[GitHub] [arrow-rs] crepererum opened a new issue #306: All-null column get wrong parquet null-counts

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

crepererum opened a new issue #306:
URL: https://github.com/apache/arrow-rs/issues/306


   **Describe the bug**
   When serializing an all-null arrow array to parquet, the null-count in the stats is always 0.
   
   **To Reproduce**
   Steps to reproduce the behavior:
   
   ```rust
   #[test]
   fn statistics_null_counts_only_nulls() {
       // check that null-count statistics for "only NULL"-columns are correct
       let values = Arc::new(UInt64Array::from(vec![
           None,
           None,
       ]));
       let file = one_column_roundtrip("null_counts", values, true);
   
       // check statistics are valid
       let reader = SerializedFileReader::new(file).unwrap();
       let metadata = reader.metadata();
       assert_eq!(metadata.num_row_groups(), 1);
       let row_group = metadata.row_group(0);
       assert_eq!(row_group.num_columns(), 1);
       let column = row_group.column(0);
       let stats = column.statistics().unwrap();
       assert_eq!(stats.null_count(), 2);  // <<< this fails, null count is 0
   }
   ```
   
   **Expected behavior**
   For all-null columns the null-count should be the same as the number of rows.
   
   **Additional context**
   Tested on `c863a2c44bffa5c092a49e07910d5e9225483193`.
   
   **I am claiming this issue since I have a fix ready.**
   


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[GitHub] [arrow-rs] sunchao closed issue #306: All-null column get wrong parquet null-counts

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

sunchao closed issue #306:
URL: https://github.com/apache/arrow-rs/issues/306


   


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