Hi. I am using 2.10.4 for Scala. 1.6.0 for Spark related dependencies. I am
also using spark-streaming-kafka and including kafka (0.8.1.1) which apparently
is needed for deserializers.
> On Apr 4, 2016, at 6:18 PM, Ted Yu <yuzhih...@gmail.com> wrote:
>
> bq. I'm on version 2.10 for spark
>
> The above is Scala version.
> Can you give us the Spark version ?
>
> Thanks
>
>> On Mon, Apr 4, 2016 at 2:36 PM, mpawashe <mpawa...@gmail.com> wrote:
>> Hi all,
>>
>> I am using Spark Streaming API (I'm on version 2.10 for spark and
>> streaming), and I am running into a function serialization issue that I do
>> not run into when using Spark in batch (non-streaming) mode.
>>
>> If I wrote code like this:
>>
>> def run(): Unit = {
>> val newStream = stream.map(x => { x + " foo " })
>> // ...
>> }
>>
>> everything works fine.. But if I try it like this:
>>
>> def transform(x: String): String = { x + " foo " }
>>
>> def run(): Unit = {
>> val newStream = stream.map(transform)
>> // ...
>> }
>>
>> ..the program fails being unable to serialize the closure (which when
>> passing a method to a function that expects a closure, it should be
>> auto-converted to my understanding).
>>
>> However it works fine if I declare a closure inside run() and use that like
>> so:
>>
>> val transform = (x: String) => { x + " foo " }
>>
>> If it's declared outside of run(), however, it will also crash.
>>
>> This is an example stack trace of the error I'm running into. This can be a
>> hassle to debug so I hope I wouldn't have to get around this by having to
>> use a local closure/function every time. Thanks for any help in advance.
>>
>> org.apache.spark.SparkException: Task not serializable
>> at
>> org.apache.spark.util.ClosureCleaner$.ensureSerializable(ClosureCleaner.scala:304)
>> at
>> org.apache.spark.util.ClosureCleaner$.org$apache$spark$util$ClosureCleaner$$clean(ClosureCleaner.scala:294)
>> at
>> org.apache.spark.util.ClosureCleaner$.clean(ClosureCleaner.scala:122)
>> at org.apache.spark.SparkContext.clean(SparkContext.scala:2030)
>> at
>> org.apache.spark.streaming.dstream.DStream$$anonfun$map$1.apply(DStream.scala:528)
>> at
>> org.apache.spark.streaming.dstream.DStream$$anonfun$map$1.apply(DStream.scala:528)
>> at
>> org.apache.spark.rdd.RDDOperationScope$.withScope(RDDOperationScope.scala:147)
>> at
>> org.apache.spark.rdd.RDDOperationScope$.withScope(RDDOperationScope.scala:108)
>> at org.apache.spark.SparkContext.withScope(SparkContext.scala:709)
>> at
>> org.apache.spark.streaming.StreamingContext.withScope(StreamingContext.scala:266)
>> at org.apache.spark.streaming.dstream.DStream.map(DStream.scala:527)
>> at com.my.cool.app.MyClass.run(MyClass.scala:90)
>> at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
>> at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
>> at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
>> at java.lang.reflect.Method.invoke(Unknown Source)
>> at
>> org.apache.spark.deploy.worker.DriverWrapper$.main(DriverWrapper.scala:58)
>> at
>> org.apache.spark.deploy.worker.DriverWrapper.main(DriverWrapper.scala)
>> Caused by: java.io.NotSerializableException: Graph is unexpectedly null when
>> DStream is being serialized.
>> Serialization stack:
>>
>> at
>> org.apache.spark.serializer.SerializationDebugger$.improveException(SerializationDebugger.scala:40)
>> at
>> org.apache.spark.serializer.JavaSerializationStream.writeObject(JavaSerializer.scala:47)
>> at
>> org.apache.spark.serializer.JavaSerializerInstance.serialize(JavaSerializer.scala:84)
>> at
>> org.apache.spark.util.ClosureCleaner$.ensureSerializable(ClosureCleaner.scala:301)
>> ... 20 more
>>
>>
>>
>> --
>> View this message in context:
>> http://apache-spark-user-list.1001560.n3.nabble.com/Spark-Streaming-NotSerializableException-Methods-Closures-tp26672.html
>> Sent from the Apache Spark User List mailing list archive at Nabble.com.
>>
>> ---------------------------------------------------------------------
>> To unsubscribe, e-mail: user-unsubscr...@spark.apache.org
>> For additional commands, e-mail: user-h...@spark.apache.org
>
