The fact is that performance oriented organizations optimize everything unless they have math telling them it isn't worth optimizing.
The "weakest link" belief is pure conjecture
Most companies don’t have unlimited budgets. Performance-oriented organizations profile and then spend money where profiling tells them to. Shopify isn’t hiring people to contribute to MySQL or Redis internals. They hired a full team to work on Ruby internals, not just creating YJIT, but also on CRuby’s memory layout, hiring the lead on TruffleRuby, and funding academic programming language research on Ruby.
No company has an infinite budget to “optimize everything”. It is clear where internal performance testing pointed Shopify (at Ruby) and with double digit gains being extracted year after year, their profiling didn’t lie. And other Ruby on Rails shops are seeing similar double digit performance wins, not on fake benchmarks, but on actual page load times and traffic that can be handled by a server.
> Shopify isn’t hiring people to contribute to MySQL or Redis internals
You are not wrong, but the main reason is that contrary to Ruby, MySQL and Redis are used by a lot of huge companies and are themselves owned by companies with full time people on it.
In comparison Ruby is still mostly a volunteer ran project that receive little funding and effort relative to its importance.
As for why trying to make Ruby faster at all in the first place. It's not because it was too slow, it's mostly just that at our scale, the engineering time spent on optimizing the runtime pretty much pays for itself.
But that's nothing specific to Ruby, in most very large software companies you will find similar efforts. e.g. I remember Twitter had a team working on the JVM, etc.
In any case, I am very grateful to Shopify because I think if they decided to switch over to java back in the day, ruby may actually be a mostly dead language by now.
The bizarre part here is that anyone who paint themselves into a corner with ruby, then decide that they need to implement an entire new fancy VM instead of just find targeted bottlenecks and rewriting them in C++. They writing complicated native programs to make a VM that is only 15% faster when they could rewrite specific sections that are slow and speed those up by 200x or more.
Mercedes 2022 https://www.the-race.com/formula-1/mercedes-2022-f1-car-make...
Williams 2019 https://www.autosport.com/f1/news/williams-modifying-front-s...
Ferrari 2018 https://www.autosport.com/f1/news/how-ferraris-formula-1-mir...
But you picking “mirrors” in your analogy makes it sounds like a premature optimization.
The reason why perf isn’t typically an issue with Rails is the design pattern is to leverage heavy caching.
The use of caching is to address the slowness of Ruby.
- database queries
- template rendering
First one because round trip to db + running the query + allocating ORM result objects that otherwise get thrown away.
Second one because allocating a ton of strings that get join'd and thrown away.
> No one disputes that Ruby is slow.
I am, because the blanket statement doesn't make sense without context. Also that view is largely biased by the typical assumption that Ruby == Rails.
In practice though the database is doing most of the work, most of the time so is typically slower than both.
[0] https://en.wikipedia.org/wiki/The_Computer_Language_Benchmar...
https://benchmarksgame-team.pages.debian.net/benchmarksgame/...
Given that the predominate / vast majority use case for Ruby is for web development and Rails being the dominate Ruby web framework ... it's a fair assumption & characterization for people to make that the Ruby == Rails use case.
