
How Three Guys Rebuilt the Foundation of Facebook - protocolon
http://www.wired.com/wiredenterprise/2013/06/facebook-hhvm-saga/all/
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mgkimsal
"Certainly, Facebook has stuck with PHP in large part because it would be an
even bigger task to rewrite the entire site in another language. It’s called
The Legacy Problem. “Eventually, you get to a size where it’s not feasible to
rewrite it all,” says Paroksi."

They're not going to rewrite all of the PHP code to some other language, but
they've effectively got a shim in there in the form of the HHVM. They _could_
introduce new aspects to the language via their VM, giving new ways to solve
problems with new code/extensions but without sacrificing backwards
compatibility. I will not be surprised if this evolves from Facebook in the
next few years. What they produce may never leave Facebook's internal users
(beyond what the HHVM exposes in its open source incarnation) but it may end
up being a necessary way forward.

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ufmace
I always wondered why they don't do a more traditional web services-style
rewrite. Break the site up into a smaller and smaller services first, then
start rewriting individual services in Java or C++ or whatever. Pound away at
it for a while, and eventually you'll have the whole site rewritten and
refactored in a much more maintainable way.

~~~
bobosha
"We do these things not because they are easy, but because they are hard"
-John F. Kennedy

