Repository: spark Updated Branches: refs/heads/branch-1.2 14dbd8312 -> 434ea009c
[SPARK-5035] [Streaming] ReceiverMessage trait should extend Serializable Spark Streaming's ReceiverMessage trait should extend Serializable in order to fix a subtle bug that only occurs when running on a real cluster: If you attempt to send a fire-and-forget message to a remote Akka actor and that message cannot be serialized, then this seems to lead to more-or-less silent failures. As an optimization, Akka skips message serialization for messages sent within the same JVM. As a result, Spark's unit tests will never fail due to non-serializable Akka messages, but these will cause mostly-silent failures when running on a real cluster. Before this patch, here was the code for ReceiverMessage: ``` /** Messages sent to the NetworkReceiver. */ private[streaming] sealed trait ReceiverMessage private[streaming] object StopReceiver extends ReceiverMessage ``` Since ReceiverMessage does not extend Serializable and StopReceiver is a regular `object`, not a `case object`, StopReceiver will throw serialization errors. As a result, graceful receiver shutdown is broken on real clusters (and local-cluster mode) but works in local modes. If you want to reproduce this, try running the word count example from the Streaming Programming Guide in the Spark shell: ``` import org.apache.spark._ import org.apache.spark.streaming._ import org.apache.spark.streaming.StreamingContext._ val ssc = new StreamingContext(sc, Seconds(10)) // Create a DStream that will connect to hostname:port, like localhost:9999 val lines = ssc.socketTextStream("localhost", 9999) // Split each line into words val words = lines.flatMap(_.split(" ")) import org.apache.spark.streaming.StreamingContext._ // Count each word in each batch val pairs = words.map(word => (word, 1)) val wordCounts = pairs.reduceByKey(_ + _) // Print the first ten elements of each RDD generated in this DStream to the console wordCounts.print() ssc.start() Thread.sleep(10000) ssc.stop(true, true) ``` Prior to this patch, this would work correctly in local mode but fail when running against a real cluster (it would report that some receivers were not shut down). Author: Josh Rosen <joshro...@databricks.com> Closes #3857 from JoshRosen/SPARK-5035 and squashes the following commits: 71d0eae [Josh Rosen] [SPARK-5035] ReceiverMessage trait should extend Serializable. (cherry picked from commit fe6efacc0b865e9e827a1565877077000e63976e) Signed-off-by: Tathagata Das <tathagata.das1...@gmail.com> Project: http://git-wip-us.apache.org/repos/asf/spark/repo Commit: http://git-wip-us.apache.org/repos/asf/spark/commit/434ea009 Tree: http://git-wip-us.apache.org/repos/asf/spark/tree/434ea009 Diff: http://git-wip-us.apache.org/repos/asf/spark/diff/434ea009 Branch: refs/heads/branch-1.2 Commit: 434ea009cd7efb2c29e88a889e87f501647a7fa6 Parents: 14dbd83 Author: Josh Rosen <joshro...@databricks.com> Authored: Wed Dec 31 16:02:47 2014 -0800 Committer: Tathagata Das <tathagata.das1...@gmail.com> Committed: Wed Dec 31 16:03:03 2014 -0800 ---------------------------------------------------------------------- .../org/apache/spark/streaming/receiver/ReceiverMessage.scala | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) ---------------------------------------------------------------------- http://git-wip-us.apache.org/repos/asf/spark/blob/434ea009/streaming/src/main/scala/org/apache/spark/streaming/receiver/ReceiverMessage.scala ---------------------------------------------------------------------- diff --git a/streaming/src/main/scala/org/apache/spark/streaming/receiver/ReceiverMessage.scala b/streaming/src/main/scala/org/apache/spark/streaming/receiver/ReceiverMessage.scala index bf39d1e..ab9fa19 100644 --- a/streaming/src/main/scala/org/apache/spark/streaming/receiver/ReceiverMessage.scala +++ b/streaming/src/main/scala/org/apache/spark/streaming/receiver/ReceiverMessage.scala @@ -18,6 +18,6 @@ package org.apache.spark.streaming.receiver /** Messages sent to the NetworkReceiver. */ -private[streaming] sealed trait ReceiverMessage +private[streaming] sealed trait ReceiverMessage extends Serializable private[streaming] object StopReceiver extends ReceiverMessage --------------------------------------------------------------------- To unsubscribe, e-mail: commits-unsubscr...@spark.apache.org For additional commands, e-mail: commits-h...@spark.apache.org