Spark groupBy issue

Question

Trying write simple program with spqrk. I have to group my data by one attribute of myStruct - LogData:

public class LogData {

    public String           m_Host;
    public String           m_Timestamp;
    public String           m_Request;
    public Integer          m_Reply;
    public String           m_ColumnByteReply;
}

What I tried:

JavaPairRDD <String, Iterable<LogData>> tmp = parsedData.groupBy(logData -> logData.m_Host);

JavaPairRDD<String, Iterable<LogData>> groupMap = parsedData.groupBy(new Function<LogData, String>() {
            @Override
            public String call(LogData logData) throws Exception {
                return logData.m_Host;
            }
        });

and simple:

JavaPairRDD <String, Iterable<LogData>> tmp = parsedData.groupBy(logData -> logData.m_Host);

And when I try to output resultData my program is failed.

Errors:

18/05/13 20:51:32 ERROR Executor: Exception in task 0.0 in stage 1.0 (TID 1) java.io.NotSerializableException: LogData at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1184) at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1548) at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1509) at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1432) at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1178) at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:348) at org.apache.spark.serializer.JavaSerializationStream.writeObject(JavaSerializer.scala:42) at org.apache.spark.storage.DiskBlockObjectWriter.write(BlockObjectWriter.scala:195) at org.apache.spark.util.collection.ExternalSorter.spillToPartitionFiles(ExternalSorter.scala:370) at org.apache.spark.util.collection.ExternalSorter.insertAll(ExternalSorter.scala:211) at org.apache.spark.shuffle.sort.SortShuffleWriter.write(SortShuffleWriter.scala:65) at org.apache.spark.scheduler.ShuffleMapTask.runTask(ShuffleMapTask.scala:68) at org.apache.spark.scheduler.ShuffleMapTask.runTask(ShuffleMapTask.scala:41) at org.apache.spark.scheduler.Task.run(Task.scala:56) at org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:196) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at java.lang.Thread.run(Thread.java:748) 18/05/13 20:51:32 ERROR TaskSetManager: Task 0.0 in stage 1.0 (TID 1) had a not serializable result: LogData; not retrying 18/05/13 20:51:32 INFO TaskSchedulerImpl: Removed TaskSet 1.0, whose tasks have all completed, from pool 18/05/13 20:51:32 INFO TaskSchedulerImpl: Cancelling stage 1 18/05/13 20:51:32 INFO DAGScheduler: Job 1 failed: count at WordCount.java:92, took 0,088518 s org.apache.spark.SparkException: Job aborted due to stage failure: Task 0.0 in stage 1.0 (TID 1) had a not serializable result: LogData at org.apache.spark.scheduler.DAGScheduler.org$apache$spark$scheduler$DAGScheduler$$failJobAndIndependentStages(DAGScheduler.scala:1214) at org.apache.spark.scheduler.DAGScheduler$$anonfun$abortStage$1.apply(DAGScheduler.scala:1203) at org.apache.spark.scheduler.DAGScheduler$$anonfun$abortStage$1.apply(DAGScheduler.scala:1202) at scala.collection.mutable.ResizableArray$class.foreach(ResizableArray.scala:59) at scala.collection.mutable.ArrayBuffer.foreach(ArrayBuffer.scala:47) at org.apache.spark.scheduler.DAGScheduler.abortStage(DAGScheduler.scala:1202) at org.apache.spark.scheduler.DAGScheduler$$anonfun$handleTaskSetFailed$1.apply(DAGScheduler.scala:696) at org.apache.spark.scheduler.DAGScheduler$$anonfun$handleTaskSetFailed$1.apply(DAGScheduler.scala:696) at scala.Option.foreach(Option.scala:236) at org.apache.spark.scheduler.DAGScheduler.handleTaskSetFailed(DAGScheduler.scala:696) at org.apache.spark.scheduler.DAGSchedulerEventProcessActor$$anonfun$receive$2.applyOrElse(DAGScheduler.scala:1420) at akka.actor.Actor$class.aroundReceive(Actor.scala:465) at org.apache.spark.scheduler.DAGSchedulerEventProcessActor.aroundReceive(DAGScheduler.scala:1375) at akka.actor.ActorCell.receiveMessage(ActorCell.scala:516) at akka.actor.ActorCell.invoke(ActorCell.scala:487) at akka.dispatch.Mailbox.processMailbox(Mailbox.scala:238) at akka.dispatch.Mailbox.run(Mailbox.scala:220) at akka.dispatch.ForkJoinExecutorConfigurator$AkkaForkJoinTask.exec(AbstractDispatcher.scala:393) at scala.concurrent.forkjoin.ForkJoinTask.doExec(ForkJoinTask.java:260) at scala.concurrent.forkjoin.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1339) at scala.concurrent.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979) at scala.concurrent.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107)

Help :) Thank's for your answers!

Unknown Unknown · Accepted Answer · 2018-05-13T18:42:25

Change

public class LogData {
    public String           m_Host;
    public String           m_Timestamp;
    public String           m_Request;
    public Integer          m_Reply;
    public String           m_ColumnByteReply;
}

to

public class LogData implements Serializable  {
    public String           m_Host;
    public String           m_Timestamp;
    public String           m_Request;
    public Integer          m_Reply;
    public String           m_ColumnByteReply;
}

Spark groupBy issue

1 Answers