Namit Jain created HIVE-4006:
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             Summary: Add local sort operator
                 Key: HIVE-4006
                 URL: https://issues.apache.org/jira/browse/HIVE-4006
             Project: Hive
          Issue Type: New Feature
          Components: Query Processor
            Reporter: Namit Jain
            Assignee: Namit Jain


We've seen in the past that sorting data on a specific column can greatly 
improve the compression of data.  The problem is that sorting data is expensive 
and requires a reduce phase.

One way around this is to add a local sort (either as an operator or between 
serialization and output).  This could take chunks of rows and do an in memory 
sort of these.  This would be much faster, but would need to be very memory 
efficient in order to get the maximum number of rows in a chunk (and hence the 
maximum benefit).

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