diff --git a/streaming/src/main/scala/spark/streaming/DStream.scala b/streaming/src/main/scala/spark/streaming/DStream.scala index e1be5ef51cc9cd8cc4c71c52b6f8dcb820dbb761..e3a9247924f12c2f771533fbeb54158753cd85c2 100644 --- a/streaming/src/main/scala/spark/streaming/DStream.scala +++ b/streaming/src/main/scala/spark/streaming/DStream.scala @@ -441,7 +441,10 @@ abstract class DStream[T: ClassManifest] ( * Return a new DStream in which each RDD has a single element generated by counting each RDD * of this DStream. */ - def count(): DStream[Long] = this.map(_ => 1L).reduce(_ + _) + def count(): DStream[Long] = { + val zero = new ConstantInputDStream(context, context.sparkContext.makeRDD(Seq((null, 0L)), 1)) + this.map(_ => (null, 1L)).union(zero).reduceByKey(_ + _).map(_._2) + } /** * Return a new DStream in which each RDD contains the counts of each distinct value in diff --git a/streaming/src/test/scala/spark/streaming/BasicOperationsSuite.scala b/streaming/src/test/scala/spark/streaming/BasicOperationsSuite.scala index 8fce91853c77eed0f5d3e5e48aa2e93f13988e3e..168e1b7a557c963a98a81683ffe88d089ca7391a 100644 --- a/streaming/src/test/scala/spark/streaming/BasicOperationsSuite.scala +++ b/streaming/src/test/scala/spark/streaming/BasicOperationsSuite.scala @@ -90,9 +90,9 @@ class BasicOperationsSuite extends TestSuiteBase { test("count") { testOperation( - Seq(1 to 1, 1 to 2, 1 to 3, 1 to 4), + Seq(Seq(), 1 to 1, 1 to 2, 1 to 3, 1 to 4), (s: DStream[Int]) => s.count(), - Seq(Seq(1L), Seq(2L), Seq(3L), Seq(4L)) + Seq(Seq(0L), Seq(1L), Seq(2L), Seq(3L), Seq(4L)) ) }