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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