Dataset parquet chunking fix (#349)

* adds return if entities in chunk = 0

* print statement for testing

* adds logging info message

Author: CarlosCoelhoSL

digital_land/package/dataset_parquet.py

@@ -218,6 +218,13 @@ def load_entities_range(
 
         # distinct_fields - list of fields in the field in fact
         rows = self.conn.execute(query).fetchall()
+        # if there are no entities in the entity range then we don't need to proceed
+        if len(rows) == 0:
+            logger.info(
+                f"skipping entity numbers {entity_range[0]} to {entity_range[1]} as there are no entities"
+            )
+            return
+
         distinct_fields = [row[0] for row in rows]
 
         # json fields - list of fields which are present in the fact table which