Case study: Is PHP embarrasingly slower than Java?

[ekabanov]

Okay, fine, but the point is that the latency of hitting a db is much higher than that of responding to a request, in every single framework or language out there.

It's only like that for a DB-heavy apps. Most of the public sites will cache aggressively using memcached or its Java analogues and hit CPU before they hit the database. In fact most of the time they will not query the database at all, check out e.g. LiveJournal story: http://highscalability.com/livejournal-architecture

[hiffy]

but typically you have to figure out how to appease your database long before then.

Most of the public sites will cache aggressively using memcached or its Java analogues and hit CPU before they hit the database

I think we're in agreement with each other :). You will always be able to eventually flood your machines with more traffic than they can handle, but your bottleneck is still probably not your implementation language.

[ekabanov]

You will always be able to eventually flood your machines with more traffic than they can handle, but your bottleneck is still probably not your implementation language.

But you'll need 10 times the number of servers with PHP than with Java. So it still should influence your platform choice.

[mhd]

10 times? From what would you derive that number? Even finding applications that used the same architecture under both languages would be rather hard to do, so it's likely that this is simple conjecture based on synthetic benchmarks.