[
https://issues.apache.org/jira/browse/TRAFODION-2827?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
David Wayne Birdsall closed TRAFODION-2827.
-------------------------------------------
> 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
> Priority: Major
> Fix For: 2.3
>
>
> 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.
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
