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Posted to issues@spark.apache.org by "Aaron Davidson (JIRA)" <ji...@apache.org> on 2014/05/14 09:57:14 UTC
[jira] [Resolved] (SPARK-1769) Executor loss can cause race
condition in Pool
[ 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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