diff --git a/nova/db/sqlalchemy/api.py b/nova/db/sqlalchemy/api.py
index fc35a5faee12..64c6724e647d 100644
--- a/nova/db/sqlalchemy/api.py
+++ b/nova/db/sqlalchemy/api.py
@@ -6041,7 +6041,7 @@ def migrate_flavor_data(context, max_count, flavor_cache):
     from nova import objects
 
     query = _instance_get_all_query(context, joins=['extra', 'extra.flavor']).\
-                join(models.Instance.extra).\
+                outerjoin(models.Instance.extra).\
                 filter(models.InstanceExtra.flavor.is_(None))
     if max_count is not None:
         instances = query.limit(max_count)
@@ -6069,6 +6069,11 @@ def migrate_flavor_data(context, max_count, flavor_cache):
 
         _augment_flavors_to_migrate(instance, flavor_cache)
         if instance.obj_what_changed():
+            if db_instance.get('extra') is None:
+                _instance_extra_create(context,
+                                       {'instance_uuid': db_instance['uuid']})
+                LOG.debug(
+                    'Created instance_extra for %s' % db_instance['uuid'])
             instance.save(expected_task_state=[None])
             count_hit += 1
 
diff --git a/nova/tests/unit/db/test_db_api.py b/nova/tests/unit/db/test_db_api.py
index 8fc8d540fe46..7cc9c94a52c1 100644
--- a/nova/tests/unit/db/test_db_api.py
+++ b/nova/tests/unit/db/test_db_api.py
@@ -7629,6 +7629,31 @@ class FlavorMigrationTestCase(test.TestCase):
         self.assertEqual(3, match)
         self.assertEqual(0, done)
 
+    def test_migrate_flavor_gets_missing_extra_rows(self):
+        ctxt = context.get_admin_context()
+        flavor = flavors.get_default_flavor()
+        sysmeta = flavors.save_flavor_info({}, flavor)
+        values1 = {'uuid': str(stdlib_uuid.uuid4()),
+                  'system_metadata': sysmeta,
+                  'extra': {'flavor': None},
+        }
+        db.instance_create(ctxt, values1)
+        values2 = {'uuid': str(stdlib_uuid.uuid4()),
+                  'system_metadata': sysmeta,
+        }
+        inst2 = db.instance_create(ctxt, values2)
+        sqlalchemy_api.model_query(ctxt, models.InstanceExtra).\
+            filter_by(instance_uuid=inst2.uuid).delete()
+
+        self.assertIsNone(db.instance_extra_get_by_instance_uuid(
+            ctxt, inst2.uuid))
+        match, done = db.migrate_flavor_data(ctxt, None, {})
+        self.assertEqual(2, match)
+        self.assertEqual(2, done)
+        extra = db.instance_extra_get_by_instance_uuid(ctxt, inst2.uuid)
+        self.assertIsNotNone(extra)
+        self.assertIsNotNone(extra.flavor)
+
 
 class ArchiveTestCase(test.TestCase):