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https://issues.apache.org/jira/browse/TRAFODION-25?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14945405#comment-14945405
]
ASF GitHub Bot commented on TRAFODION-25:
-----------------------------------------
Github user DaveBirdsall commented on a diff in the pull request:
https://github.com/apache/incubator-trafodion/pull/102#discussion_r41294860
--- Diff: core/sql/optimizer/CostMethod.h ---
@@ -2036,30 +2037,31 @@ class CostMethodHbaseInsert : public CostMethod
//<pb>
/**********************************************************************/
/* */
-/* CostMethodDP2UpdateOrDelete */
+/* CostMethodHbaseUpdateOrDelete */
/* */
/**********************************************************************/
-class CostMethodDP2UpdateOrDelete : public CostMethod
+class CostMethodHbaseUpdateOrDelete : public CostMethod
{
public:
// Constructor
- CostMethodDP2UpdateOrDelete( const char* className )
+ CostMethodHbaseUpdateOrDelete( const char* className )
: CostMethod( className )
{};
protected:
- // Cost functions
+ // Old model cost function (obsolete; only here because base
+ // class requires an implementation)
virtual Cost* computeOperatorCostInternal(RelExpr* op,
const Context* myContext,
- Lng32& countOfStreams) = 0;
+ Lng32& countOfStreams);
+
// SCM Cost function
virtual Cost* scmComputeOperatorCostInternal(RelExpr* op,
- const Context* myContext,
const PlanWorkSpace* pws,
Lng32& countOfStreams) = 0;
- // Common functions to cost DP2 operations.
+ // Common functions to cost Hbase operations.
--- End diff --
Will try to wordsmith this comment in a more meaningful way.
> Insert, delete and update operators should use specialized cost method
> -----------------------------------------------------------------------
>
> Key: TRAFODION-25
> URL: https://issues.apache.org/jira/browse/TRAFODION-25
> Project: Apache Trafodion
> Issue Type: Bug
> Reporter: Qifan Chen
> Assignee: David Wayne Birdsall
> Labels: performance
>
> In Trafodion, insert, delete and update operators do not use a specialized
> cost method that model the true operation involved.
> As a result, these operators can be assigned a zero cost and the query plan
> may not be optimal. In one example, a delete query against a partitioned
> table may get a serial plan.
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