[teiid-issues] [JBoss JIRA] (TEIID-4332) Enhance costing to better guess at ndv

[Steven Hawkins (JIRA)]

     [ https://issues.jboss.org/browse/TEIID-4332?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Steven Hawkins resolved TEIID-4332.
-----------------------------------
    Resolution: Done


Updated the costing to more consistently deal with the ndv and to infer it's value in more situations.  Added a release note to warn that plans could be different than before.

Did not yet flip the default behavior for aggressiveJoinGrouping, but it does appear that we'll plan more appropriately in that scenario even with just cardinality and key information.

> Enhance costing to better guess at ndv
> --------------------------------------
>
>                 Key: TEIID-4332
>                 URL: https://issues.jboss.org/browse/TEIID-4332
>             Project: Teiid
>          Issue Type: Quality Risk
>          Components: Query Engine
>            Reporter: Steven Hawkins
>            Assignee: Steven Hawkins
>             Fix For: 9.1
>
>
> Our logic for determining ndv is mostly ad hoc and varies greatly depending upon the position in the plan.  This needs to be more standardized and based upon consistent assumptions - also additional information such as predicates and foreign keys should influence the calculation.



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