[SPARK-9144] Remove DAGScheduler.runLocallyWithinThread and spark.loc…

…alExecution.enabled

Spark has an option called spark.localExecution.enabled; according to the docs:

> Enables Spark to run certain jobs, such as first() or take() on the driver, without sending tasks to the cluster. This can make certain jobs execute very quickly, but may require shipping a whole partition of data to the driver.

This feature ends up adding quite a bit of complexity to DAGScheduler, especially in the runLocallyWithinThread method, but as far as I know nobody uses this feature (I searched the mailing list and haven't seen any recent mentions of the configuration nor stacktraces including the runLocally method). As a step towards scheduler complexity reduction, I propose that we remove this feature and all code related to it for Spark 1.5.

This pull request simply brings #7484 up to date.

Author: Josh Rosen <joshrosen@databricks.com>
Author: Reynold Xin <rxin@databricks.com>

Closes #7585 from rxin/remove-local-exec and squashes the following commits:

84bd10e [Reynold Xin] Python fix.
1d9739a [Reynold Xin] Merge pull request #7484 from JoshRosen/remove-localexecution
eec39fa [Josh Rosen] Remove allowLocal(); deprecate user-facing uses of it.
b0835dc [Josh Rosen] Remove local execution code in DAGScheduler
8975d96 [Josh Rosen] Remove local execution tests.
ffa8c9b [Josh Rosen] Remove documentation for configuration

core/src/main/scala/org/apache/spark/SparkContext.scala

@@ -1758,16 +1758,13 @@ class SparkContext(config: SparkConf) extends Logging with ExecutorAllocationCli
 
   /**
    * Run a function on a given set of partitions in an RDD and pass the results to the given
-   * handler function. This is the main entry point for all actions in Spark. The allowLocal
-   * flag specifies whether the scheduler can run the computation on the driver rather than
-   * shipping it out to the cluster, for short actions like first().
+   * handler function. This is the main entry point for all actions in Spark.
    */
   def runJob[T, U: ClassTag](
       rdd: RDD[T],
       func: (TaskContext, Iterator[T]) => U,
       partitions: Seq[Int],
-      allowLocal: Boolean,
-      resultHandler: (Int, U) => Unit) {
+      resultHandler: (Int, U) => Unit): Unit = {
     if (stopped.get()) {
       throw new IllegalStateException("SparkContext has been shutdown")
     }
@@ -1777,54 +1774,104 @@ class SparkContext(config: SparkConf) extends Logging with ExecutorAllocationCli
     if (conf.getBoolean("spark.logLineage", false)) {
       logInfo("RDD's recursive dependencies:\n" + rdd.toDebugString)
     }
-    dagScheduler.runJob(rdd, cleanedFunc, partitions, callSite, allowLocal,
-      resultHandler, localProperties.get)
+    dagScheduler.runJob(rdd, cleanedFunc, partitions, callSite, resultHandler, localProperties.get)
     progressBar.foreach(_.finishAll())
     rdd.doCheckpoint()
   }
 
