"Last week, we launched a replacement for our Ruby-on-Rails front-end: a Java server we call Blender. We are pleased to announce that this change has produced a 3x drop in search latencies and will enable us to rapidly iterate on search features in the coming months."
At the same time they did that, they replaced MySQL with a real-time version of Lucene.
Almost every one of these "we switched from A to B and got a 3x speed increase" articles conflates a lot of different variables. The first version you build when you have no traffic and product/market fit is the most important thing. Performance is a low priority. Eventually it hits a bottleneck and you begin to look at performance. Perhaps there is another language out there that is faster than the one you're using. At this point nobody says "let's do an exact code translation from A to B". As you rewrite, you keep a constant eye on performance. It often involves ripping out abstractions and moving closer to the metal. The system you end up with usually looks nothing like the one you started out with, nor should it since it is the product of all of your experience scaling up to that point.
"Last week, we launched a replacement for our Ruby-on-Rails front-end: a Java server we call Blender. We are pleased to announce that this change has produced a 3x drop in search latencies and will enable us to rapidly iterate on search features in the coming months."
http://engineering.twitter.com/2011/04/twitter-search-is-now...