Determine if we can use PageIndex for predicate

Author: judahrand

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

@@ -301,10 +301,19 @@ fn size_of_columns(
 /// columns are sorted. Sorted columns may be queried more efficiently in the presence of
 /// a PageIndex.
 fn columns_sorted(
-    _columns: &BTreeSet<usize>,
-    _metadata: &ParquetMetaData,
+    columns: &BTreeSet<usize>,
+    metadata: &ParquetMetaData,
 ) -> Result<bool> {
-    // TODO How do we know this?
+    // For now we only set sorted with single col with pageIndex
+    if columns.len() == 1 && metadata.column_index().is_some() {
+        for row_group_num in 0..metadata.num_row_groups() {
+            if !metadata.column_index().unwrap()[row_group_num][*columns.get(&0).unwrap()].is_sorted() {
+                // If any Row Group is not sorted we can't assume we can use the PageIndex.
+                return Ok(false);
+            }
+        }
+        return Ok(true);
+    }
     Ok(false)
 }