[
https://issues.apache.org/jira/browse/MAPREDUCE-1220?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Greg Roelofs updated MAPREDUCE-1220:
------------------------------------
Attachment: MR-1220.v1b.sshot-02-jobdetails.jsp.png
screenshot of jobdetails page (uber-job still running)
The "Job Scheduling information" line shows up again here, but the top table is
also modified, as is the title of the graph. Trivial stuff, but it provides a
clue to the user in case the optimization is less transparent than intended.
> Implement an in-cluster LocalJobRunner
> --------------------------------------
>
> Key: MAPREDUCE-1220
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-1220
> Project: Hadoop Map/Reduce
> Issue Type: New Feature
> Components: client, jobtracker
> Reporter: Arun C Murthy
> Assignee: Greg Roelofs
> Attachments: MAPREDUCE-1220_yhadoop20.patch,
> MR-1220.v1.trunk-hadoop-common.Progress-dumper.patch.txt,
> MR-1220.v10e-v11c-v12b.ytrunk-hadoop-mapreduce.delta.patch.txt,
> MR-1220.v13.ytrunk-hadoop-mapreduce.delta.patch.txt,
> MR-1220.v14b.ytrunk-hadoop-mapreduce.delta.patch.txt,
> MR-1220.v15.ytrunk-hadoop-mapreduce.delta.patch.txt,
> MR-1220.v1b.sshot-02-jobdetails.jsp.png,
> MR-1220.v2.trunk-hadoop-mapreduce.patch.txt,
> MR-1220.v2.trunk-hadoop-mapreduce.patch.txt,
> MR-1220.v2b.sshot-01-jobtracker.jsp.png,
> MR-1220.v6.ytrunk-hadoop-mapreduce.patch.txt,
> MR-1220.v7.ytrunk-hadoop-mapreduce.delta.patch.txt,
> MR-1220.v8b.ytrunk-hadoop-mapreduce.delta.patch.txt,
> MR-1220.v9c.ytrunk-hadoop-mapreduce.delta.patch.txt
>
>
> Currently very small map-reduce jobs suffer from latency issues due to
> overheads in Hadoop Map-Reduce such as scheduling, jvm startup etc. We've
> periodically tried to optimize all parts of framework to achieve lower
> latencies.
> I'd like to turn the problem around a little bit. I propose we allow very
> small jobs to run as a single task job with multiple maps and reduces i.e.
> similar to our current implementation of the LocalJobRunner. Thus, under
> certain conditions (maybe user-set configuration, or if input data is small
> i.e. less a DFS blocksize) we could launch a special task which will run all
> maps in a serial manner, followed by the reduces. This would really help
> small jobs achieve significantly smaller latencies, thanks to lesser
> scheduling overhead, jvm startup, lack of shuffle over the network etc.
> This would be a huge benefit, especially on large clusters, to small Hive/Pig
> queries.
> Thoughts?
--
This message is automatically generated by JIRA.
For more information on JIRA, see: http://www.atlassian.com/software/jira
