Don't write zero block files with java serializer

1 files changed, 26 insertions, 0 deletions

diff --git a/core/src/test/scala/spark/ShuffleSuite.scala b/core/src/test/scala/spark/ShuffleSuite.scala
index b967016cf7..33b02fff80 100644
--- a/core/src/test/scala/spark/ShuffleSuite.scala
+++ b/core/src/test/scala/spark/ShuffleSuite.scala
@@ -367,6 +367,32 @@ class ShuffleSuite extends FunSuite with ShouldMatchers with LocalSparkContext {
     assert(nonEmptyBlocks.size <= 4)
   }
 
+  test("zero sized blocks without kryo") {
+    // Use a local cluster with 2 processes to make sure there are both local and remote blocks
+    sc = new SparkContext("local-cluster[2,1,512]", "test")
+
+    // 10 partitions from 4 keys
+    val NUM_BLOCKS = 10
+    val a = sc.parallelize(1 to 4, NUM_BLOCKS)
+    val b = a.map(x => (x, x*2))
+
+    // NOTE: The default Java serializer doesn't create zero-sized blocks.
+    //       So, use Kryo
+    val c = new ShuffledRDD(b, new HashPartitioner(10))
+
+    val shuffleId = c.dependencies.head.asInstanceOf[ShuffleDependency[Int, Int]].shuffleId
+    assert(c.count === 4)
+
+    val blockSizes = (0 until NUM_BLOCKS).flatMap { id =>
+      val statuses = SparkEnv.get.mapOutputTracker.getServerStatuses(shuffleId, id)
+      statuses.map(x => x._2)
+    }
+    val nonEmptyBlocks = blockSizes.filter(x => x > 0)
+
+    // We should have at most 4 non-zero sized partitions
+    assert(nonEmptyBlocks.size <= 4)
+  }
+
 }
 
 object ShuffleSuite {