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Comment by cgcardona | Hacker News Reader

That's a bit of an oversimplification. Here is a more in depth explanation in the form of a video of a talk called 'Twitter: From Ruby on Rails to the JVM'[1] from O'Reilly Con by Twitter engineer Raffi Krikorian who leads the Applications Services group.

[1] http://www.youtube.com/watch?v=ohHdZXnsNi8

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Didn't watch this video. But as far as I recalled back then, the guys at Twitter was complaining about the slowness of Rails and MRI, as Rails was not asynchronous and MRI was CPU-bound, so instead of fixing this root cause to apply the tricks from V8 to Javascript to improve Ruby，they chose the more "pragmatic" way to use Netty that is asynchronous and Scala that is way faster.

I don't accuse them of not saving the world, but Ruby and Rails lost a great opportunity to dominate the web community. If Rails were as performant as Node.js, I doubt lots of companies would change gears.

I think organization type plays a role here too. ROR is an excellent fit for startups where speed of iteration is paramount; but once an organization settles on a business model and functionality matures a bit, the code stops changing so rapidly and the ability to do rapid development is not important any longer. At the same time performance becomes increasingly critical due to costs of scale. Hence a switch to something like scala makes perfect sense.

> I don't accuse them of not saving the world, but Ruby and Rails lost a great opportunity to dominate the web community.

They didn't lose this opportunity because of Twitter, they lost it because the fact that Ruby is dynamically typed puts a hard limit on how fast it can be. Twitter tried very hard to make it scale before making the decision to switch to Java, and they just couldn't do it.

The task was just impossible, switching to Java was the only reasonable decision given their constraints.

Javascript is also a dynamically typed script language, which Google managed to make at least one order of magnitude faster with V8. It's likely same tricks can be applied to Ruby.

Google has a full-time team of some of the best compiler writers in the world wholly dedicated to tuning Javascript, and they have spent literally years to get it to perform how it does today, and it's still far from competing with the JVM, and will likely never be able to do basic things such as multithreading and proper type safety. Twitter was absolutely right in doing what they did.

https://www.paypal-engineering.com/2013/11/22/node-js-at-pay...

Seems that node.js outperforms the JVM for WebDev nowadays.

Otoh they don't use some top secret innovations but decades old techniques accessible to everyone.

And language benchmarks don't tell the whole story. In Java, idiomatic and typical code will be optimized very well whereas in Javascript such code runs easily at least an order of magnitude slower than its potential. Try to run some idiomatic JS through https://github.com/petkaantonov/nodeperf/ and see it explode :)

So even if Javascript can be shown in some benchmark to close on the JVM, the benchmarks are ignoring the fact that you cannot write Javascript carelessly to get anywhere near those speeds unlike with Java.

There are lots of dynamic languages with native compilers around, offering speeds that beat Ruby's canonical implementation.

Are you aware that Hotspot, Sun/Oracle's JIT compiler was actually developed for a Smalltalk dialect, Self?

LuaJIT shows dynamically typed languages can be fast. And even plain Lua is enormously faster than Ruby. Complexity costs, not necessarily being dynamic.

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