diff --git a/openerp/osv/orm.py b/openerp/osv/orm.py
index 5197f92f3d0..1320ee3c6dc 100644
--- a/openerp/osv/orm.py
+++ b/openerp/osv/orm.py
@@ -2054,8 +2054,8 @@ class orm_memory(orm_template):
 
     _protected = ['read', 'write', 'create', 'default_get', 'perm_read', 'unlink', 'fields_get', 'fields_view_get', 'search', 'name_get', 'distinct_field_get', 'name_search', 'copy', 'import_data', 'search_count', 'exists']
     _inherit_fields = {}
-    _max_count = config.get('osv_memory_count_limit')
-    _max_hours = config.get('osv_memory_age_limit')
+    _max_count = None
+    _max_hours = None
     _check_time = 20
 
     @classmethod
@@ -2067,6 +2067,8 @@ class orm_memory(orm_template):
         self.datas = {}
         self.next_id = 0
         self.check_id = 0
+        self._max_count = config.get('osv_memory_count_limit')
+        self._max_hours = config.get('osv_memory_age_limit')
         cr.execute('delete from wkf_instance where res_type=%s', (self._name,))
 
     def _check_access(self, uid, object_id, mode):