Fantastic. Instead of facing up to the crippling inadequacies of Ruby's single threaded implementation, we get a mad scientist solution.
I swear Ruby attracts bad thinking like a magnet.
I swear Ruby attracts bad thinking like a magnet.
There's nothing wrong with an app stack that is async up through the database client. Async is good. There are things that are wrong with app stacks that are entirely threaded, but we can have that argument somewhere else. But there is something wrong with the idea that we can have the best of both worlds, if we just try to make async code look like threaded code.
As someone has already pointed out, it's not about the threading, it's about turning a blocking request, into an asynchronous one. (Deferring work until you have the data to perform meaningful actions with it).
It would be much simpler to either make the database driver itself non-blocking (Postgres' client library supports async queries, for instance), or use a dedicated pool of threads to perform blocking DB operations. It might be that Ruby's threading is too broken for the latter to be feasible, but it still makes using DBSlayer just to get async DB operations needless overkill.