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https://issues.apache.org/jira/browse/FLINK-16195?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Flink Jira Bot updated FLINK-16195:
-----------------------------------
    Labels: stale-assigned  (was: )

> Append constant fields to unique key set when deriving unique keys in 
> FlinkRelMdUniqueKeys on project
> -----------------------------------------------------------------------------------------------------
>
>                 Key: FLINK-16195
>                 URL: https://issues.apache.org/jira/browse/FLINK-16195
>             Project: Flink
>          Issue Type: Improvement
>          Components: Table SQL / Planner
>            Reporter: godfrey he
>            Assignee: godfrey he
>            Priority: Major
>              Labels: stale-assigned
>
> currently, {{FlinkRelMdUniqueKeys}} only supports deriving unique keys on 
> non-constant fields. such as: {{select a, b, 1, count( * ) from T group by a, 
> b}}, currently the derived unique keys is {{a, b}}. However {{a, b, 1}} is 
> also a unique key, and the result is {{a, b}} and {{a, b, 1}}.
> note: Ideally, the planner does not require the constant key in the unique 
> key set, all constant values are pulled up or removed as much as possible. 
> Supports this improvement to handle some corner cases in cbo.



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