Anecdotally, I've seen quite a few Django apps using gevent "just because". If you don't need it, you're just incurring additional overhead for no gain (which is what the author is saying).

There are legitimate usage cases for async patterns, but I have seen them used even in situations where they made things slower.

My post is aimed first and foremost at the Openstack community. Openstack is a large series of CRUD-based applications that don't run any stored procedures or business logic on the database. As to whether or not the "majority" of business apps are stored procedure oriented is very questionable, I've worked for years in finance and while I worked on stored procedure applications for sure, most apps were definitely just CRUD-based apps. The vast majority of apps we see for example in Django or Pyramid are most definitely CRUD based apps.

Also, I use Pypy a lot, and at best I get about a 40-50% speedup. If we factor that into the profiling where I'm showing IO taking up about 5% of the time, that still produces an application that is very much CPU bound.

If there's any point to take from the post, its the historical underpinnings of non-blocking IO, that we use it to poll a bunch of sleeping connections, where we have hundreds or thousands of them. It was never intended to be used on a small set of database connections and I think even if the database calls are slow, it will be very seldom that you'd see asynchronous context switching handling concurrency better than native threads.

Download my suite and run them! Show me asyncio beating out threads in some database-centric scenario. I was really hoping to see that happen in some scenario or another.