SPARK-1337: Application web UI garbage collects newest stages

Simple fix...

Author: Patrick Wendell <pwendell@gmail.com>

Closes #320 from pwendell/stage-clean-up and squashes the following commits:

29be62e [Patrick Wendell] SPARK-1337: Application web UI garbage collects newest stages instead old ones

1 files changed, 4 insertions, 4 deletions

diff --git a/core/src/main/scala/org/apache/spark/ui/jobs/JobProgressListener.scala b/core/src/main/scala/org/apache/spark/ui/jobs/JobProgressListener.scala
index d10aa12b9e..cd4be57227 100644
--- a/core/src/main/scala/org/apache/spark/ui/jobs/JobProgressListener.scala
+++ b/core/src/main/scala/org/apache/spark/ui/jobs/JobProgressListener.scala
@@ -81,8 +81,8 @@ private[ui] class JobProgressListener(conf: SparkConf) extends SparkListener {
   /** If stages is too large, remove and garbage collect old stages */
   private def trimIfNecessary(stages: ListBuffer[StageInfo]) = synchronized {
     if (stages.size > retainedStages) {
-      val toRemove = retainedStages / 10
-      stages.takeRight(toRemove).foreach( s => {
+      val toRemove = math.max(retainedStages / 10, 1)
+      stages.take(toRemove).foreach { s =>
         stageIdToTaskData.remove(s.stageId)
         stageIdToTime.remove(s.stageId)
         stageIdToShuffleRead.remove(s.stageId)
@@ -94,8 +94,8 @@ private[ui] class JobProgressListener(conf: SparkConf) extends SparkListener {
         stageIdToTasksFailed.remove(s.stageId)
         stageIdToPool.remove(s.stageId)
         if (stageIdToDescription.contains(s.stageId)) {stageIdToDescription.remove(s.stageId)}
-      })
-      stages.trimEnd(toRemove)
+      }
+      stages.trimStart(toRemove)
     }
   }