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From Aaron Davidson <ilike...@gmail.com>
Subject Re: DAGScheduler: Failed to run foreach
Date Tue, 24 Jun 2014 01:00:27 GMT
Please note that this:

for (sentence <- sourcerdd) {
   ...
}

is actually Scala syntactic sugar which is converted into

sourcerdd.foreach { sentence => ... }

What this means is that this will actually run on the cluster, which is
probably not what you want if you're trying to print them.

Try this instead:

for (sentence <- sourcerdd.toLocalIterator) {
  ...
}

(By the way, the reason this was throwing a NotSerializableException was
because you were trying to pass "printScoreCanndedString" as part of the
job's closure. In Java, class methods have an implicit reference to "this",
so it tried to serialize the class CalculateScore, which is presumably not
marked as Serializable.)


On Mon, Jun 23, 2014 at 5:45 PM, Sameer Tilak <sstilak@live.com> wrote:

> The subject should be: org.apache.spark.SparkException: Job aborted due
> to stage failure: Task not serializable: java.io.NotSerializableException:
>  and not DAGScheduler: Failed to run foreach
>
> If I call printScoreCanndedString with a hard-coded string and identical
> 2nd parameter, it works fine. However for my application that is not
> sufficient.
> ------------------------------
> From: sstilak@live.com
> To: user@spark.incubator.apache.org
> Subject: DAGScheduler: Failed to run foreach
> Date: Mon, 23 Jun 2014 17:05:03 -0700
>
>
> Hi All,
>
> I am using spark for text analysis. I have a source file that has few
> thousand sentences and a dataset of tens of millions of statements. I want
> to compare each statement from the sourceFile with each statement from the
> dataset and generate a score. I am having following problem. I would really
> appreciate help.
>
> Here is what I do within spark-shell
>
> // Source file with few thousand sentences
>  val srcFile = sc.textFile("hdfs://serverip/data/dummy/src.txt");
>
> // Dataset with tens of millions of statements.
>
>  val destFile = sc.textFile("hdfs://serverip/data/dummy/sample.txt");
>
> // Initialize the score variable.
>
>  val score = new mypackage.Score()
>
> // Generate score.
>
> score.calculateScore(srcFile, destFile);
>
> Here is my snippet from my scala class (Score.scala)
>
>
>   def calculateScore (sourcerdd: RDD[String], destrdd: RDD[String])  {
>     for (sentence <- sourcerdd)
>    {
>       println("Source String is: " + sentence + "Data Type is: " +
> sentence.getClass.getSimpleName)
>
>       printScoreCanndedString(sentence, destrdd);
>    }
>
>   }
>     def printScoreCanndedString(sourceStr: String,rdd: RDD[String]) :
> RDD[Double] = {
>     // Do the analysis here.
>     }
>
> The print statement displays the data correctly along with data type as
> String as expected. However, I get the following error message when it
> tries to execute  printScoreCanndedString method. Any help with this will
> be great.
>
>
> 14/06/23 16:45:04 WARN NativeCodeLoader: Unable to load native-hadoop
> library for your platform... using builtin-java classes where applicable
> 14/06/23 16:45:04 WARN LoadSnappy: Snappy native library not loaded
> 14/06/23 16:45:04 INFO FileInputFormat: Total input paths to process : 1
> 14/06/23 16:45:04 INFO SparkContext: Starting job: foreach at
> calculateScore.scala:51
> 14/06/23 16:45:04 INFO DAGScheduler: Got job 0 (foreach at
> CalculateScore.scala:51) with 2 output partitions (allowLocal=false)
> 14/06/23 16:45:04 INFO DAGScheduler: Final stage: Stage 0(foreach
> at CalculateScore.scala:51)
> 14/06/23 16:45:04 INFO DAGScheduler: Parents of final stage: List()
> 14/06/23 16:45:04 INFO DAGScheduler: Missing parents: List()
> 14/06/23 16:45:04 INFO DAGScheduler: Submitting Stage 0 (MappedRDD[1] at
> textFile at <console>:12), which has no missing parents
> 14/06/23 16:45:04 INFO DAGScheduler: Failed to run foreach
> at CalculateScore.scala:51
> org.apache.spark.SparkException: Job aborted due to stage failure: Task
> not serializable: java.io.NotSerializableException: approxstrmatch.
> CalculateScore
>  at org.apache.spark.scheduler.DAGScheduler.org
> $apache$spark$scheduler$DAGScheduler$$failJobAndIndependentStages(DAGScheduler.scala:1033)
>  at
> org.apache.spark.scheduler.DAGScheduler$$anonfun$abortStage$1.apply(DAGScheduler.scala:1017)
> at
> org.apache.spark.scheduler.DAGScheduler$$anonfun$abortStage$1.apply(DAGScheduler.scala:1015)
>  at
> scala.collection.mutable.ResizableArray$class.foreach(ResizableArray.scala:59)
> at scala.collection.mutable.ArrayBuffer.foreach(ArrayBuffer.scala:47)
>  at
> org.apache.spark.scheduler.DAGScheduler.abortStage(DAGScheduler.scala:1015)
> at org.apache.spark.scheduler.DAGScheduler.org
> $apache$spark$scheduler$DAGScheduler$$submitMissingTasks(DAGScheduler.scala:770)
>  at org.apache.spark.scheduler.DAGScheduler.org
> $apache$spark$scheduler$DAGScheduler$$submitStage(DAGScheduler.scala:713)
>  at
> org.apache.spark.scheduler.DAGScheduler.handleJobSubmitted(DAGScheduler.scala:697)
> at
> org.apache.spark.scheduler.DAGSchedulerEventProcessActor$$anonfun$receive$2.applyOrElse(DAGScheduler.scala:1176)
>  at akka.actor.ActorCell.receiveMessage(ActorCell.scala:498)
> at akka.actor.ActorCell.invoke(ActorCell.scala:456)
>  at akka.dispatch.Mailbox.processMailbox(Mailbox.scala:237)
> at akka.dispatch.Mailbox.run(Mailbox.scala:219)
> at
> akka.dispatch.ForkJoinExecutorConfigurator$AkkaForkJoinTask.exec(AbstractDispatcher.scala:386)
>  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)
>

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