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https://issues.apache.org/jira/browse/MAPREDUCE-5124?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15229192#comment-15229192
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Haibo Chen commented on MAPREDUCE-5124:
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[~jlowe], [~ozawa], [~revans2] Does increasing the task report interval sound 
like a viable approach to alleviate the issue here? Right now the report 
interval is hardcoded as 3 seconds. 
We could make the task report interval configurable and increase the interval 
with some heuristics to limit the number of task status updates per unit time.

> AM lacks flow control for task events
> -------------------------------------
>
>                 Key: MAPREDUCE-5124
>                 URL: https://issues.apache.org/jira/browse/MAPREDUCE-5124
>             Project: Hadoop Map/Reduce
>          Issue Type: Bug
>          Components: mr-am
>    Affects Versions: 2.0.3-alpha, 0.23.5
>            Reporter: Jason Lowe
>         Attachments: MAPREDUCE-5124-proto.2.txt, MAPREDUCE-5124-prototype.txt
>
>
> The AM does not have any flow control to limit the incoming rate of events 
> from tasks.  If the AM is unable to keep pace with the rate of incoming 
> events for a sufficient period of time then it will eventually exhaust the 
> heap and crash.  MAPREDUCE-5043 addressed a major bottleneck for event 
> processing, but the AM could still get behind if it's starved for CPU and/or 
> handling a very large job with tens of thousands of active tasks.



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