A counterexample is Celery when used for things such as network IO. You can't scale horizontally because each process creates a database connection, and you'd n

A counterexample is Celery when used for things such as network IO. You can't scale horizontally because each process creates a database connection, and you'd need a giant database server just to handle a bunch of network IO. The Celery code would probably have to get its parameters from a cache or somewhere that's not the database, but this breaks their suggested use case of accessing the database models when the task actually executes.