id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
26541	Add a DatabaseFeatures.supports_transactions() method for MySQL	Marcin Nowak	Mariusz Felisiak	"When something goes wrong during checking database features, the state of db stays affected: 

{{{
  File ""/home/marcin/myproject/eggs/Django-1.8.6-py2.7.egg/django/test/testcases.py"", line 182, in __call__
    self._pre_setup()
  File ""/home/marcin/myproject/eggs/Django-1.8.6-py2.7.egg/django/test/testcases.py"", line 787, in _pre_setup
    self._fixture_setup()
  File ""/home/marcin/myproject/eggs/Django-1.8.6-py2.7.egg/django/test/testcases.py"", line 986, in _fixture_setup
    if not connections_support_transactions():
  File ""/home/marcin/myproject/eggs/Django-1.8.6-py2.7.egg/django/test/testcases.py"", line 911, in connections_support_transactions
    for conn in connections.all())
  File ""/home/marcin/myproject/eggs/Django-1.8.6-py2.7.egg/django/test/testcases.py"", line 911, in <genexpr>
    for conn in connections.all())
  File ""/home/marcin/myproject/eggs/Django-1.8.6-py2.7.egg/django/utils/functional.py"", line 59, in __get__
    res = instance.__dict__[self.name] = self.func(instance)
  File ""/home/marcin/myproject/eggs/Django-1.8.6-py2.7.egg/django/db/backends/base/features.py"", line 217, in supports_transactions
    cursor.execute('CREATE TABLE ROLLBACK_TEST (X INT)')
  File ""/home/marcin/myproject/eggs/Django-1.8.6-py2.7.egg/django/db/backends/utils.py"", line 64, in execute
    return self.cursor.execute(sql, params)
  File ""/home/marcin/myproject/eggs/Django-1.8.6-py2.7.egg/django/db/utils.py"", line 97, in __exit__
    six.reraise(dj_exc_type, dj_exc_value, traceback)
  File ""/home/marcin/myproject/eggs/Django-1.8.6-py2.7.egg/django/db/backends/utils.py"", line 62, in execute
    return self.cursor.execute(sql)
  File ""/home/marcin/myproject/eggs/Django-1.8.6-py2.7.egg/django/db/backends/mysql/base.py"", line 124, in execute
    return self.cursor.execute(query, args)
  File ""/home/marcin/myproject/eggs/MySQL_python-1.2.3-py2.7-linux-x86_64.egg/MySQLdb/cursors.py"", line 174, in execute
    self.errorhandler(self, exc, value)
  File ""/home/marcin/myproject/eggs/MySQL_python-1.2.3-py2.7-linux-x86_64.egg/MySQLdb/connections.py"", line 36, in defaulterrorhandler
    raise errorclass, errorvalue
OperationalError: (1050, ""Table 'ROLLBACK_TEST' already exists"")
}}}

1. Django should not create any table during startup - there may be readonly or sensitive databases connected
2. Let the Django do some cleanups, if it must ""dig"" databases.
"	Cleanup/optimization	closed	Database layer (models, ORM)	1.8	Normal	fixed			Ready for checkin	0	0	0	0	0	0