The problem with that logic is that it’s pervasive: people have that same attitude everywhere even if no IO is being done. That’s how we get multi gigabyte processes.

The whole language (and Rails) also pushes you towards a less efficient path. For instance you’re probably iterating over those six plans and inserting them individually in the DB. Another approach would’ve been to accumulate all of them in memory then build and perform a single query. That’s not something people really consider because it’s “micro” optimization and makes the code look worse. But if you miss out on hundreds of these micro optimizations then you get a worse system.

In a general sense optimizing Ruby is indeed futile: any optimization is dwarfed by just choosing a different language.

I say all this as someone who has worked with it for two decades, I like the language, it’s just laughably inefficient.