). This, of course,
is not really efficient. But you could try it out to see whether it solves
your problem.

Cheers,
Till

On Wed, Jun 8, 2016 at 4:24 PM, Josh <jofo90@gmail.com> wrote:

> Sorry - I forgot to include my stack trace too. Here it is:
>
> The program finished with the following exception:
>
> org.apache.flink.client.program.ProgramInvocationException: The program
> execution failed: Job execution failed.
> at org.apache.flink.client.program.Client.runBlocking(Client.java:381)
> at org.apache.flink.client.program.Client.runBlocking(Client.java:355)
> at
> org.apache.flink.streaming.api.environment.StreamContextEnvironment.execute(StreamContextEnvironment.java:65)
> at
> org.apache.flink.streaming.api.scala.StreamExecutionEnvironment.execute(StreamExecutionEnvironment.scala:536)
> at com.me.flink.job.MyFlinkJob$.main(MyFlinkJob.scala:85)
> at com.me.flink.job.MyFlinkJob.main(MyFlinkJob.scala)
> at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
> at
> sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
> at
> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
> at java.lang.reflect.Method.invoke(Method.java:498)
> at
> org.apache.flink.client.program.PackagedProgram.callMainMethod(PackagedProgram.java:505)
> at
> org.apache.flink.client.program.PackagedProgram.invokeInteractiveModeForExecution(PackagedProgram.java:403)
> at org.apache.flink.client.program.Client.runBlocking(Client.java:248)
> at
> org.apache.flink.client.CliFrontend.executeProgramBlocking(CliFrontend.java:866)
> at org.apache.flink.client.CliFrontend.run(CliFrontend.java:333)
> at
> org.apache.flink.client.CliFrontend.parseParameters(CliFrontend.java:1192)
> at org.apache.flink.client.CliFrontend.main(CliFrontend.java:1243)
> Caused by: 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.pollAndExecAll(ForkJoinPool.java:1253)
> at
> scala.concurrent.forkjoin.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1346)
> at scala.concurrent.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979)
> at
> scala.concurrent.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107)
> Caused by: java.lang.Exception: Could not forward element to next operator
> at
> org.apache.flink.streaming.connectors.kinesis.internals.KinesisDataFetcher.run(KinesisDataFetcher.java:150)
> at
> org.apache.flink.streaming.connectors.kinesis.FlinkKinesisConsumer.run(FlinkKinesisConsumer.java:285)
> at
> org.apache.flink.streaming.api.operators.StreamSource.run(StreamSource.java:78)
> at
> org.apache.flink.streaming.runtime.tasks.SourceStreamTask.run(SourceStreamTask.java:56)
> at
> org.apache.flink.streaming.runtime.tasks.StreamTask.invoke(StreamTask.java:225)
> at org.apache.flink.runtime.taskmanager.Task.run(Task.java:559)
> at java.lang.Thread.run(Thread.java:745)
> Caused by: java.lang.RuntimeException: Could not forward element to next
> operator
> at
> org.apache.flink.streaming.runtime.tasks.OperatorChain$CopyingChainingOutput.collect(OperatorChain.java:354)
> at
> org.apache.flink.streaming.runtime.tasks.OperatorChain$CopyingChainingOutput.collect(OperatorChain.java:337)
> at
> org.apache.flink.streaming.api.operators.StreamSource$ManualWatermarkContext.collect(StreamSource.java:318)
> at
> org.apache.flink.streaming.connectors.kinesis.internals.ShardConsumerThread.run(ShardConsumerThread.java:141)
> Caused by: java.lang.ClassCastException: com.me.avro.MyAvroType cannot be
> cast to com.me.avro.MyAvroType
> at com.me.flink.job.MyFlinkJob$$anonfun$1.apply(MyFlinkJob.scala:61)
> at
> org.apache.flink.streaming.api.scala.DataStream$$anon$1.extractAscendingTimestamp(DataStream.scala:746)
