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https://issues.apache.org/jira/browse/MAPREDUCE-327?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14070734#comment-14070734
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Allen Wittenauer commented on MAPREDUCE-327:
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In real-world scenarios, we've discovered that task locality as reported by the
system can effectively be a lie because of CFIF/MFIF. Given 4 input splits, if
the first is local but the rest are not, the task will still be considered
local even though 3/4'ths of the data came off rack!
> Add explicit remote map count JobTracker metrics
> ------------------------------------------------
>
> Key: MAPREDUCE-327
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-327
> Project: Hadoop Map/Reduce
> Issue Type: Improvement
> Reporter: Hong Tang
> Labels: newbie
>
> I am proposing to add a counter REMOTE_MAPS in addition to the following
> counters: TOTAL_MAPS, DATA_LOCAL_MAPS, RACK_LOCAL_MAPS. A Map Task is
> considered a "remote-map" iff the input split returns a set of locations, but
> none is chosen to execute the map task.
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