   /**
-   * Run a function on a given set of partitions in an RDD and return the results as an array. The
-   * allowLocal flag specifies whether the scheduler can run the computation on the driver rather
-   * than shipping it out to the cluster, for short actions like first().
+   * Run a function on a given set of partitions in an RDD and return the results as an array.
+   */
+  def runJob[T, U: ClassTag](
+      rdd: RDD[T],
+      func: (TaskContext, Iterator[T]) => U,
+      partitions: Seq[Int]): Array[U] = {
+    val results = new Array[U](partitions.size)
+    runJob[T, U](rdd, func, partitions, (index, res) => results(index) = res)
+    results
+  }
+
+  /**
+   * Run a job on a given set of partitions of an RDD, but take a function of type
+   * `Iterator[T] => U` instead of `(TaskContext, Iterator[T]) => U`.
+   */
+  def runJob[T, U: ClassTag](
+      rdd: RDD[T],
+      func: Iterator[T] => U,
+      partitions: Seq[Int]): Array[U] = {
+    val cleanedFunc = clean(func)
+    runJob(rdd, (ctx: TaskContext, it: Iterator[T]) => cleanedFunc(it), partitions)
+  }
+
+
+  /**
+   * Run a function on a given set of partitions in an RDD and pass the results to the given
+   * handler function. This is the main entry point for all actions in Spark.
+   *
+   * The allowLocal flag is deprecated as of Spark 1.5.0+.
+   */
+  @deprecated("use the version of runJob without the allowLocal parameter", "1.5.0")
+  def runJob[T, U: ClassTag](
+      rdd: RDD[T],
+      func: (TaskContext, Iterator[T]) => U,
+      partitions: Seq[Int],
+      allowLocal: Boolean,
+      resultHandler: (Int, U) => Unit): Unit = {
+    if (allowLocal) {
+      logWarning("sc.runJob with allowLocal=true is deprecated in Spark 1.5.0+")
+    }
+    runJob(rdd, func, partitions, resultHandler)
+  }
+
+  /**
+   * Run a function on a given set of partitions in an RDD and return the results as an array.
+   *
+   * The allowLocal flag is deprecated as of Spark 1.5.0+.
    */
+  @deprecated("use the version of runJob without the allowLocal parameter", "1.5.0")
   def runJob[T, U: ClassTag](
       rdd: RDD[T],
       func: (TaskContext, Iterator[T]) => U,
       partitions: Seq[Int],
       allowLocal: Boolean
       ): Array[U] = {
-    val results = new Array[U](partitions.size)
-    runJob[T, U](rdd, func, partitions, allowLocal, (index, res) => results(index) = res)
-    results
+    if (allowLocal) {
+      logWarning("sc.runJob with allowLocal=true is deprecated in Spark 1.5.0+")
+    }
+    runJob(rdd, func, partitions)
   }
 
   /**
    * Run a job on a given set of partitions of an RDD, but take a function of type
    * `Iterator[T] => U` instead of `(TaskContext, Iterator[T]) => U`.
+   *
+   * The allowLocal argument is deprecated as of Spark 1.5.0+.
    */
+  @deprecated("use the version of runJob without the allowLocal parameter", "1.5.0")
   def runJob[T, U: ClassTag](
       rdd: RDD[T],
       func: Iterator[T] => U,
       partitions: Seq[Int],
       allowLocal: Boolean
       ): Array[U] = {
-    val cleanedFunc = clean(func)
-    runJob(rdd, (ctx: TaskContext, it: Iterator[T]) => cleanedFunc(it), partitions, allowLocal)
+    if (allowLocal) {
+      logWarning("sc.runJob with allowLocal=true is deprecated in Spark 1.5.0+")
+    }
+    runJob(rdd, func, partitions)
   }
 
   /**
    * Run a job on all partitions in an RDD and return the results in an array.
    */
   def runJob[T, U: ClassTag](rdd: RDD[T], func: (TaskContext, Iterator[T]) => U): Array[U] = {
-    runJob(rdd, func, 0 until rdd.partitions.size, false)
+    runJob(rdd, func, 0 until rdd.partitions.length)
   }
 
   /**
    * Run a job on all partitions in an RDD and return the results in an array.
    */
   def runJob[T, U: ClassTag](rdd: RDD[T], func: Iterator[T] => U): Array[U] = {
-    runJob(rdd, func, 0 until rdd.partitions.size, false)
+    runJob(rdd, func, 0 until rdd.partitions.length)
   }
 
   /**
@@ -1835,7 +1882,7 @@ class SparkContext(config: SparkConf) extends Logging with ExecutorAllocationCli
     processPartition: (TaskContext, Iterator[T]) => U,
     resultHandler: (Int, U) => Unit)
   {
-    runJob[T, U](rdd, processPartition, 0 until rdd.partitions.size, false, resultHandler)
+    runJob[T, U](rdd, processPartition, 0 until rdd.partitions.length, resultHandler)
   }
 
   /**
@@ -1847,7 +1894,7 @@ class SparkContext(config: SparkConf) extends Logging with ExecutorAllocationCli
       resultHandler: (Int, U) => Unit)
   {
     val processFunc = (context: TaskContext, iter: Iterator[T]) => processPartition(iter)
-    runJob[T, U](rdd, processFunc, 0 until rdd.partitions.size, false, resultHandler)
+    runJob[T, U](rdd, processFunc, 0 until rdd.partitions.length, resultHandler)
   }
 
