[
https://issues.apache.org/jira/browse/HADOOP-5374?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12682571#action_12682571
]
Amareshwari Sriramadasu commented on HADOOP-5374:
-------------------------------------------------
There are three threads in JobTracker updating the TaskStatuses :
ExpireTrackers, ExpireLaunchingTasks and heartbeat threads.
1. If heartbeat runs first, there is no issue with ExpireTrackers and
ExpireLaunchingTasks threads, since the entry will removed from them.
2. If ExpireTrackers runs first, there is no issue with heartbeat(The tracker
will be re-inited) and ExpireLaunchingTasks(he task-entry will removed from the
thread).
3. If ExpireLaunchingTasks runs first,
a) If ExpireTrackers runs second, the task attempt will be Killed again.
The task will have FAILED, followed by KILLED update.
b) If heartbeat runs second, If the TaskStatus is UNASSIGNED, RUNNING,
COMMIT_PENDING or SUCCEDED, the task will be added to taskToKill map and the
update is ignored. So, the tasks will be sent KillTaskAction(fixed by
HADOOP-5280). If the state is COMMIT_PENDING, it throws NPE as described in
this jira.
I propose this issue can fix both 3(a) and 3(b).
> NPE in JobTracker.getTasksToSave() method
> -----------------------------------------
>
> Key: HADOOP-5374
> URL: https://issues.apache.org/jira/browse/HADOOP-5374
> Project: Hadoop Core
> Issue Type: Bug
> Components: mapred
> Affects Versions: 0.20.0
> Reporter: Vinod K V
> Assignee: Amareshwari Sriramadasu
> Attachments: patch-5374-1.txt
>
>
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
