migration 86 fails when database table dns_domains is already InnoDB

Hi, from my investigation it seems that altering a table from innodb causes problems if the table has registered foreign keys. There is further information about the problem on this random blog [1].

I came across the bug while working with a fresh devstack (master branch) install on a precise vm.

1. http://www.xaprb.com/blog/2006/08/22/mysqls-error-1025-explained/

Command failed, please check log for more info
2012-04-30 14:34:40 CRITICAL nova [-] (OperationalError) (1025, "Error on rename of './nova/#sql-67f4_40' to './nova/dns_domains' (errno: 150)") 'ALTER TABLE dns_domains Engine=InnoDB' ()
2012-04-30 14:34:40 TRACE nova Traceback (most recent call last):
2012-04-30 14:34:40 TRACE nova File "/usr/local/bin/nova-manage", line 7, in <module>
2012-04-30 14:34:40 TRACE nova execfile(__file__)
2012-04-30 14:34:40 TRACE nova File "/opt/stack/nova/bin/nova-manage", line 1754, in <module>
2012-04-30 14:34:40 TRACE nova main()
2012-04-30 14:34:40 TRACE nova File "/opt/stack/nova/bin/nova-manage", line 1741, in main
2012-04-30 14:34:40 TRACE nova fn(*fn_args, **fn_kwargs)
2012-04-30 14:34:40 TRACE nova File "/opt/stack/nova/bin/nova-manage", line 1106, in sync
2012-04-30 14:34:40 TRACE nova return migration.db_sync(version)
2012-04-30 14:34:40 TRACE nova File "/opt/stack/nova/nova/db/migration.py", line 30, in db_sync
2012-04-30 14:34:40 TRACE nova return IMPL.db_sync(version=version)
2012-04-30 14:34:40 TRACE nova File "/opt/stack/nova/nova/db/sqlalchemy/migration.py", line 83, in db_sync
2012-04-30 14:34:40 TRACE nova return versioning_api.upgrade(get_engine(), repository, version)
2012-04-30 14:34:40 TRACE nova File "/usr/lib/python2.7/dist-packages/migrate/versioning/api.py", line 186, in upgrade
2012-04-30 14:34:40 TRACE nova return _migrate(url, repository, version, upgrade=True, err=err, **opts)
2012-04-30 14:34:40 TRACE nova File "<string>", line 2, in _migrate
2012-04-30 14:34:40 TRACE nova File "/opt/stack/nova/nova/db/sqlalchemy/migration.py", line 39, in patched_with_engine
2012-04-30 14:34:40 TRACE nova return f(*a, **kw)
2012-04-30 14:34:40 TRACE nova File "/usr/lib/python2.7/dist-packages/migrate/versioning/api.py", line 366, in _migrate
2012-04-30 14:34:40 TRACE nova schema.runchange(ver, change, changeset.step)
2012-04-30 14:34:40 TRACE nova File "/usr/lib/python2.7/dist-packages/migrate/versioning/schema.py", line 91, in runchange
2012-04-30 14:34:40 TRACE nova change.run(self.engine, step)
2012-04-30 14:34:40 TRACE nova File "/usr/lib/python2.7/dist-packages/migrate/versioning/script/py.py", line 145, in run
2012-04-30 14:34:40 TRACE nova script_func(engine)
2012-04-30 14:34:40 TRACE nova File "/opt/stack/nova/nova/db/sqlalchemy/migrate_repo/versions/086_set_engine_mysql_innodb.py", line 33, in upgrade
2012-04-30 14:34:40 TRACE nova migrate_engine.execute("ALTER TABLE dns_domains Engine=InnoDB")
2012-04-30 14:34:40 TRACE nova File "/usr/lib/python2.7/dist-packages/sqlalchemy/engine/base.py", line 2297, in execute
2012-04-30 14:34:40 TRACE nova return connection.execute(statement, *multiparams, **params)
2012-04-30 14:34:40 TRACE nova File "/usr/lib/python2.7/dist-packages/sqlalchemy/engine/base.py", line 1405, in execute
2012-04-30 14:34:40 TRACE nova params)
2012-04-30 14:34:40 TRACE nova File "/usr/lib/python2.7/dist-packages/sqlalchemy/engine/base.py", line 1582, in _execute_text
2012-04-30 14:34:40 TRACE nova statement, parameters
2012-04-30 14:34:40 TRACE nova File "/usr/lib/python2.7/dist-packages/sqlalchemy/engine/base.py", line 1646, in _execute_context
2012-04-30 14:34:40 TRACE nova context)
2012-04-30 14:34:40 TRACE nova File "/usr/lib/python2.7/dist-packages/sqlalchemy/engine/base.py", line 1639, in _execute_context
2012-04-30 14:34:40 TRACE nova context)
2012-04-30 14:34:40 TRACE nova File "/usr/lib/python2.7/dist-packages/sqlalchemy/engine/default.py", line 330, in do_execute
2012-04-30 14:34:40 TRACE nova cursor.execute(statement, parameters)
2012-04-30 14:34:40 TRACE nova File "/usr/lib/python2.7/dist-packages/MySQLdb/cursors.py", line 174, in execute
2012-04-30 14:34:40 TRACE nova self.errorhandler(self, exc, value)
2012-04-30 14:34:40 TRACE nova File "/usr/lib/python2.7/dist-packages/MySQLdb/connections.py", line 36, in defaulterrorhandler
2012-04-30 14:34:40 TRACE nova raise errorclass, errorvalue
2012-04-30 14:34:40 TRACE nova OperationalError: (OperationalError) (1025, "Error on rename of './nova/#sql-67f4_40' to './nova/dns_domains' (errno: 150)") 'ALTER TABLE dns_domains Engine=InnoDB' ()
2012-04-30 14:34:40 TRACE nova