Adds support for Dictionary statistics from parquet data pages. (apache#11195)

Co-authored-by: Eric Fredine <[email protected]>

Author: efredine

datafusion/core/src/datasource/physical_plan/parquet/statistics.rs

@@ -846,6 +846,9 @@ macro_rules! get_data_page_statistics {
                     })
                     }).flatten().collect::<Vec<_>>(),
                 ))),
+                Some(DataType::Dictionary(_, value_type)) => {
+                    [<$stat_type_prefix:lower _ page_statistics>](Some(value_type), $iterator)
+                },
                 Some(DataType::Timestamp(unit, timezone)) => {
                     let iter = [<$stat_type_prefix Int64DataPageStatsIterator>]::new($iterator).flatten();
                     Ok(match unit {

datafusion/core/tests/parquet/arrow_statistics.rs

@@ -1752,7 +1752,7 @@ async fn test_dictionary() {
         expected_null_counts: UInt64Array::from(vec![1, 0]),
         expected_row_counts: Some(UInt64Array::from(vec![5, 2])),
         column_name: "string_dict_i32",
-        check: Check::RowGroup,
+        check: Check::Both,
     }
     .run();