Github user ueshin commented on a diff in the pull request:

    https://github.com/apache/spark/pull/12060#discussion_r58481389
  
    --- Diff: core/src/main/scala/org/apache/spark/scheduler/DAGScheduler.scala 
---
    @@ -403,32 +403,47 @@ class DAGScheduler(
         parents.toList
       }
     
    -  /** Find ancestor shuffle dependencies that are not registered in 
shuffleToMapStage yet */
    -  private def getAncestorShuffleDependencies(rdd: RDD[_]): 
Stack[ShuffleDependency[_, _, _]] = {
    -    val parents = new Stack[ShuffleDependency[_, _, _]]
    +  /**
    +   * Find ancestor shuffle dependencies that are not registered in 
shuffleToMapStage yet.
    +   * This is done in topological order to create ancestor stages first to 
ensure that the result
    +   * stage graph is correctly built.
    +   */
    +  private def getAncestorShuffleDependencies(rdd: RDD[_]): 
Seq[ShuffleDependency[_, _, _]] = {
    +    val parents = new ArrayBuffer[ShuffleDependency[_, _, _]]
         val visited = new HashSet[RDD[_]]
         // We are manually maintaining a stack here to prevent 
StackOverflowError
         // caused by recursively visiting
         val waitingForVisit = new Stack[RDD[_]]
         def visit(r: RDD[_]) {
           if (!visited(r)) {
    -        visited += r
    -        for (dep <- r.dependencies) {
    -          dep match {
    -            case shufDep: ShuffleDependency[_, _, _] =>
    -              if (!shuffleToMapStage.contains(shufDep.shuffleId)) {
    -                parents.push(shufDep)
    -              }
    -            case _ =>
    +        val deps = r.dependencies.filter {
    +          case shufDep: ShuffleDependency[_, _, _] =>
    +            !shuffleToMapStage.contains(shufDep.shuffleId)
    +          case _ => true
    +        }
    +        if (deps.forall(dep => visited(dep.rdd))) {
    +          waitingForVisit.pop()
    +          visited += r
    +          for (dep <- deps) {
    +            dep match {
    +              case shufDep: ShuffleDependency[_, _, _] =>
    +                parents += shufDep
    +              case _ =>
    +            }
    +          }
    +        } else {
    +          for (dep <- deps if !visited(dep.rdd)) {
    +            waitingForVisit.push(dep.rdd)
               }
    -          waitingForVisit.push(dep.rdd)
             }
    +      } else {
    +        waitingForVisit.pop()
           }
         }
     
    --- End diff --
    
    @markhamstra Thank you, I'll pick it.


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