Hi Andrew,
Sorry, I can not reproduce the issue by:
scala> import org.apache.spark.rdd.RDD
scala> val myRDD: RDD[(String,Int)] = sc.parallelize(Seq( ("A",10),
("B",5), ("A",4), ("C", 15)))
scala> myRDD.reduceByKey(_+_).top(2)
Any different compare with your example ?
On Fri, Feb 14, 2014 at 7:38 PM, Andrew Ash <[email protected]> wrote:
> Spark 0.9.0
>
>
> Hi Spark devs,
>
> I'm pretty sure this stacktrace is a bug in the way Spark is using the type
> system but I don't quite know what it is. Something to do with type bounds
> judging from my Googling.
>
> Can someone with more Scala-foo than me please take a look? In the
> meantime I'll be avoiding top() for a bit.
>
> Thanks!
> Andrew
>
>
>
> This stracktrace came about when I called
> val myRDD: RDD[(String,Int)] = ...
> myRDD.reduceByKey(_+_).top(100)
>
> But my toy example doesn't trigger the repro:
> sc.parallelize(Seq( ("A",10), ("B",5), ("A",4), ("C", 15)
> )).reduceByKey(_+_).top(2)
>
>
>
> 14/02/14 03:15:07 ERROR OneForOneStrategy:
> scala.collection.immutable.$colon$colon cannot be cast to
> org.apache.spark.util.BoundedPriorityQueue
> java.lang.ClassCastException: scala.collection.immutable.$colon$colon
> cannot be cast to org.apache.spark.util.BoundedPriorityQueue
> at org.apache.spark.rdd.RDD$$anonfun$top$2.apply(RDD.scala:873)
> at org.apache.spark.rdd.RDD$$anonfun$6.apply(RDD.scala:671)
> at org.apache.spark.rdd.RDD$$anonfun$6.apply(RDD.scala:668)
> at
> org.apache.spark.scheduler.JobWaiter.taskSucceeded(JobWaiter.scala:56)
> at
>
> org.apache.spark.scheduler.DAGScheduler.handleTaskCompletion(DAGScheduler.scala:859)
> at
>
> org.apache.spark.scheduler.DAGScheduler.processEvent(DAGScheduler.scala:616)
> at
>
> org.apache.spark.scheduler.DAGScheduler$$anonfun$start$1$$anon$2$$anonfun$receive$1.applyOrElse(DAGScheduler.scala:207)
> at akka.actor.ActorCell.receiveMessage(ActorCell.scala:498)
> at akka.actor.ActorCell.invoke(ActorCell.scala:456)
> at akka.dispatch.Mailbox.processMailbox(Mailbox.scala:237)
> at akka.dispatch.Mailbox.run(Mailbox.scala:219)
> at
>
> akka.dispatch.ForkJoinExecutorConfigurator$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)
>
--
~Yours, Xuefeng Wu/吴雪峰 敬上
