Best Practices

> The problem with serializing big objects is that serialization brings all sorts of huge problems down into DJs. For example serializing Procs is not possible.

Procs don't have ids and are not persisted in the DB. If it can be stored in a DB it can surely be serialised by DJ. Also, the rule is about AR models, not procs.

> Also it will cement the background queues to use the main db only.
It won't cement anything, but it will make it harder to switch, I agree.

> What do you mean it will make your code uglier and testing harder? 
I mean unit tests. You will be forced to persist all AR models in order to have an id in tests. That means all kinds of problems with validations and bloated test setup.