Bug when add measure 'cpu' (gnocchi_resources.yaml

2016-12-05 15:53:48.526 30399 DEBUG gnocchi.storage._carbonara [-] Metric 0d77ab5f-2a78-46a5-ad53-e27e4d77e95b locked during 0.16 seconds process_new_measures /usr/local/lib/python2.7/dist-packages/gnocchi/storage/_carbonara.py:585
2016-12-05 15:53:48.528 30399 ERROR gnocchi.storage._carbonara [-] Error processing new measures
2016-12-05 15:53:48.528 30399 ERROR gnocchi.storage._carbonara Traceback (most recent call last):
2016-12-05 15:53:48.528 30399 ERROR gnocchi.storage._carbonara   File "/usr/local/lib/python2.7/dist-packages/gnocchi/storage/_carbonara.py", line 557, in process_new_measures
2016-12-05 15:53:48.528 30399 ERROR gnocchi.storage._carbonara     ignore_too_old_timestamps=True)
2016-12-05 15:53:48.528 30399 ERROR gnocchi.storage._carbonara   File "/usr/local/lib/python2.7/dist-packages/gnocchi/carbonara.py", line 217, in set_values
2016-12-05 15:53:48.528 30399 ERROR gnocchi.storage._carbonara     before_truncate_callback(self)
2016-12-05 15:53:48.528 30399 ERROR gnocchi.storage._carbonara   File "/usr/local/lib/python2.7/dist-packages/gnocchi/storage/_carbonara.py", line 551, in _map_add_measures
2016-12-05 15:53:48.528 30399 ERROR gnocchi.storage._carbonara     for aggregation in agg_methods))
2016-12-05 15:53:48.528 30399 ERROR gnocchi.storage._carbonara   File "/usr/local/lib/python2.7/dist-packages/gnocchi/storage/_carbonara.py", line 675, in _map_no_thread
2016-12-05 15:53:48.528 30399 ERROR gnocchi.storage._carbonara     return list(itertools.starmap(method, list_of_args))
2016-12-05 15:53:48.528 30399 ERROR gnocchi.storage._carbonara   File "/usr/local/lib/python2.7/dist-packages/gnocchi/storage/_carbonara.py", line 316, in _add_measures
2016-12-05 15:53:48.528 30399 ERROR gnocchi.storage._carbonara     oldest_mutable_timestamp)
2016-12-05 15:53:48.528 30399 ERROR gnocchi.storage._carbonara   File "/usr/local/lib/python2.7/dist-packages/gnocchi/storage/_carbonara.py", line 249, in _store_timeserie_split
2016-12-05 15:53:48.528 30399 ERROR gnocchi.storage._carbonara     offset, data = split.serialize(key, compressed=write_full)
2016-12-05 15:53:48.528 30399 ERROR gnocchi.storage._carbonara AttributeError: 'NoneType' object has no attribute 'serialize'
2016-12-05 15:53:48.528 30399 ERROR gnocchi.storage._carbonara