Fix performance warning

Author: z3rone

pandas/core/reshape/merge.py

@@ -1641,8 +1641,8 @@ def _validate_validate_kwd(self, validate: str) -> None:
 
         # Check totality of each
         intersect_index = left_merge_index.intersection(right_merge_index)
-        right_total = right_merge_index.drop(intersect_index).empty
-        left_total = left_merge_index.drop(intersect_index).empty
+        right_total = right_merge_index.sort_values().drop(intersect_index).empty
+        left_total = left_merge_index.sort_values().drop(intersect_index).empty
 
         # Check data integrity
         for validation in validations: