[jira] [Updated] (ARROW-10781) [Rust] [DataFusion] TableProvider should provide row count statistics

["ASF GitHub Bot (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/ARROW-10781?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

ASF GitHub Bot updated ARROW-10781:
-----------------------------------
    Labels: pull-request-available  (was: )

> [Rust] [DataFusion] TableProvider should provide row count statistics
> ---------------------------------------------------------------------
>
>                 Key: ARROW-10781
>                 URL: https://issues.apache.org/jira/browse/ARROW-10781
>             Project: Apache Arrow
>          Issue Type: New Feature
>          Components: Rust - DataFusion
>            Reporter: Andy Grove
>            Priority: Major
>              Labels: pull-request-available
>          Time Spent: 10m
>  Remaining Estimate: 0h
>
> In order to start building a cost-based optimizer, we need some statistics about data sources. The most basic statistic would be number of rows.
> I propose that we add a Statistics struct that initially just makes a total row count available but that we can later extend to support more advanced statistics.
> {code:java}
> struct Statistics {
>   row_count: Option<usize>
> } {code}
> We can then add a method to TableProvider:
> {code:java}
> trait TableProvider {
>   fn statistics() -> Option<Statistics>;
> } {code}
> Statistics should be optional because not all data sources can provide statistics.



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