caching_error

[2016-08-03 15:03:07,045] {_internal.py:87} INFO - 127.0.0.1 - - [03/Aug/2016 15:03:07] "POST /admin/dagrun/new/?url=%2Fadmin%2Fdagrun%2F HTTP/1.1" 500 -
Traceback (most recent call last):
  File "/Users/norman/src/incubator-airflow/venv/lib/python2.7/site-packages/Flask-0.10.1-py2.7.egg/flask/app.py", line 1836, in __call__
    return self.wsgi_app(environ, start_response)
  File "/Users/norman/src/incubator-airflow/venv/lib/python2.7/site-packages/Flask-0.10.1-py2.7.egg/flask/app.py", line 1820, in wsgi_app
    response = self.make_response(self.handle_exception(e))
  File "/Users/norman/src/incubator-airflow/venv/lib/python2.7/site-packages/Flask-0.10.1-py2.7.egg/flask/app.py", line 1403, in handle_exception
    reraise(exc_type, exc_value, tb)
  File "/Users/norman/src/incubator-airflow/venv/lib/python2.7/site-packages/Flask-0.10.1-py2.7.egg/flask/app.py", line 1817, in wsgi_app
    response = self.full_dispatch_request()
  File "/Users/norman/src/incubator-airflow/venv/lib/python2.7/site-packages/Flask-0.10.1-py2.7.egg/flask/app.py", line 1477, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/Users/norman/src/incubator-airflow/venv/lib/python2.7/site-packages/Flask-0.10.1-py2.7.egg/flask/app.py", line 1381, in handle_user_exception
    reraise(exc_type, exc_value, tb)
  File "/Users/norman/src/incubator-airflow/venv/lib/python2.7/site-packages/Flask-0.10.1-py2.7.egg/flask/app.py", line 1475, in full_dispatch_request
    rv = self.dispatch_request()
  File "/Users/norman/src/incubator-airflow/venv/lib/python2.7/site-packages/Flask-0.10.1-py2.7.egg/flask/app.py", line 1461, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "/Users/norman/src/incubator-airflow/venv/lib/python2.7/site-packages/Flask_Admin-1.4.1-py2.7.egg/flask_admin/base.py", line 69, in inner
    return self._run_view(f, *args, **kwargs)
  File "/Users/norman/src/incubator-airflow/venv/lib/python2.7/site-packages/Flask_Admin-1.4.1-py2.7.egg/flask_admin/base.py", line 368, in _run_view
    return fn(self, *args, **kwargs)
  File "/Users/norman/src/incubator-airflow/venv/lib/python2.7/site-packages/Flask_Admin-1.4.1-py2.7.egg/flask_admin/model/base.py", line 1920, in create_view
    model = self.create_model(form)
  File "/Users/norman/src/incubator-airflow/venv/lib/python2.7/site-packages/Flask_Admin-1.4.1-py2.7.egg/flask_admin/contrib/sqla/view.py", line 1022, in create_model
    if not self.handle_view_exception(ex):
  File "/Users/norman/src/incubator-airflow/venv/lib/python2.7/site-packages/Flask_Admin-1.4.1-py2.7.egg/flask_admin/contrib/sqla/view.py", line 1005, in handle_view_exception
    return super(ModelView, self).handle_view_exception(exc)
  File "/Users/norman/src/incubator-airflow/venv/lib/python2.7/site-packages/Flask_Admin-1.4.1-py2.7.egg/flask_admin/contrib/sqla/view.py", line 1017, in create_model
    form.populate_obj(model)
  File "/Users/norman/src/incubator-airflow/venv/lib/python2.7/site-packages/WTForms-2.1-py2.7.egg/wtforms/form.py", line 96, in populate_obj
    field.populate_obj(obj, name)
  File "/Users/norman/src/incubator-airflow/venv/lib/python2.7/site-packages/WTForms-2.1-py2.7.egg/wtforms/fields/core.py", line 327, in populate_obj
    setattr(obj, name, self.data)
  File "<string>", line 1, in __set__

  File "/Users/norman/src/incubator-airflow/airflow/models.py", line 3466, in set_state
    DagStat.set_dirty(self.dag_id)
  File "/Users/norman/src/incubator-airflow/airflow/models.py", line 2488, in set_dirty
    session.commit()
  File "build/bdist.macosx-10.11-x86_64/egg/sqlalchemy/orm/session.py", line 811, in commit
    self.transaction.commit()
  File "build/bdist.macosx-10.11-x86_64/egg/sqlalchemy/orm/session.py", line 407, in commit
    if self.session._enable_transaction_accounting:
AttributeError: 'NoneType' object has no attribute '_enable_transaction_accounting'