+++ This bug was initially created as a clone of Bug #1556720 +++

Description of problem:
Rasca has been observing the following from time to time on his OSP12 setups:

2018-03-14 12:39:39,683 [1] ERROR oslo_db.sqlalchemy.exc_filters: DBAPIError exception wrapped from (pymysql.err.InternalError) (1050, u"Table 'archive_policy' already exists") [SQL: u'\nCREATE TABLE archive_policy (\n\tname VARCHAR(255) NOT NULL, \n\tback_window INTEGER NOT NULL, \n\tdefinition TEXT NOT NULL, \n\taggregation_methods TEXT NOT NULL, \n\tPRIMARY KEY (name)\n)ENGINE=InnoDB CHARSET=utf8\n\n'] Traceback (most recent call last): File "/usr/lib64/python2.7/site-packages/sqlalchemy/engine/base.py", line 1182, in _execute_context context) File "/usr/lib64/python2.7/site-packages/sqlalchemy/engine/default.py", line 470, in do_execute cursor.execute(statement, parameters) File "/usr/lib/python2.7/site-packages/pymysql/cursors.py", line 166, in execute result = self._query(query) File "/usr/lib/python2.7/site-packages/pymysql/cursors.py", line 322, in _query conn.query(q) File "/usr/lib/python2.7/site-packages/pymysql/connections.py", line 856, in query self._affected_rows = self._read_query_result(unbuffered=unbuffered) File "/usr/lib/python2.7/site-packages/pymysql/connections.py", line 1057, in _read_query_result result.read() File "/usr/lib/python2.7/site-packages/pymysql/connections.py", line 1340, in read first_packet = self.connection._read_packet() File "/usr/lib/python2.7/site-packages/pymysql/connections.py", line 1014, in _read_packet packet.check_error() File "/usr/lib/python2.7/site-packages/pymysql/connections.py", line 393, in check_error err.raise_mysql_exception(self._data) File "/usr/lib/python2.7/site-packages/pymysql/err.py", line 107, in raise_mysql_exception raise errorclass(errno, errval) InternalError: (1050, u"Table 'archive_policy' already exists") 


This seems a race around gnocchi-upgrade