Blah, blah, blah.
Jesus f’ing Christ. We’re talking like we’re experts when everybody seems to have missed the real problem, including the dorks at Twitter.
Here’s the damned problem:
The damned site is synchronous. That’s the problem. Threads are waiting for the database, and those threads are tied up until the database can respond back.
I have no idea if Ruby has an asynchronous programming model. If it does, then it’s Twitter’s own fault for totally missing the boat. If it’s not in Ruby, then Ruby sucks. Either way, somebody blew it.