I've worked on a webapp under serious load, and I think he's right.
You're correct that database queries and resource bottlenecks are the usual problems for web application scaling, but even taking that into account, I've had more than one problem that was caused by the simple fact that Ruby is a dog of a language. Python is better, but only just so. Perl is faster than both, but still nowhere near as fast as a C++ program.
But let's ignore execution speed, since one can make a reasonable argument that even the slowest scripting language can saturate the network I/O on modern hardware. I think I'd still consider using a compiled language, because the type-safety and compile-time guarantees of a statically typed language would go a long way toward eliminating a huge class of silly bugs that we deal with on a daily basis. That's developer time in the bank.
> I think I'd still consider using a compiled language, because the type-safety and compile-time guarantees of a statically typed language would go a long way toward eliminating a huge class of silly bugs that we deal with on a daily basis.
Not all compiled languages are statically typed.
> That's developer time in the bank.
And the time spent in the edit, compile, test, run, cycle? I'd think there's more developer time in the bank if I can edit, test, run.
No, not all compiled languages are statically typed. I wouldn't use those languages.
The time spent compiling is a red herring. I know that I've spent dozens of hours chasing down weird runtime bugs in Ruby that a C++ compiler would have caught for me during static analysis. That time more than makes up for the 15 minutes a day I might spend waiting on a compiler (I waste more than 15 minutes a day on coffee breaks!)
You're correct that database queries and resource bottlenecks are the usual problems for web application scaling, but even taking that into account, I've had more than one problem that was caused by the simple fact that Ruby is a dog of a language. Python is better, but only just so. Perl is faster than both, but still nowhere near as fast as a C++ program.
But let's ignore execution speed, since one can make a reasonable argument that even the slowest scripting language can saturate the network I/O on modern hardware. I think I'd still consider using a compiled language, because the type-safety and compile-time guarantees of a statically typed language would go a long way toward eliminating a huge class of silly bugs that we deal with on a daily basis. That's developer time in the bank.