I wonder how many people bitching here are actual customers who are having problems that haven't been address with a solution. I'm guessing that number is low.
Oh, you're a potential customer? That's why you're bitching? About a problem you may or may not have if you actually choose the product? Think about that argument for a second.
I've never seen such a transparent response and follow up as I have from Heroku on this issue. Most other companies would have gone into immediate damage mitigation mode and let the wound heal instead of re-opening it and giving feedback on how to fix the problem as Heroku has.
I applaud the Heroku team for their effort on their platform and being a kickass company.
I'm a real customer with real problems. Grep this page for latchkey's description of it.
The funny thing is, I don't have much sympathy for Rails users. Scaling problems with a single-threaded, serial request-processing architecture? No surprise there. But we have inexplicable H12 problems with Node.js. There's something broken in the system and it isn't random routing.
There's nothing wrong with Node's concurrency. Our app, like most webapps, is I/O bound. Any individual instance should be able to handle thousands of concurrent requests as long as they are all blocked on I/O.
Being able to process more than one concurrent request (as Node can) is "real concurrency". Java-style native threading is a step above and beyond this, and unnecessary for most web applications.