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https://issues.apache.org/jira/browse/HBASE-15660?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15243208#comment-15243208
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Josh Elser commented on HBASE-15660:
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The change is dirt simple, but I need to rerun with it just to make sure that
it's working as I expect it should.
> Printing extra refs in ITBLL.Verify reducer can cause reducers to be killed
> due to lack of progress
> ---------------------------------------------------------------------------------------------------
>
> Key: HBASE-15660
> URL: https://issues.apache.org/jira/browse/HBASE-15660
> Project: HBase
> Issue Type: Bug
> Components: integration tests
> Reporter: Josh Elser
> Assignee: Josh Elser
> Priority: Minor
> Fix For: 2.0.0, 1.1.5, 1.2.2
>
>
> In debugging an ITBLL job which has numerous failures, I saw that instead of
> the Verify job completing and reporting that there were a large number of
> UNDEF nodes, the reducers in the Verify were failing due to lack of progress.
> The reducer's syslog file was filled with information from the
> {{dumpExtraInfoOnRefs()}} method. I believe that when a reducer is repeatedly
> doing these lookups, the MR framework doesn't realize that any progress is
> being made (nothing is being written to the context) and eventually kills the
> reducer task. This ultimately causes the entire Verify job to fail because
> the reducer fails in the same manner each time.
> We should make sure to invoke {{context.progress()}} when we do these lookups
> to let the framework know that we're still doing "our thing".
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