[GitHub] [arrow] alamb commented on a change in pull request #8998: ARROW-11018: [Rust][DataFusion] Add support for column-level statistics, null count.

[GitBox <gi...@apache.org>]

alamb commented on a change in pull request #8998:
URL: https://github.com/apache/arrow/pull/8998#discussion_r549106965



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File path: rust/datafusion/src/datasource/datasource.rs
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@@ -33,6 +33,14 @@ pub struct Statistics {
     pub num_rows: Option<usize>,
     /// total byte of the table rows
     pub total_byte_size: Option<usize>,
+    /// Statistics on a column level
+    pub column_statistics: Option<Vec<ColumnStatistics>>,
+}
+/// This table statistics are estimates about column

Review comment:
       Eventually the use of these statistics is probably more general than just datasources (aka for a cost based optimizer we would probably want the estimates to be attached to the output of all LogicalPlan nodes). 
   
   But this is a good start for now!




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