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https://issues.apache.org/jira/browse/CALCITE-4223?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17191432#comment-17191432
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Danny Chen commented on CALCITE-4223:
-------------------------------------

I want to share the usage of Apache Flink, we sub-class the {{Statistic}}, 
there is a structure named {{FlinkStatistic}}, the {{FlinkStatistic}} keep an 
optional member named {{TableStats}}, the {{TableStats}} has {{ColumnStats}} 
for each column.

> Introducing column statistics to RelOptTable
> --------------------------------------------
>
>                 Key: CALCITE-4223
>                 URL: https://issues.apache.org/jira/browse/CALCITE-4223
>             Project: Calcite
>          Issue Type: Improvement
>            Reporter: Chunwei Lei
>            Assignee: Chunwei Lei
>            Priority: Major
>
> Many systems depend on column statistics to compute more accurate stats, such 
> as NDV, average column size, and so on. It would be nice if Calcite can 
> provide such an interface.
> Column statistics might include NDV, average/max column length, number of 
> nulls, number of trues, number of falses and so on. 
> What do you think?
>  



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