Hi everyone, I have raised few days ago an issue ( https://code.djangoproject.com/ticket/26822) I encountered when using --keepdb and --parallel option. I have proposed a patch (https://github.com/django/django/pull/6884), and after some exchanged with Aymeric Augustin, I have been encouraged to post to this list.
The context is the following: - I run the first time the tests on my Django project (1.9.7) with --keepdb and --parallel option. - All databases are kept, everything is working as expected. - I add a new field in a model, generate a new migration and add some tests related to that field. - I run again my tests with --keepdb and --parallel option: they are now failing because this new field has not been created in cloned databases. After some investigation, I have seen that, in case of keepdb context, in django/db/backends/*/creation.py, if the cloned databases already exist, we don't touch them, which leads to this new field not created in cloned ones. I have proposed in the PR to rebuild the cloned databases, even with keepdb option, to be sure that we always have the cloned databases with the latest migration state. The problem with this method is that it will increase test database initialization time, as we will now systematically copy all cloned databases, even with --keepdb option (except the default one). We could have just documented this limitation, but I don't think that my situation is a really rare edge case in terms of process, so I was suggesting to add a new option to be able to reset the cloned databases if needed (let's name it --parallel-clone-reset). I don't really like the idea of adding a new option, as it impacts the test runner, the clone_test_db function signature, ... but I have not found a better idea to at the same time keep the performances with --keepdb and --parallel, and handle these newly added migrations to a project. To summarize my proposal, this option (--parallel-clone-reset, or any other name) should be used only if you are using --keepdb and --parallel options at the same time, and when you have added a new migration between 2 test run. I'm not sure my explanation was clear enough, but I would really like to have your feedbacks about it. Regards, Romain Garrigues. -- You received this message because you are subscribed to the Google Groups "Django developers (Contributions to Django itself)" group. To unsubscribe from this group and stop receiving emails from it, send an email to django-developers+unsubscr...@googlegroups.com. To post to this group, send email to django-developers@googlegroups.com. Visit this group at https://groups.google.com/group/django-developers. To view this discussion on the web visit https://groups.google.com/d/msgid/django-developers/CAE_LG9y_FXz0Pva2Aa9FHebsqKvE8bbAs-gDgs-jdS6KS0wRkQ%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
