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From "Zheng Shao (JIRA)" <j...@apache.org>
Subject [jira] Created: (HIVE-284) Column pruning after join+group-by query
Date Mon, 09 Feb 2009 23:33:59 GMT
Column pruning after join+group-by query
----------------------------------------

                 Key: HIVE-284
                 URL: https://issues.apache.org/jira/browse/HIVE-284
             Project: Hadoop Hive
          Issue Type: Improvement
    Affects Versions: 0.2.0, 0.3.0
            Reporter: Zheng Shao


The query is:

explain INSERT OVERWRITE TABLE t
    SELECT t1.r, t2.c, sum(t1.v * t2.v)
    FROM t1 join t2 on t1.c = t2.r
GROUP BY t1.r, t2.c;

The FileSinkOperator after the join is serializing all 6 columns from the 2 tables (both have
3 columns: r, c, v) instead of the 4 that is needed later.


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