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Comment by rafark | Hacker News Reader

Facebook had hundreds of millions daily active users before writing a compiler.

98% of the people that initially thought (Python for Threads - OMG performance!) work at a company that will tell you straight up they expect 100M RPS in a year or two, will actually only get to 50k RPS in 5 years before the "Our incredible journey" letter is issued.

I use an unscientific rule of thumb that 10-100x scaling is about the most to plan for except for exceptional cases. Anything beyond that ends up with overcomplicated bloat for a "tomorrow" problem.

Being able to handle spikes and iterate quickly is probably more important.

And lots of nodes not able to keep up, rewriting backend services in C++ to make up for it.

> Facebook had hundreds of millions daily active users before writing a compiler.

In other words, Facebook felt compelled to write a compiler when they had hundreds of millions daily active users.

If you have hundreds of millions of daily active users then needing to write a compiler isn't the end of the world.

Compiling PHP into machine code sounds pretty much impossible, are they using some subset of the language? Does the compiled code use a garbage collector? Or reference counting?

> are they using some subset of the language?

They're using a derived language called Hack.

> Does the compiled code use a garbage collector? Or reference counting?

Not sure but it's open source so I'm sure you can dig up the answers one way or another: https://github.com/facebook/hhvm

> If you have hundreds of millions of daily active users then needing to write a compiler isn't the end of the world.

It's not the end of the world because they have deep pockets and a problem domain where preserving the interface (I.e., keep everything still running on PHP) and optimizing the infrastructure that provides it is more cost effective and least disruptive than switching to a tech stack that is more performant.

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