See the commit that made it complex: https://github.com/ruby/ruby/commit/9b49ba5a68486e42afd83db4...
It claims 20-50% speedups in some cases.
There's churn that comes with that. Ruby will have code that is ever changing to gain 5%, 10% performance every now and then. You gotta put that on balance: in a language like Go this method would've been ugly from the start but no one would've needed to touch it in 100 years.
Regardless of how slow the language is, the 90/10 rule applies: 90% of the time is spent in 10% of the code. Optimize that 10%! Making the rest of the code faster isn't worth the code quality cost.
Caching is also vastly underutilized, most apps are read-heavy and could serve a significant portion of their requests from some form of caching.
> When there are performance issues, 95% of the times they come from the database, not the language.
Eh, statements like these are always too hand wavy. Resource usage has to do with performance, the DB has no fault in it but the runtime does.
Having worked with Rails a ton there’s a very large overhead. Most apps would see a significant speed up if rewritten in a faster language and framework, with no changes to the DB whatsoever. The amount of memory and CPU expended to the app servers is always significant, often outweighing the DB.
DHH used to say that it didn't matter if Rails was slow because the database was I/O bound anyway. But that was a long time ago. Times have changed considerably. Most especially because DHH now promotes using SQLite, which completely takes the worst I/O offender right out of the picture. Nowadays the language (when it is as slow as Ruby) is most likely to be the problem.
You can use Crystal which is faster that Go