   /**
@@ -1892,7 +1939,6 @@ class SparkContext(config: SparkConf) extends Logging with ExecutorAllocationCli
       (context: TaskContext, iter: Iterator[T]) => cleanF(iter),
       partitions,
       callSite,
-      allowLocal = false,
       resultHandler,
       localProperties.get)
     new SimpleFutureAction(waiter, resultFunc)

core/src/main/scala/org/apache/spark/api/java/JavaRDDLike.scala

@@ -364,7 +364,7 @@ trait JavaRDDLike[T, This <: JavaRDDLike[T, This]] extends Serializable {
     // This is useful for implementing `take` from other language frontends
     // like Python where the data is serialized.
     import scala.collection.JavaConversions._
-    val res = context.runJob(rdd, (it: Iterator[T]) => it.toArray, partitionIds, true)
+    val res = context.runJob(rdd, (it: Iterator[T]) => it.toArray, partitionIds)
     res.map(x => new java.util.ArrayList(x.toSeq)).toArray
   }
 

core/src/main/scala/org/apache/spark/api/python/PythonRDD.scala

@@ -358,12 +358,11 @@ private[spark] object PythonRDD extends Logging {
   def runJob(
       sc: SparkContext,
       rdd: JavaRDD[Array[Byte]],
-      partitions: JArrayList[Int],
-      allowLocal: Boolean): Int = {
+      partitions: JArrayList[Int]): Int = {
     type ByteArray = Array[Byte]
     type UnrolledPartition = Array[ByteArray]
     val allPartitions: Array[UnrolledPartition] =
-      sc.runJob(rdd, (x: Iterator[ByteArray]) => x.toArray, partitions, allowLocal)
+      sc.runJob(rdd, (x: Iterator[ByteArray]) => x.toArray, partitions)
     val flattenedPartition: UnrolledPartition = Array.concat(allPartitions: _*)
     serveIterator(flattenedPartition.iterator,
       s"serve RDD ${rdd.id} with partitions ${partitions.mkString(",")}")

core/src/main/scala/org/apache/spark/executor/Executor.scala

@@ -215,8 +215,6 @@ private[spark] class Executor(
             attemptNumber = attemptNumber,
             metricsSystem = env.metricsSystem)
         } finally {
-          // Note: this memory freeing logic is duplicated in DAGScheduler.runLocallyWithinThread;
-          // when changing this, make sure to update both copies.
           val freedMemory = taskMemoryManager.cleanUpAllAllocatedMemory()
           if (freedMemory > 0) {
             val errMsg = s"Managed memory leak detected; size = $freedMemory bytes, TID = $taskId"

core/src/main/scala/org/apache/spark/rdd/PairRDDFunctions.scala

@@ -881,7 +881,7 @@ class PairRDDFunctions[K, V](self: RDD[(K, V)])
           }
           buf
         } : Seq[V]
-        val res = self.context.runJob(self, process, Array(index), false)
+        val res = self.context.runJob(self, process, Array(index))
         res(0)
       case None =>
         self.filter(_._1 == key).map(_._2).collect()

core/src/main/scala/org/apache/spark/rdd/RDD.scala

@@ -897,7 +897,7 @@ abstract class RDD[T: ClassTag](
    */
   def toLocalIterator: Iterator[T] = withScope {
     def collectPartition(p: Int): Array[T] = {
-      sc.runJob(this, (iter: Iterator[T]) => iter.toArray, Seq(p), allowLocal = false).head
+      sc.runJob(this, (iter: Iterator[T]) => iter.toArray, Seq(p)).head
     }
     (0 until partitions.length).iterator.flatMap(i => collectPartition(i))
   }
@@ -1273,7 +1273,7 @@ abstract class RDD[T: ClassTag](
 
         val left = num - buf.size
         val p = partsScanned until math.min(partsScanned + numPartsToTry, totalParts)
-        val res = sc.runJob(this, (it: Iterator[T]) => it.take(left).toArray, p, allowLocal = true)
+        val res = sc.runJob(this, (it: Iterator[T]) => it.take(left).toArray, p)
 
         res.foreach(buf ++= _.take(num - buf.size))
         partsScanned += numPartsToTry

core/src/main/scala/org/apache/spark/rdd/ZippedWithIndexRDD.scala

@@ -50,8 +50,7 @@ class ZippedWithIndexRDD[T: ClassTag](@transient prev: RDD[T]) extends RDD[(T, L
       prev.context.runJob(
         prev,
         Utils.getIteratorSize _,
-        0 until n - 1, // do not need to count the last partition
-        allowLocal = false
+        0 until n - 1 // do not need to count the last partition
       ).scanLeft(0L)(_ + _)
     }
   }