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Vinod Kumar Vavilapalli commented on MAPREDUCE-4752:
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Can you open a ticket in common regarding the Configuration changes and close that as a duplicate
of this. Just so that folks know. Wherever possible, you should create separate tickets for
changes that span the sub-projects. Tx.
bq. 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.
Please post your ideas, we can see if it is achievable in bits and pieces.
> 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.
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