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From "Namit Jain (JIRA)" <j...@apache.org>
Subject [jira] Created: (HADOOP-4157) [hive] redundant expression evaluation in group by stage 1
Date Thu, 11 Sep 2008 01:34:44 GMT
[hive] redundant expression evaluation in group by stage 1

                 Key: HADOOP-4157
                 URL: https://issues.apache.org/jira/browse/HADOOP-4157
             Project: Hadoop Core
          Issue Type: Bug
          Components: contrib/hive
            Reporter: Namit Jain

We can be smarter in terms of this list of what parameters we evaluate in the first stage,
we should only evaluate those that are common across the group by clauses.

All expressions and aggregation function parameters are evaluated in the first stage thereby
increasing data flow. It might be better to only evaluate common expressions

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