> at
> org.apache.flink.streaming.api.functions.AscendingTimestampExtractor.extractTimestamp(AscendingTimestampExtractor.java:71)
> at
> org.apache.flink.streaming.runtime.operators.TimestampsAndPeriodicWatermarksOperator.processElement(TimestampsAndPeriodicWatermarksOperator.java:63)
> at
> org.apache.flink.streaming.runtime.tasks.OperatorChain$CopyingChainingOutput.collect(OperatorChain.java:351)
> ... 3 more
>
> On Wed, Jun 8, 2016 at 3:19 PM, Josh <jofo90@gmail.com> wrote:
>
>> Hi Till,
>>
>> Thanks for the reply! I see - yes it does sound very much like FLINK-1390.
>>
>> Please see my AvroDeserializationSchema implementation here:
>> http://pastebin.com/mK7SfBQ8
>>
>> I think perhaps the problem is caused by this line:
>> val readerSchema = SpecificData.get().getSchema(classTag[T].runtimeClass)
>>
>> Looking at SpecificData, it contains a classCache which is a map of
>> strings to classes, similar to what's described in FLINK-1390.
>>
>> I'm not sure how to change my AvroDeserializationSchema to prevent this
>> from happening though! Do you have any ideas?
>>
>> Josh
>>
>>
>>
>> On Wed, Jun 8, 2016 at 11:23 AM, Till Rohrmann <trohrmann@apache.org>
>> wrote:
>>
>>> Hi Josh,
>>>
>>> the error message you've posted usually indicates that there is a class
>>> loader issue. When you first run your program the class
>>> com.me.avro.MyAvroType will be first loaded (by the user code class
>>> loader). I suspect that this class is now somewhere cached (e.g. the avro
>>> serializer) and when you run your program a second time, then there is a
>>> new user code class loader which has loaded the same class and now you want
>>> to convert an instance of the first class into the second class. However,
>>> these two classes are not identical since they were loaded by different
>>> class loaders.
>>>
>>> In order to find the culprit, it would be helpful to see the full stack
>>> trace of the ClassCastException and the code of the
>>> AvroDeserializationSchema. I suspect that something similar to
>>> https://issues.apache.org/jira/browse/FLINK-1390 is happening.
>>>
>>> Cheers,
>>> Till
>>>
>>> On Wed, Jun 8, 2016 at 10:38 AM, Josh <jofo90@gmail.com> wrote:
>>>
>>>> Hi all,
>>>>
>>>> Currently I have to relaunch my Flink cluster every time I want to
>>>> upgrade/redeploy my Flink job, because otherwise I get a ClassCastException:
>>>>
>>>> java.lang.ClassCastException: com.me.avro.MyAvroType cannot be cast to
>>>> com.me.avro.MyAvroType
>>>>
>>>> It's related to MyAvroType which is an class generated from an Avro
>>>> schema. The ClassCastException occurs every time I redeploy the job without
>>>> killing the Flink cluster (even if there have been no changes to the
>>>> job/jar).
>>>>
>>>> I wrote my own AvroDeserializationSchema in Scala which does something
>>>> a little strange to get the avro type information (see below), and I'm
>>>> wondering if that's causing the problem when the Flink job creates an
>>>> AvroDeserializationSchema[MyAvroType].
>>>>
>>>> Does anyone have any ideas?
>>>>
>>>> Thanks,
>>>> Josh
>>>>
>>>>
>>>>
>>>> class AvroDeserializationSchema[T <: SpecificRecordBase :ClassTag]
>>>> extends DeserializationSchema[T] {
>>>>
>>>>   ...
>>>>
>>>>   private val avroType =
>>>> classTag[T].runtimeClass.asInstanceOf[Class[T]]
>>>>
>>>>   private val typeInformation = TypeExtractor.getForClass(avroType)
>>>>
>>>>   ...
>>>>
>>>>   override def getProducedType: TypeInformation[T] = typeInformation
>>>>
>>>>   ...
>>>>
>>>> }
>>>>
>>>
>>>
>>
>

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