Hi all,
I tried to use accumulators without any success so far.
My code is simple:
val sc = new SparkContext(conf)
val accum = sc.accumulator(0)
val partialStats = sc.textFile(f.getAbsolutePath())
.map(line => { val key = line.split("\t").head; (key , line)} )
.groupByKey(128)
.mapPartitions{iter => { accum += 1; foo(iter)}}
.reduce(_ + _)
println(accum.value)
Now, if I remove the 'accum += 1', everything works fine. If I keep it, I
get this weird error:
Exception in thread "main" 14/10/25 21:58:56 INFO TaskSchedulerImpl:
Cancelling stage 0
org.apache.spark.SparkException: Job aborted due to stage failure: Task not
serializable: java.io.NotSerializableException:
org.apache.spark.SparkContext
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$$anonfun$handleTaskCompletion$16$$anonfun$apply$1.apply$mcVI$sp(DAGScheduler.scala:890)
at
org.apache.spark.scheduler.DAGScheduler$$anonfun$handleTaskCompletion$16$$anonfun$apply$1.apply(DAGScheduler.scala:887)
at
org.apache.spark.scheduler.DAGScheduler$$anonfun$handleTaskCompletion$16$$anonfun$apply$1.apply(DAGScheduler.scala:887)
at scala.Option.foreach(Option.scala:236)
at
org.apache.spark.scheduler.DAGScheduler$$anonfun$handleTaskCompletion$16.apply(DAGScheduler.scala:887)
at
org.apache.spark.scheduler.DAGScheduler$$anonfun$handleTaskCompletion$16.apply(DAGScheduler.scala:886)
at
scala.collection.mutable.ResizableArray$class.foreach(ResizableArray.scala:59)
at scala.collection.mutable.ArrayBuffer.foreach(ArrayBuffer.scala:47)
at
org.apache.spark.scheduler.DAGScheduler.handleTaskCompletion(DAGScheduler.scala:886)
at
org.apache.spark.scheduler.DAGSchedulerEventProcessActor$$anonfun$receive$2.applyOrElse(DAGScheduler.scala:1204)
at akka.actor.ActorCell.receiveMessage(ActorCell.scala:498)
at akka.actor.ActorCell.invoke(ActorCell.scala:456)
at akka.dispatch.Mailbox.processMailbox(Mailbox.scala:237)
at akka.dispatch.Mailbox.run(Mailbox.scala:219)
at
akka.dispatch.ForkJoinExecutorConfigurator$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)
Can someone please help!
Thank you!
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