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https://issues.apache.org/jira/browse/TRAFODION-3050?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16460100#comment-16460100
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ASF GitHub Bot commented on TRAFODION-3050:
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Github user asfgit closed the pull request at:
https://github.com/apache/trafodion/pull/1546
> Inefficient plan when joining on VARCHAR columns
> ------------------------------------------------
>
> Key: TRAFODION-3050
> URL: https://issues.apache.org/jira/browse/TRAFODION-3050
> Project: Apache Trafodion
> Issue Type: Bug
> Components: sql-cmp
> Affects Versions: 2.3
> Reporter: David Wayne Birdsall
> Assignee: David Wayne Birdsall
> Priority: Major
> Attachments: JiraVarchar.log, JiraVarchar.sql
>
>
> This is follow-on work to Jira TRAFODION-3031. That Jira fixed some issues
> with plan choice when joining on integer columns.
> In this particular example, the join is on VARCHAR columns. With the fix from
> Jira TRAFODION-3031, we get a nice nested join plan for the subqueries, but
> still get a hash join at the top, which is inefficient in this example.
> The attached script reproduces the problem and demonstrates a work-around.
> When CQD COMP_BOOL_158 is set to 'ON', we get a good plan. The attached log
> shows the script results.
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