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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