I think it's a bug. Could you open a ticket here: https://issues.apache.org/jira/browse/SPARK
On Wed, Mar 2, 2016 at 3:46 PM, Andy Sloane <andy.slo...@gmail.com> wrote: > We are seeing something that looks a lot like a regression from spark 1.2. > When we run jobs with multiple threads, we have a crash somewhere inside > getPreferredLocations, as was fixed in SPARK-4454. Except now it's inside > org.apache.spark.MapOutputTrackerMaster.getLocationsWithLargestOutputs > instead of DAGScheduler directly. > > I tried Spark 1.2 post-SPARK-4454 (before this patch it's only slightly > flaky), 1.4.1, and 1.5.2 and all are fine. 1.6.0 immediately crashes on our > threaded test case, though once in a while it passes. > > The stack trace is huge, but starts like this: > > Caused by: java.lang.NullPointerException: null > at > org.apache.spark.MapOutputTrackerMaster.getLocationsWithLargestOutputs(MapOutputTracker.scala:406) > at > org.apache.spark.MapOutputTrackerMaster.getPreferredLocationsForShuffle(MapOutputTracker.scala:366) > at > org.apache.spark.rdd.ShuffledRDD.getPreferredLocations(ShuffledRDD.scala:92) > at > org.apache.spark.rdd.RDD$$anonfun$preferredLocations$2.apply(RDD.scala:257) > at > org.apache.spark.rdd.RDD$$anonfun$preferredLocations$2.apply(RDD.scala:257) > at scala.Option.getOrElse(Option.scala:120) > at org.apache.spark.rdd.RDD.preferredLocations(RDD.scala:256) > at org.apache.spark.scheduler.DAGScheduler.org > $apache$spark$scheduler$DAGScheduler$$getPreferredLocsInternal(DAGScheduler.scala:1545) > > The full trace is available here: > https://gist.github.com/andy256/97611f19924bbf65cf49 > > Does this ring any bells? I will attempt to nail down the commit with git > bisect next. > > Thanks > -Andy > >
