diff --git a/cinder/db/sqlalchemy/api.py b/cinder/db/sqlalchemy/api.py
index 967ccbfcad9..b1566ec565f 100644
--- a/cinder/db/sqlalchemy/api.py
+++ b/cinder/db/sqlalchemy/api.py
@@ -4567,11 +4567,35 @@ def is_orm_value(obj):
                             sqlalchemy.sql.expression.ColumnElement))
 
 
+def _check_is_not_multitable(values, model):
+    """Check that we don't try to do multitable updates.
+
+    Since PostgreSQL doesn't support multitable updates we want to always fail
+    if we have such a query in our code, even if with MySQL it would work.
+    """
+    used_models = set()
+    for field in values:
+        if isinstance(field, sqlalchemy.orm.attributes.InstrumentedAttribute):
+            used_models.add(field.class_)
+        elif isinstance(field, six.string_types):
+            used_models.add(model)
+        else:
+            raise exception.ProgrammingError(
+                reason='DB Conditional update - Unknown field type, must be '
+                       'string or ORM field.')
+        if len(used_models) > 1:
+            raise exception.ProgrammingError(
+                reason='DB Conditional update - Error in query, multitable '
+                       'updates are not supported.')
+
+
 @require_context
 @_retry_on_deadlock
 def conditional_update(context, model, values, expected_values, filters=(),
                        include_deleted='no', project_only=False, order=None):
     """Compare-and-swap conditional update SQLAlchemy implementation."""
+    _check_is_not_multitable(values, model)
+
     # Provided filters will become part of the where clause
     where_conds = list(filters)
 
diff --git a/cinder/exception.py b/cinder/exception.py
index 50bb43ccc6f..ecc256ead8c 100644
--- a/cinder/exception.py
+++ b/cinder/exception.py
@@ -149,6 +149,10 @@ class GlanceConnectionFailed(CinderException):
     message = _("Connection to glance failed: %(reason)s")
 
 
+class ProgrammingError(CinderException):
+    message = _('Programming error in Cinder: %(reason)s')
+
+
 class NotAuthorized(CinderException):
     message = _("Not authorized.")
     code = 403
diff --git a/cinder/tests/unit/objects/test_base.py b/cinder/tests/unit/objects/test_base.py
index acd9c24bea3..0eb805f6ac7 100644
--- a/cinder/tests/unit/objects/test_base.py
+++ b/cinder/tests/unit/objects/test_base.py
@@ -24,6 +24,7 @@ from sqlalchemy import sql
 from cinder import context
 from cinder import db
 from cinder.db.sqlalchemy import models
+from cinder import exception
 from cinder import objects
 from cinder import test
 from cinder.tests.unit import fake_constants as fake
@@ -664,6 +665,30 @@ class TestCinderObjectConditionalUpdate(test.TestCase):
         self.assertTrue(isinstance(arg, dict))
         self.assertEqual(set(values.keys()), set(arg.keys()))
 
+    def test_conditional_update_multitable_fail(self):
+        volume = self._create_volume()
+        self.assertRaises(exception.ProgrammingError,
+                          volume.conditional_update,
+                          {'status': 'deleting',
+                           objects.Snapshot.model.status: 'available'},
+                          {'status': 'available'})
+
+    def test_conditional_update_multitable_fail_fields_different_models(self):
+        volume = self._create_volume()
+        self.assertRaises(exception.ProgrammingError,
+                          volume.conditional_update,
+                          {objects.Backup.model.status: 'available',
+                           objects.Snapshot.model.status: 'available'})
+
+    def test_conditional_update_not_multitable(self):
+        volume = self._create_volume()
+        with mock.patch('cinder.db.sqlalchemy.api._create_facade_lazily') as m:
+            res = volume.conditional_update(
+                {objects.Volume.model.status: 'deleting',
+                 objects.Volume.model.size: 12}, reflect_changes=False)
+            self.assertTrue(res)
+            self.assertTrue(m.called)
+
 
 class TestCinderDictObject(test_objects.BaseObjectsTestCase):
     @objects.base.CinderObjectRegistry.register_if(False)