[jira] [Created] (HBASE-15660) Printing extra refs in ITBLL.Verify reducer can cause reducers to be killed due to lack of progress

["Josh Elser (JIRA)" <ji...@apache.org>]

Josh Elser created HBASE-15660:
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             Summary: 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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