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From "Ruslan Dautkhanov (JIRA)" <j...@apache.org>
Subject [jira] [Created] (HIVE-13076) Implement FK/PK "rely novalidate" constraints for better CBO
Date Wed, 17 Feb 2016 17:35:18 GMT
Ruslan Dautkhanov created HIVE-13076:
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             Summary: Implement FK/PK "rely novalidate" constraints for better CBO
                 Key: HIVE-13076
                 URL: https://issues.apache.org/jira/browse/HIVE-13076
             Project: Hive
          Issue Type: Improvement
          Components: CBO, Logical Optimizer
            Reporter: Ruslan Dautkhanov


Oracle has "RELY NOVALIDATE" option for constraints.. Could be easier for Hive to start with
something like that for PK/FK constraints. So CBO has more information for optimizations.
It does not have to actually check if that constraint is relationship is true; it can just
"rely" on that constraint.. 

https://docs.oracle.com/database/121/SQLRF/clauses002.htm#sthref2289

So it would be helpful with join cardinality estimates, and with cases like this - https://issues.apache.org/jira/browse/HIVE-13019



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