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https://issues.apache.org/jira/browse/MAPREDUCE-3921?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13248512#comment-13248512
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Bikas Saha commented on MAPREDUCE-3921:
---------------------------------------
1) By AM Recovery do you mean recovery after restart? The test added in this
patch check that the AM restarts a previously successful task when the node (on
which it ran) goes bad. See TestMRApp.java.
2) My understanding was that the new version of the map is a pre-emptively
created copy. The running reduces would use their existing inputs. Is that not
the case? Are reducers informed about new locations for map outputs on the fly?
4)6) The comments are for reviewers to clarify those points. eg. Some of the
code was taken from similar actions elsewhere. They set the finish time and I
was not sure if that was the correct thing to do. I dont think the assert is
necessary given the current code but do you usually put in asserts?
5) The log means that this task was not started and hence further history
events are not being added. This is similar to other places in the code
> MR AM should act on the nodes liveliness information when nodes go
> up/down/unhealthy
> ------------------------------------------------------------------------------------
>
> Key: MAPREDUCE-3921
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-3921
> Project: Hadoop Map/Reduce
> Issue Type: Bug
> Components: mr-am, mrv2
> Affects Versions: 0.23.0
> Reporter: Vinod Kumar Vavilapalli
> Assignee: Bikas Saha
> Fix For: 0.23.2
>
> Attachments: MAPREDUCE-3921-branch-0.23.patch,
> MAPREDUCE-3921-branch-0.23.patch, MAPREDUCE-3921-branch-0.23.patch,
> MAPREDUCE-3921.patch
>
>
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