History Server: updated order for multiple attempts(descending start time works everytime)

Author: rekhajoshm

core/src/main/scala/org/apache/spark/deploy/history/FsHistoryProvider.scala

@@ -413,8 +413,8 @@ private[history] class FsHistoryProvider(conf: SparkConf, clock: Clock)
 
   /**
    * Comparison function that defines the sort order for application attempts within the same
-   * application. Order is: completed attempts before running attempts, if both completed
-   * or both running attempts sorted by descending start time.
+   * application. Order is: later attempts before earlier attempts.
+   * The most recent attempt state matches with current state of the app.
    *
    * Normally applications should have a single running attempt; but failure to call sc.stop()
    * may cause multiple running attempts to show up.
@@ -424,11 +424,7 @@ private[history] class FsHistoryProvider(conf: SparkConf, clock: Clock)
   private def compareAttemptInfo(
       a1: FsApplicationAttemptInfo,
       a2: FsApplicationAttemptInfo): Boolean = {
-    if (a1.completed == a2.completed) {
-      a1.startTime >= a2.startTime
-    } else {
-      a1.completed
-    }
+    a1.startTime >= a2.startTime
   }
 
   /**