Rollback bug on Postgres for multidb applications

[Silvio J. Gutierrez]

Hi there,

Was putting together a fairly straightforward multidb project:

1. Most models go in db1
2. Some models in a special app go to db2.
3. Models from db2 don't ever communicate with db1.

Noticed that, in tests, rollbacks do not work for models in db2. I thought it could be environmental, but I setup a very simple project to reproduce, see ​https://github.com/silviogutierrez/django-multidb-bug

You just need to install the requirements, activate the virtual env and run python manage.py test --keepdb *twice*. You'll notice the model created in the test are not cleared.

Note that it is the --keepdb flag that triggers the bug, as uniqueness constraints will fail for unique fields.

For the purposes of this demo, and just to reproduce this bug, I routed all requests to db2.

Hope this helps someone. Oddly enough, I do see a rollback statement in my DB logs, but it doesn't "take."

Thanks for an awesome project,

Silvio

[Tim Graham]

Does adding ​multi_db = True to your TestCase help?

[Silvio J. Gutierrez]

It does! That seems to fix it.

So is this a documentation gap then? Or should the rollback behavior automatically apply based on the router?

Ideally the latter, I think, but even the former would help others avoid this.

[Tim Graham]

Where do you think the documentation gap is? Is something missing in the section I linked?

[Tim Graham]

Please open a new ticket if you believe any documentation is missing. Thanks!