[
https://issues.apache.org/jira/browse/MAPREDUCE-4502?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13464306#comment-13464306
]
Chris Douglas commented on MAPREDUCE-4502:
------------------------------------------
Thanks, Karthik; that was the tech report I meant to link to earlier (off by
one error): http://research.yahoo.com/files/yl-2012-002.pdf
> Multi-level aggregation with combining the result of maps per node/rack
> -----------------------------------------------------------------------
>
> Key: MAPREDUCE-4502
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-4502
> Project: Hadoop Map/Reduce
> Issue Type: Improvement
> Components: applicationmaster, mrv2
> Reporter: Tsuyoshi OZAWA
> Assignee: Tsuyoshi OZAWA
> Attachments: design_v2.pdf, speculative_draft.pdf
>
>
> The shuffle costs is expensive in Hadoop in spite of the existence of
> combiner, because the scope of combining is limited within only one MapTask.
> To solve this problem, it's a good way to aggregate the result of maps per
> node/rack by launch combiner.
> This JIRA is to implement the multi-level aggregation infrastructure,
> including combining per container(MAPREDUCE-3902 is related), coordinating
> containers by application master without breaking fault tolerance of jobs.
--
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
