diff --git a/neutron/tests/functional/base.py b/neutron/tests/functional/base.py
index 4e436fc5ab5..f81558b6503 100644
--- a/neutron/tests/functional/base.py
+++ b/neutron/tests/functional/base.py
@@ -314,6 +314,9 @@ class TestOVNFunctionalBase(test_plugin.Ml2PluginV2TestCase,
             trigger_cls.trigger.__self__.__class__ = neutron.wsgi.WorkerService
 
         self.addCleanup(self.stop)
+        # NOTE(ralonsoh): do not access to the DB at exit when the SQL
+        # connection is already closed, to avoid useless exception messages.
+        mock.patch.object(self.mech_driver, '_clean_hash_ring').start()
         self.mech_driver.pre_fork_initialize(
             mock.ANY, mock.ANY, trigger_cls.trigger)