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https://issues.apache.org/jira/browse/MAPREDUCE-2216?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Joydeep Sen Sarma updated MAPREDUCE-2216:
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Component/s: jobtracker
hard to believe there's not a jira open for this already - please
close/redirect if that is so.
> speculation should normalize progress rates based on amount of input data
> -------------------------------------------------------------------------
>
> Key: MAPREDUCE-2216
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-2216
> Project: Hadoop Map/Reduce
> Issue Type: Bug
> Components: jobtracker
> Reporter: Joydeep Sen Sarma
>
> We frequently see skews in data distribution both on the mappers and
> reducers. The small ones finish quickly and the longer ones immediately get
> speculated. We should normalize progress rates used by speculation with some
> metric correlated to the amount of data processed by the task (like bytes
> read of rows processed). That will prevent these unnecessary speculations.
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