[jira] Created: (HADOOP-2639) Reducers stuck in shuffle

Reducers stuck in shuffle
-------------------------

                 Key: HADOOP-2639
                 URL: https://issues.apache.org/jira/browse/HADOOP-2639
             Project: Hadoop
          Issue Type: Bug
            Reporter: Amareshwari Sri Ramadasu
            Priority: Critical
             Fix For: 0.16.0



I started sort benchmark on 500 nodes. It has 40000 maps and 900 reducers.
There are 11 reducers stuck in shuffle with 33% progress. I could see a node down which ran 80 maps on it. And all these reducers are trying to fetch map output from that node.

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     [ https://issues.apache.org/jira/browse/HADOOP-2639?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Devaraj Das updated HADOOP-2639:
--------------------------------

       Assignee: Amar Kamat
       Priority: Blocker  (was: Critical)
    Description:
I started sort benchmark on 500 nodes. It has 40000 maps and 900 reducers.
There are 11 reducers stuck in shuffle with 33% progress. I could see a node down which ran 80 maps on it. And all these reducers are trying to fetch map output from that node.

  was:

I started sort benchmark on 500 nodes. It has 40000 maps and 900 reducers.
There are 11 reducers stuck in shuffle with 33% progress. I could see a node down which ran 80 maps on it. And all these reducers are trying to fetch map output from that node.

> Reducers stuck in shuffle
> -------------------------
>
>                 Key: HADOOP-2639
>                 URL: https://issues.apache.org/jira/browse/HADOOP-2639
>             Project: Hadoop
>          Issue Type: Bug
>            Reporter: Amareshwari Sri Ramadasu
>            Assignee: Amar Kamat
>            Priority: Blocker
>             Fix For: 0.16.0
>
>
> I started sort benchmark on 500 nodes. It has 40000 maps and 900 reducers.
> There are 11 reducers stuck in shuffle with 33% progress. I could see a node down which ran 80 maps on it. And all these reducers are trying to fetch map output from that node.

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    [ https://issues.apache.org/jira/browse/HADOOP-2639?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12560925#action_12560925 ]

Amar Kamat commented on HADOOP-2639:
------------------------------------

I ran sort-100 with a bunch of maps not serving output to a bunch of reducers, here 10 maps blocking 5 reducers. The job ran to completion. I am not able to reproduce the error.  Is there a way to reproduce the error.

> Reducers stuck in shuffle
> -------------------------
>
>                 Key: HADOOP-2639
>                 URL: https://issues.apache.org/jira/browse/HADOOP-2639
>             Project: Hadoop
>          Issue Type: Bug
>            Reporter: Amareshwari Sri Ramadasu
>            Assignee: Amar Kamat
>            Priority: Blocker
>             Fix For: 0.16.0
>
>
> I started sort benchmark on 500 nodes. It has 40000 maps and 900 reducers.
> There are 11 reducers stuck in shuffle with 33% progress. I could see a node down which ran 80 maps on it. And all these reducers are trying to fetch map output from that node.

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     [ https://issues.apache.org/jira/browse/HADOOP-2639?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Sameer Paranjpye updated HADOOP-2639:
-------------------------------------

    Component/s: mapred

> Reducers stuck in shuffle
> -------------------------
>
>                 Key: HADOOP-2639
>                 URL: https://issues.apache.org/jira/browse/HADOOP-2639
>             Project: Hadoop
>          Issue Type: Bug
>          Components: mapred
>            Reporter: Amareshwari Sri Ramadasu
>            Assignee: Amar Kamat
>            Priority: Blocker
>             Fix For: 0.16.0
>
>
> I started sort benchmark on 500 nodes. It has 40000 maps and 900 reducers.
> There are 11 reducers stuck in shuffle with 33% progress. I could see a node down which ran 80 maps on it. And all these reducers are trying to fetch map output from that node.

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