diff --git a/product.py b/product.py
index 4482b5092c..d2d104d563 100644
--- a/product.py
+++ b/product.py
@@ -56,7 +56,9 @@ class Template(metaclass=PoolMeta):
 
     @classmethod
     def __register__(cls, module_name):
-        cursor = Transaction().connection.cursor()
+        transaction = Transaction()
+        cursor = transaction.connection.cursor()
+        update = transaction.connection.cursor()
         table = cls.__table_handler__(module_name)
         sql_table = cls.__table__()
 
@@ -66,11 +68,11 @@ class Template(metaclass=PoolMeta):
         if table.column_exist('delivery_time'):
             cursor.execute(*sql_table.select(
                     sql_table.id, sql_table.delivery_time))
-            for id_, delivery_time in cursor.fetchall():
+            for id_, delivery_time in cursor:
                 if delivery_time is None:
                     continue
                 lead_time = datetime.timedelta(days=delivery_time)
-                cursor.execute(*sql_table.update(
+                update.execute(*sql_table.update(
                         [sql_table.lead_time],
                         [lead_time],
                         where=sql_table.id == id_))
diff --git a/sale.py b/sale.py
index cd84884440..ff467943ad 100644
--- a/sale.py
+++ b/sale.py
@@ -1790,7 +1790,7 @@ class OpenCustomer(Wizard):
         sale = Sale.__table__()
 
         cursor.execute(*sale.select(sale.party, group_by=sale.party))
-        customer_ids = [line[0] for line in cursor.fetchall()]
+        customer_ids = [line[0] for line in cursor]
         action['pyson_domain'] = PYSONEncoder().encode(
             [('id', 'in', customer_ids)])
         wizard = Wizard(ModelData.get_id('sale', 'act_open_customer'))
diff --git a/sale_reporting.py b/sale_reporting.py
index 154757f78e..aa99ad6218 100644
--- a/sale_reporting.py
+++ b/sale_reporting.py
@@ -532,12 +532,12 @@ class CategoryTree(ModelSQL, ModelView):
             sub_ids = list(sub_ids)
             where = reduce_ids(table.id, sub_ids)
             cursor.execute(*table.select(table.id, table.parent, where=where))
-            parents.update(cursor.fetchall())
+            parents.update(cursor)
 
             where = reduce_ids(reporting_category.id, sub_ids)
             cursor.execute(
                 *reporting_category.select(reporting_category.id, where=where))
-            reporting_categories.extend(r for r, in cursor.fetchall())
+            reporting_categories.extend(r for r, in cursor)
 
         result = {}
         reporting_categories = ReportingCategory.browse(reporting_categories)