YARN-5101. YARN_APPLICATION_UPDATED event is parsed in ApplicationHistoryManagerOnTimelineStore#convertToApplicationReport with reversed order. Contributed by Sunil G.

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-applicationhistoryservice/src/main/java/org/apache/hadoop/yarn/server/applicationhistoryservice/ApplicationHistoryManagerOnTimelineStore.java

@@ -351,6 +351,7 @@ public class ApplicationHistoryManagerOnTimelineStore extends AbstractService
       }
     }
     List<TimelineEvent> events = entity.getEvents();
+    long updatedTimeStamp = 0L;
     if (events != null) {
       for (TimelineEvent event : events) {
         if (event.getEventType().equals(
@@ -358,9 +359,16 @@ public class ApplicationHistoryManagerOnTimelineStore extends AbstractService
           createdTime = event.getTimestamp();
         } else if (event.getEventType().equals(
             ApplicationMetricsConstants.UPDATED_EVENT_TYPE)) {
-          // TODO: YARN-5101. This type of events are parsed in
-          // time-stamp descending order which means the previous event
-          // could override the information from the later same type of event.
+          // This type of events are parsed in time-stamp descending order
+          // which means the previous event could override the information
+          // from the later same type of event. Hence compare timestamp
+          // before over writing.
+          if (event.getTimestamp() > updatedTimeStamp) {
+            updatedTimeStamp = event.getTimestamp();
+          } else {
+            continue;
+          }
+
           Map<String, Object> eventInfo = event.getEventInfo();
           if (eventInfo == null) {
             continue;

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-applicationhistoryservice/src/test/java/org/apache/hadoop/yarn/server/applicationhistoryservice/TestApplicationHistoryManagerOnTimelineStore.java

@@ -551,23 +551,27 @@ public class TestApplicationHistoryManagerOnTimelineStore {
     entity.addEvent(tEvent);
     if (enableUpdateEvent) {
       tEvent = new TimelineEvent();
-      createAppModifiedEvent(appId, tEvent, "changed queue", 5);
+      long updatedTimeIndex = 4L;
+      createAppModifiedEvent(appId, tEvent, updatedTimeIndex++, "changed queue",
+          5);
       entity.addEvent(tEvent);
       // Change priority alone
       tEvent = new TimelineEvent();
-      createAppModifiedEvent(appId, tEvent, "changed queue", 6);
+      createAppModifiedEvent(appId, tEvent, updatedTimeIndex++, "changed queue",
+          6);
       // Now change queue
       tEvent = new TimelineEvent();
-      createAppModifiedEvent(appId, tEvent, "changed queue1", 6);
+      createAppModifiedEvent(appId, tEvent, updatedTimeIndex++,
+          "changed queue1", 6);
       entity.addEvent(tEvent);
     }
     return entity;
   }
 
   private static void createAppModifiedEvent(ApplicationId appId,
-      TimelineEvent tEvent, String queue, int priority) {
+      TimelineEvent tEvent, long updatedTimeIndex, String queue, int priority) {
     tEvent.setEventType(ApplicationMetricsConstants.UPDATED_EVENT_TYPE);
-    tEvent.setTimestamp(Integer.MAX_VALUE + 4L + appId.getId());
+    tEvent.setTimestamp(Integer.MAX_VALUE + updatedTimeIndex + appId.getId());
     Map<String, Object> eventInfo = new HashMap<String, Object>();
     eventInfo.put(ApplicationMetricsConstants.QUEUE_ENTITY_INFO, queue);
     eventInfo.put(ApplicationMetricsConstants.APPLICATION_PRIORITY_INFO,

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/rmapp/RMAppImpl.java

@@ -1061,7 +1061,7 @@ public class RMAppImpl implements RMApp, Recoverable {
       }
 
       app.rmContext.getSystemMetricsPublisher().appUpdated(app,
-          System.currentTimeMillis());
+          app.systemClock.getTime());
 
       // TODO: Write out change to state store (YARN-1558)
       // Also take care of RM failover