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https://issues.apache.org/jira/browse/SPARK-1769?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Aaron Davidson resolved SPARK-1769.
-----------------------------------
Resolution: Fixed
> Executor loss can cause race condition in Pool
> ----------------------------------------------
>
> Key: SPARK-1769
> URL: https://issues.apache.org/jira/browse/SPARK-1769
> Project: Spark
> Issue Type: Bug
> Components: Spark Core
> Affects Versions: 1.0.0
> Reporter: Aaron Davidson
> Assignee: Andrew Or
>
> Loss of executors (in this case due to OOMs) exposes a race condition in
> Pool.scala, evident from this stack trace:
> {code}
> 14/05/08 22:41:48 ERROR OneForOneStrategy:
> java.lang.NullPointerException
> at
> org.apache.spark.scheduler.Pool$$anonfun$executorLost$1.apply(Pool.scala:87)
> at
> org.apache.spark.scheduler.Pool$$anonfun$executorLost$1.apply(Pool.scala:87)
> at
> scala.collection.mutable.ResizableArray$class.foreach(ResizableArray.scala:59)
> at scala.collection.mutable.ArrayBuffer.foreach(ArrayBuffer.scala:47)
> at org.apache.spark.scheduler.Pool.executorLost(Pool.scala:87)
> at
> org.apache.spark.scheduler.Pool$$anonfun$executorLost$1.apply(Pool.scala:87)
> at
> org.apache.spark.scheduler.Pool$$anonfun$executorLost$1.apply(Pool.scala:87)
> at
> scala.collection.mutable.ResizableArray$class.foreach(ResizableArray.scala:59)
> at scala.collection.mutable.ArrayBuffer.foreach(ArrayBuffer.scala:47)
> at org.apache.spark.scheduler.Pool.executorLost(Pool.scala:87)
> at
> org.apache.spark.scheduler.TaskSchedulerImpl.removeExecutor(TaskSchedulerImpl.scala:412)
> at
> org.apache.spark.scheduler.TaskSchedulerImpl.executorLost(TaskSchedulerImpl.scala:385)
> at
> org.apache.spark.scheduler.cluster.CoarseGrainedSchedulerBackend$DriverActor.removeExecutor(CoarseGrainedSchedulerBackend.scala:160)
> at
> org.apache.spark.scheduler.cluster.CoarseGrainedSchedulerBackend$DriverActor$$anonfun$receive$1$$anonfun$applyOrElse$5.apply(CoarseGrainedSchedulerBackend.scala:123)
> at
> org.apache.spark.scheduler.cluster.CoarseGrainedSchedulerBackend$DriverActor$$anonfun$receive$1$$anonfun$applyOrElse$5.apply(CoarseGrainedSchedulerBackend.scala:123)
> at scala.Option.foreach(Option.scala:236)
> at
> org.apache.spark.scheduler.cluster.CoarseGrainedSchedulerBackend$DriverActor$$anonfun$receive$1.applyOrElse(CoarseGrainedSchedulerBackend.scala:123)
> at akka.actor.ActorCell.receiveMessage(ActorCell.scala:498)
> at akka.actor.ActorCell.invoke(ActorCell.scala:456)
> at akka.dispatch.Mailbox.processMailbox(Mailbox.scala:237)
> at akka.dispatch.Mailbox.run(Mailbox.scala:219)
> at
> akka.dispatch.ForkJoinExecutorConfigurator$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)
> {code}
> Note that the line of code that throws this exception is here:
> {code}
> schedulableQueue.foreach(_.executorLost(executorId, host))
> {code}
> By the stack trace, it's not schedulableQueue that is null, but an element
> therein. As far as I could tell, we never add a null element to this queue.
> Rather, I could see that removeSchedulable() and executorLost() were called
> at about the same time (via log messages), and suspect that since this
> ArrayBuffer is in no way synchronized, that we iterate through the list while
> it's in an incomplete state.
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