[
https://issues.apache.org/jira/browse/MAPREDUCE-4752?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13488713#comment-13488713
]
Thomas Graves commented on MAPREDUCE-4752:
------------------------------------------
created HADOOP-9003 for tracking common change
> Reduce MR AM memory usage through String Interning
> --------------------------------------------------
>
> Key: MAPREDUCE-4752
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-4752
> Project: Hadoop Map/Reduce
> Issue Type: Improvement
> Components: mrv2
> Reporter: Robert Joseph Evans
> Assignee: Robert Joseph Evans
> Fix For: 3.0.0, 2.0.3-alpha, 0.23.5
>
> Attachments: MR-4752-branch-0.23.txt, MR-4752-branch-0.23.txt,
> MR-4752-trunk.txt, MR-4752-trunk.txt
>
>
> There are a lot of strings that are duplicates of one another in the AM.
> This comes from all of the PB events the come across the wire and also tasks
> heart-beating in through the umbilical. There are even several duplicates
> from Configuration. By "interning" all of these strings on the Heap I have
> been able to reduce the resting memory usage of the AM to be about 5KB per
> task attempt. With about half of this coming from counters. This results in
> a 5MB heap for a typical 1000 task job, or a 500MB heap for a 100,000 task
> attempt job. I think I could cut the size of the counters in half by
> completely rewriting how counters work in the AM and History Server, but I
> don't think it is worth it at this point.
> I am still investigating what the memory usage of the AM is like when running
> very large jobs, and I will probably have a follow-up JIRA for reducing that
> memory usage as well.
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira
