Insert or update on table "django_admin_log" violates foreign key constraint when saving new model in admin

Question

When saving a new instance of a model in the admin, I get the following IntegrityError in a traceback:

Traceback:

File "/venv/lib/python2.7/site-packages/django/core/handlers/base.py" in get_response
  149.                     response = self.process_exception_by_middleware(e, request)

File "/users/dan/project/venv/lib/python2.7/site-packages/django/core/handlers/base.py" in get_response
  147.                     response = wrapped_callback(request, *callback_args, **callback_kwargs)

File "/users/dan/project/venv/lib/python2.7/site-packages/django/contrib/admin/options.py" in wrapper
  541.                 return self.admin_site.admin_view(view)(*args, **kwargs)

File "/users/dan/project/venv/lib/python2.7/site-packages/django/utils/decorators.py" in _wrapped_view
  149.                     response = view_func(request, *args, **kwargs)

File "/users/dan/project/venv/lib/python2.7/site-packages/django/views/decorators/cache.py" in _wrapped_view_func
  57.         response = view_func(request, *args, **kwargs)

File "/users/dan/project/venv/lib/python2.7/site-packages/django/contrib/admin/sites.py" in inner
  244.             return view(request, *args, **kwargs)

File "/users/dan/project/venv/lib/python2.7/site-packages/django/contrib/admin/options.py" in add_view
  1435.         return self.changeform_view(request, None, form_url, extra_context)

File "/users/dan/project/venv/lib/python2.7/site-packages/django/utils/decorators.py" in _wrapper
  67.             return bound_func(*args, **kwargs)

File "/users/dan/project/venv/lib/python2.7/site-packages/django/utils/decorators.py" in _wrapped_view
  149.                     response = view_func(request, *args, **kwargs)

File "/users/dan/project/venv/lib/python2.7/site-packages/django/utils/decorators.py" in bound_func
  63.                 return func.__get__(self, type(self))(*args2, **kwargs2)

File "/users/dan/project/venv/lib/python2.7/site-packages/django/utils/decorators.py" in inner
  184.                     return func(*args, **kwargs)

File "/users/dan/project/venv/lib/python2.7/site-packages/django/db/transaction.py" in __exit__
  223.                         connection.commit()

File "/users/dan/project/venv/lib/python2.7/site-packages/django/db/backends/base/base.py" in commit
  242.         self._commit()

File "/users/dan/project/venv/lib/python2.7/site-packages/django/db/backends/base/base.py" in _commit
  211.                 return self.connection.commit()

File "/users/dan/project/venv/lib/python2.7/site-packages/django/db/utils.py" in __exit__
  95.                 six.reraise(dj_exc_type, dj_exc_value, traceback)

File "/users/dan/project/venv/lib/python2.7/site-packages/django/db/backends/base/base.py" in _commit
  211.                 return self.connection.commit()

Exception Type: IntegrityError at /admin/app/invitation/add/
Exception Value: insert or update on table "django_admin_log" violates foreign key constraint "django_admin_log_user_id_52fdd58701c5f563_fk_auth_user_id"
DETAIL:  Key (user_id)=(3) is not present in table "auth_user".

The exact same code works perfectly on another machine.

Answer 1

It looks like my Django user table somehow got stale and contained an outdated primary key. Unfortunately, running ./manage.py migrate didn't seem to fix anything, but with a little help from an old Django trac ticket, I was able to figure out how to easily fix this (warning, you will lose your admin logs).

./manage.py migrate admin 0001
echo "DROP TABLE django_admin_log;" | ./manage.py dbshell
./manage.py sqlmigrate admin 0001 | python manage.py dbshell
./manage.py migrate admin

I'm sure I could run an update in PostgreSQL to the same effect, but I didn't have any data I was worried about keeping.