Interesting article. Not sure that the conclusion is all that solid though: "I quantified that 1 C++ server is roughly equivalent to 40 load-balanced python servers for raw computational power based on our HTTP benchmarking. Thus using C++ can really squeeze all the computational juice out of the underlying hardware to save 1/40 off server costs."
Well, for this particular start-up, I think c++ was an excellent choice (especially as they already knew c++!) -- but what if you could still run the service on a single service with python? You would still need 2-3 servers with the c++ version (failover, test etc).
Or it might turn out that for production load, you'd need 10 python server-instances. Sure, one server could handle this with c++ -- but you're not actually saving 39/40, you're only saving 9/10, because you didn't need "the full 40".
Not to mention, that it seems unlikely that the http request stuff is the limiting factor in a distributed OLAP system. So you might do 100 "OLAPS/s", and have them easily served by a 40Kreq/s python service.
"I guess we could have written it in Python to start off with but, economically, it would be a wastage of labor cost and time because, at some stage, we would have to scrap it for a C++ version to get the performance we need. The Python code will have no economic value once scrapped."
As mentioned, I think c++ was an excellent choice, but the above assumes they'd have to rewrite the entire system in c++, and scrap all the python. Granted, if you don't know python, but do know c++ very well -- it's doubtful that it would be faster to prototype in python than to just use c++.
But if (wild guesstimate) you could get 90% of the features, at 10% the loc/dependencies in python -- who's to say that wouldn't make sense? Maybe parts could be done in c/c++, or the project could move to pypy for enough of a speedup that no complete rewrite would be needed... etc.
Overall though, I really think this is a great illustration that high-performance compiled languages offer great performance, and can be rather pleasant to work with.
Absolutely excellent article. I always keep C++ at the back of my mind in case I need it some day, so I think the list of libraries they used will be useful for me in the future. Thanks.
