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Diffstat (limited to 'core')
| -rw-r--r-- | core/src/main/scala/org/apache/spark/MapOutputTracker.scala | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/core/src/main/scala/org/apache/spark/MapOutputTracker.scala b/core/src/main/scala/org/apache/spark/MapOutputTracker.scala index fbda11f578..10fae5af9f 100644 --- a/core/src/main/scala/org/apache/spark/MapOutputTracker.scala +++ b/core/src/main/scala/org/apache/spark/MapOutputTracker.scala @@ -72,6 +72,13 @@ private[spark] class MapOutputTracker extends Logging { // throw a SparkException if this fails. private def askTracker(message: Any): Any = { try { + /* + The difference between ActorRef and ActorSelection is well explained here: + http://doc.akka.io/docs/akka/2.2.3/project/migration-guide-2.1.x-2.2.x.html#Use_actorSelection_instead_of_actorFor + In spark a map output tracker can be either started on Driver where it is created which + is an ActorRef or it can be on executor from where it is looked up which is an + actorSelection. + */ val future = trackerActor match { case Left(a: ActorRef) => a.ask(message)(timeout) case Right(b: ActorSelection) => b.ask(message)(timeout) |