diff --git a/addons/auth_openid/res_users.py b/addons/auth_openid/res_users.py
index 1c6c635118a..bbfb064fb0f 100644
--- a/addons/auth_openid/res_users.py
+++ b/addons/auth_openid/res_users.py
@@ -63,24 +63,17 @@ class res_users(osv.osv):
                 cr.commit()
                 return res[0] if res else False
 
-    def check(self, db, uid, passwd):
+    def check_credentials(self, cr, uid, password):
         try:
-            return super(res_users, self).check(db, uid, passwd)
+            return super(res_users, self).check_credentials(cr, uid, password)
         except openerp.exceptions.AccessDenied:
-            if not passwd:
+            cr.execute('''SELECT COUNT(1)
+                            FROM res_users
+                           WHERE id=%s
+                             AND openid_key=%s
+                             AND active=%s''',
+                        (int(uid), passwd, True))
+            if not cr.fetchone()[0]:
                 raise
-            with RegistryManager.get(db).cursor() as cr:
-                cr.execute('''SELECT COUNT(1)
-                                FROM res_users
-                               WHERE id=%s
-                                 AND openid_key=%s
-                                 AND active=%s''',
-                            (int(uid), passwd, True))
-                if not cr.fetchone()[0]:
-                    raise
-                self._uid_cache.setdefault(db, {})[uid] = passwd
-
-
-
 
 # vim:expandtab:smartindent:tabstop=4:softtabstop=4:shiftwidth=4:
diff --git a/openerp/addons/base/res/res_users.py b/openerp/addons/base/res/res_users.py
index 4670d93ef68..4aebc66c904 100644
--- a/openerp/addons/base/res/res_users.py
+++ b/openerp/addons/base/res/res_users.py
@@ -142,7 +142,7 @@ class res_users(osv.osv):
         avatar, ... The user model is now dedicated to technical data.
     """
     __admin_ids = {}
-    _uid_cache = {}
+    __uid_cache = {}
     _inherits = {
         'res.partner': 'partner_id',
     }
@@ -341,10 +341,10 @@ class res_users(osv.osv):
         clear = partial(self.pool['ir.rule'].clear_cache, cr)
         map(clear, ids)
         db = cr.dbname
-        if db in self._uid_cache:
+        if db in self.__uid_cache:
             for id in ids:
-                if id in self._uid_cache[db]:
-                    del self._uid_cache[db][id]
+                if id in self.__uid_cache[db]:
+                    del self.__uid_cache[db][id]
         self._context_get.clear_cache(self)
         self.has_group.clear_cache(self)
         return res
@@ -353,10 +353,10 @@ class res_users(osv.osv):
         if 1 in ids:
             raise osv.except_osv(_('Can not remove root user!'), _('You can not remove the admin user as it is used internally for resources created by Odoo (updates, module installation, ...)'))
         db = cr.dbname
-        if db in self._uid_cache:
+        if db in self.__uid_cache:
             for id in ids:
-                if id in self._uid_cache[db]:
-                    del self._uid_cache[db][id]
+                if id in self.__uid_cache[db]:
+                    del self.__uid_cache[db][id]
         return super(res_users, self).unlink(cr, uid, ids, context=context)
 
     def name_search(self, cr, user, name='', args=None, operator='ilike', context=None, limit=100):
@@ -495,15 +495,12 @@ class res_users(osv.osv):
         if not passwd:
             # empty passwords disallowed for obvious security reasons
             raise openerp.exceptions.AccessDenied()
-        if self._uid_cache.get(db, {}).get(uid) == passwd:
+        if self.__uid_cache.setdefault(db, {}).get(uid) == passwd:
             return
         cr = self.pool.cursor()
         try:
             self.check_credentials(cr, uid, passwd)
-            if self._uid_cache.has_key(db):
-                self._uid_cache[db][uid] = passwd
-            else:
-                self._uid_cache[db] = {uid:passwd}
+            self.__uid_cache[db][uid] = passwd
         finally:
             cr.close()