[jira] [Created] (TRAFODION-1987) Enable min/max optimization for TYPE 1 repartitioned joins

["Hans Zeller (JIRA)" <ji...@apache.org>]

Hans Zeller created TRAFODION-1987:
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             Summary: Enable min/max optimization for TYPE 1 repartitioned joins
                 Key: TRAFODION-1987
                 URL: https://issues.apache.org/jira/browse/TRAFODION-1987
             Project: Apache Trafodion
          Issue Type: Improvement
          Components: sql-cmp
    Affects Versions: 1.3-incubating
            Reporter: Hans Zeller
            Assignee: Hans Zeller
             Fix For: 2.1-incubating


Right now, min/max optimization for hash joins (making min and max values of equi-join columns available to the outer child tree of a hash join) is limited to operators in the same plan fragment. In other words, an ESP_EXCHANGE between a scan and a hash join makes it impossible to do this optimization. We could be a bit less restrictive: If the hash table of the hash join isn't partitioned, either because it runs in a single instance, or because its right (inner) child is replicated, then we can do this optimization across exchanges.



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