[notification] Lost connection to MySQL server during query

2016-11-11 08:07:38,801 ERROR monasca_notification.common.repositories.mysql.mysql_repo Couldn't fetch the notification method (2013, 'Lost connection to MySQL server during query')
Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/monasca_notification/common/repositories/mysql/mysql_repo.py", line 131, in get_notification
    cur.execute(self._get_notification_sql, notification_id)
  File "/usr/lib/python2.7/dist-packages/pymysql/cursors.py", line 166, in execute
    result = self._query(query)
  File "/usr/lib/python2.7/dist-packages/pymysql/cursors.py", line 322, in _query
    conn.query(q)
  File "/usr/lib/python2.7/dist-packages/pymysql/connections.py", line 835, in query
    self._affected_rows = self._read_query_result(unbuffered=unbuffered)
  File "/usr/lib/python2.7/dist-packages/pymysql/connections.py", line 1019, in _read_query_result
    result.read()
  File "/usr/lib/python2.7/dist-packages/pymysql/connections.py", line 1302, in read
    first_packet = self.connection._read_packet()
  File "/usr/lib/python2.7/dist-packages/pymysql/connections.py", line 961, in _read_packet
    packet_header = self._read_bytes(4)
  File "/usr/lib/python2.7/dist-packages/pymysql/connections.py", line 998, in _read_bytes
    2013, "Lost connection to MySQL server during query")
OperationalError: (2013, 'Lost connection to MySQL server during query')