def _save(self):
        primitive = self.obj_to_primitive()
        payload = jsonutils.dumps(primitive)

        values = {"migration_context": payload}
        db.instance_extra_update_by_uuid(self._context, self.instance_uuid, values)
        self.obj_reset_changes()

 def create(self, context):
     topology = self.topology_from_obj()
     if not topology:
         return
     values = {'numa_topology': topology.to_json()}
     db.instance_extra_update_by_uuid(context, self.instance_uuid,
                                      values)
     self.obj_reset_changes()

 def save(self, context):
     blob = [{'count': x.count,
              'spec': x.spec,
              'alias_name': x.alias_name,
              'is_new': x.is_new,
              'request_id': x.request_id} for x in self.requests]
     requests = jsonutils.dumps(blob)
     db.instance_extra_update_by_uuid(context, self.instance_uuid,
                                      {'pci_requests': requests})

 def _save_vcpu_model(self, context):
     # TODO(yjiang5): should merge the db accesses for all the extra
     # fields
     if "vcpu_model" in self.obj_what_changed():
         if self.vcpu_model:
             update = jsonutils.dumps(self.vcpu_model.obj_to_primitive())
         else:
             update = None
         db.instance_extra_update_by_uuid(context, self.uuid, {"vcpu_model": update})

 def _save_flavor(self, context):
     # FIXME(danms): We can do this smarterly by updating this
     # with all the other extra things at the same time
     flavor_info = {
         "cur": self.flavor.obj_to_primitive(),
         "old": (self.old_flavor and self.old_flavor.obj_to_primitive() or None),
         "new": (self.new_flavor and self.new_flavor.obj_to_primitive() or None),
     }
     db.instance_extra_update_by_uuid(context, self.uuid, {"flavor": jsonutils.dumps(flavor_info)})
     self.obj_reset_changes(["flavor", "old_flavor", "new_flavor"])

 def _save_flavor(self, context):
     if not any([x in self.obj_what_changed() for x in
                 ('flavor', 'old_flavor', 'new_flavor')]):
         return
     # FIXME(danms): We can do this smarterly by updating this
     # with all the other extra things at the same time
     flavor_info = {
         'cur': self.flavor.obj_to_primitive(),
         'old': (self.old_flavor and
                 self.old_flavor.obj_to_primitive() or None),
         'new': (self.new_flavor and
                 self.new_flavor.obj_to_primitive() or None),
     }
     db.instance_extra_update_by_uuid(
         context, self.uuid,
         {'flavor': jsonutils.dumps(flavor_info)})
     self.obj_reset_changes(['flavor', 'old_flavor', 'new_flavor'])

 def delete_by_instance_uuid(cls, context, instance_uuid):
     values = {'numa_topology': None}
     db.instance_extra_update_by_uuid(context, instance_uuid,
                                      values)

 def _save(self):
     values = {'numa_topology': self._to_json()}
     db.instance_extra_update_by_uuid(self._context, self.instance_uuid,
                                      values)
     self.obj_reset_changes()

 def save(self, context):
     blob = self.to_json()
     db.instance_extra_update_by_uuid(context, self.instance_uuid,
                                      {'pci_requests': blob})

 def _destroy(cls, context, instance_uuid):
     values = {'migration_context': None}
     db.instance_extra_update_by_uuid(context, instance_uuid, values)