fix panic in ParquetMetadata::memory_size: check has_min_max_set be…

…fore invoking min()/max() (#6092)

* fix: check has_min_max_set before invoking min()/max()

* chore: add unit test for statistics heap size

* Fixup test

---------

Co-authored-by: Andrew Lamb <andrew@nerdnetworks.org>

parquet/src/file/metadata/memory.rs

@@ -173,7 +173,14 @@ impl<T: ParquetValueType> HeapSize for PageIndex<T> {
 
 impl<T: ParquetValueType> HeapSize for ValueStatistics<T> {
     fn heap_size(&self) -> usize {
-        self.min().heap_size() + self.max().heap_size()
+        if self.has_min_max_set() {
+            return self.min().heap_size() + self.max().heap_size();
+        } else if self.min_is_exact() {
+            return self.min().heap_size();
+        } else if self.max_is_exact() {
+            return self.max().heap_size();
+        }
+        0
     }
 }
 impl HeapSize for bool {

parquet/src/file/metadata/mod.rs

@@ -1291,7 +1291,11 @@ mod tests {
         let columns = schema_descr
             .columns()
             .iter()
-            .map(|column_descr| ColumnChunkMetaData::builder(column_descr.clone()).build())
+            .map(|column_descr| {
+                ColumnChunkMetaData::builder(column_descr.clone())
+                    .set_statistics(Statistics::new::<i32>(None, None, None, 0, false))
+                    .build()
+            })
             .collect::<Result<Vec<_>>>()
             .unwrap();
         let row_group_meta = RowGroupMetaData::builder(schema_descr.clone())
@@ -1317,11 +1321,31 @@ mod tests {
             num_rows,
             created_by,
             key_value_metadata,
-            schema_descr,
+            schema_descr.clone(),
             column_orders,
         );
-        let parquet_meta = ParquetMetaData::new(file_metadata.clone(), row_group_meta.clone());
-        let base_expected_size = 1320;
+
+        // Now, add in Exact Statistics
+        let columns_with_stats = schema_descr
+            .columns()
+            .iter()
+            .map(|column_descr| {
+                ColumnChunkMetaData::builder(column_descr.clone())
+                    .set_statistics(Statistics::new::<i32>(Some(0), Some(100), None, 0, false))
+                    .build()
+            })
+            .collect::<Result<Vec<_>>>()
+            .unwrap();
+
+        let row_group_meta_with_stats = RowGroupMetaData::builder(schema_descr)
+            .set_num_rows(1000)
+            .set_column_metadata(columns_with_stats)
+            .build()
+            .unwrap();
+        let row_group_meta_with_stats = vec![row_group_meta_with_stats];
+
+        let parquet_meta = ParquetMetaData::new(file_metadata.clone(), row_group_meta_with_stats);
+        let base_expected_size = 2024;
         assert_eq!(parquet_meta.memory_size(), base_expected_size);
 
         let mut column_index = ColumnIndexBuilder::new();