Why would autocommit in django 1.4 slow down unit tests?
The slowed down unit tests were due to the additional cost of opening and committing a transaction with every object created as part of setUp, and did not reflect a slow down in performance in a live environment.
Django 1.4 operates by default with the database-level autocommit setting off. I have recently tried turning this setting on and it has slowed down my test suite considerably. 
DATABASES['default']['OPTIONS'].update({'autocommit': True})
My understanding is that now every call to create, save etc. by default opens a transaction and issues a commit statement. Would the cost of all these additional transactions be enough to explain the slow-down of the unit tests? How does the django TestCase transaction behaviour come in to play with this (operating each test within a transaction and rolling back once completed)? Should we expect the performance reduction in the unit tests to be reflective of performance of the views in production?