[GitHub] [arrow-rs] nevi-me commented on a change in pull request #258: support full u32 and u64 roundtrip through parquet

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

nevi-me commented on a change in pull request #258:
URL: https://github.com/apache/arrow-rs/pull/258#discussion_r629513251



##########
File path: parquet/src/column/writer.rs
##########
@@ -925,31 +934,51 @@ impl<T: DataType> ColumnWriterImpl<T> {
     fn update_page_min_max(&mut self, val: &T::T) {
         // simple "isNaN" check that works for all types
         if val == val {
-            if self.min_page_value.as_ref().map_or(true, |min| min > val) {
+            if self
+                .min_page_value
+                .as_ref()
+                .map_or(true, |min| self.compare_greater(min, val))
+            {
                 self.min_page_value = Some(val.clone());
             }
-            if self.max_page_value.as_ref().map_or(true, |max| max < val) {
+            if self
+                .max_page_value
+                .as_ref()
+                .map_or(true, |max| self.compare_greater(val, max))
+            {
                 self.max_page_value = Some(val.clone());
             }
         }
     }
 
     fn update_column_min_max(&mut self) {
-        if self
-            .min_column_value
-            .as_ref()
-            .map_or(true, |min| min > self.min_page_value.as_ref().unwrap())
-        {
+        let update_min = self.min_column_value.as_ref().map_or(true, |min| {
+            let page_value = self.min_page_value.as_ref().unwrap();
+            self.compare_greater(min, page_value)
+        });
+        if update_min {
             self.min_column_value = self.min_page_value.clone();
         }
-        if self
-            .max_column_value
-            .as_ref()
-            .map_or(true, |max| max < self.max_page_value.as_ref().unwrap())
-        {
+
+        let update_max = self.max_column_value.as_ref().map_or(true, |max| {
+            let page_value = self.max_page_value.as_ref().unwrap();
+            self.compare_greater(page_value, max)
+        });
+        if update_max {
             self.max_column_value = self.max_page_value.clone();
         }
     }
+
+    /// Evaluate `a > b` according to underlying logical type.
+    fn compare_greater(&self, a: &T::T, b: &T::T) -> bool {
+        if let Some(LogicalType::INTEGER(int_type)) = self.descr.logical_type() {

Review comment:
       Note: not all implementations might write LogicalType, even though ConvertedType is deprecated. I had to think a bit about this, but it's fine because it's on the write-side, where we will always write LogicalType going forward.
   
   If this was on the read side, we'd have to also check `ConvertedType` as a fallback.




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