> They even suggest asyncio could be a replacement for celery... It really is the Wild West out here.
Yes that is complete madness. The last thing I would ever want to do is send an email or use an external API (those are the examples in TFA) in an async thread as part of a request-response cycle. How does error handling or retries work for that background stuff? I don't know the exact ins-and-outs of Djangos new async stuff yet but my guess is that if that mail/API server doesn't respond to your IO then your response to your own HTTP request hangs?
Above all the central and undemonstrated claim is that there are any performance or management advantages to async. I tested sync vs async on this a couple of months ago. The best performance and robustness is with garden variety sync python with a good WSGI server:
Async results in better utilization of system resources... since there aren't entire threads with app state blocked on IO requests (which would consume a chunk of system memory.)
Considering that a web app is most commonly waiting for a database operation, a single server can serve many more active requests simultaneously (since each active request is not allocating an app instance.)
The techempower benchmark predates me and original drafts of my blogpost mention it but I suppose that got cut for various reasons.
The trouble with that benchmark is that (and they're fairly open about this) they aren't keeping things the same between frameworks - there are multiple variables. If you look at the Flask code all the queries are being put through SQLAlchemy but for various async frameworks they're using the database driver directly and using native code libraries for JSON decoding.
I think techempower's benchmarks are interesting but they don't help you do a comparision of async vs sync.
Additionally on the particular benchmark you've linked to #1 is a dead experimental framework that is not in wide use and #2 is Falcon, a sync framework that is in wide use.
Yes that is complete madness. The last thing I would ever want to do is send an email or use an external API (those are the examples in TFA) in an async thread as part of a request-response cycle. How does error handling or retries work for that background stuff? I don't know the exact ins-and-outs of Djangos new async stuff yet but my guess is that if that mail/API server doesn't respond to your IO then your response to your own HTTP request hangs?
Above all the central and undemonstrated claim is that there are any performance or management advantages to async. I tested sync vs async on this a couple of months ago. The best performance and robustness is with garden variety sync python with a good WSGI server:
http://calpaterson.com/async-python-is-not-faster.html
If anyone has any contradictory benchmarks please let me know. I haven't been made aware of any yet.