[
https://issues.apache.org/jira/browse/MAPREDUCE-3274?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13137253#comment-13137253
]
Robert Joseph Evans commented on MAPREDUCE-3274:
------------------------------------------------
I agree that is the way to go. I will start working on a patch. FYI
TaskAttempListenerImpl.getTaskJVM has 3 TODOs in it.
{code}
// TODO: Is it an authorised container to get a task? Otherwise return null.
// TODO: Is the request for task-launch still valid?
// TODO: Child.java's firstTaskID isn't really firstTaskID. Ask for update
// to jobId and task-type.
{code}
None of them really seem that related to this, but it will never return a
JvmTask with shouldDie set to true. It just returns null if it does not have
anything for the task to do. Should I change it so that if there is nothing
for the task to do then it should kill the task?
> Race condition in MR App Master Preemtion can cause a dead lock
> ---------------------------------------------------------------
>
> Key: MAPREDUCE-3274
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-3274
> Project: Hadoop Map/Reduce
> Issue Type: Bug
> Components: applicationmaster, mrv2
> Affects Versions: 0.23.0, 0.24.0
> Reporter: Robert Joseph Evans
> Assignee: Robert Joseph Evans
> Priority: Blocker
> Fix For: 0.23.0, 0.24.0
>
>
> There appears to be a race condition in the MR App Master in relation to
> preempting reducers to let a mapper run. In the particular case that I have
> been debugging a reducer was selected for preemption that did not have a
> container assigned to it yet. When the container became available that reduce
> started running and the previous TA_KILL event appears to have been ignored.
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators:
https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa
For more information on JIRA, see: http://www.atlassian.com/software/jira
