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Posted to dev@hbase.apache.org by "Jean-Marc Spaggiari (JIRA)" <ji...@apache.org> on 2014/07/22 05:39:38 UTC

[jira] [Created] (HBASE-11562) CopyTable should provide an option to shuffle the mapper tasks

Jean-Marc Spaggiari created HBASE-11562:
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             Summary: CopyTable should provide an option to shuffle the mapper tasks
                 Key: HBASE-11562
                 URL: https://issues.apache.org/jira/browse/HBASE-11562
             Project: HBase
          Issue Type: Bug
          Components: mapreduce
    Affects Versions: 0.99.0
            Reporter: Jean-Marc Spaggiari
            Assignee: Jean-Marc Spaggiari


When doing a copy table from a table with a lot of regions to a table to way less regions, on a cluster with limited number of mappers, since map tasks are ordered by key, tasks will first run for the few first regions and will hotspot a single region server on the destination side.

To avoid this, we should submit the map tasks in a random order.

This JIRA is to add this option to CopyTable and TableInputFormat



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