[jira] [Created] (TRAFODION-2827) Turn CQD HBASE_UPDATE_COSTING 'ON' by default

["David Wayne Birdsall (JIRA)" <ji...@apache.org>]

David Wayne Birdsall created TRAFODION-2827:
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             Summary: Turn CQD HBASE_UPDATE_COSTING 'ON' by default
                 Key: TRAFODION-2827
                 URL: https://issues.apache.org/jira/browse/TRAFODION-2827
             Project: Apache Trafodion
          Issue Type: Improvement
          Components: sql-cmp
            Reporter: David Wayne Birdsall
            Assignee: David Wayne Birdsall


There are presently two sets of stubbed costing code for HBase updates in the Optimizer. The original set simply gives a zero cost to any update node. This is the original stub, and is the one executed by default. The second stub is a copy of the delete costing code, and is executed if CQD HBASE_UPDATE_COSTING is 'ON'. This is much better, because it at least assigns non-zero costs to update nodes. One can get parallel plans for larger update statements using this code, while all plans for the original stub are serial. It isn't perfect, because the theory of operation for update is a bit different than delete, but it should be much better for all but the most trivial update statements.

As we are beginning to see applications using Trafodion that have larger update statements, it makes sense to change the default for CQD HBASE_UPDATE_COSTING to 'ON' now.




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