[thirdusername]

I would refactor your second example into an exists using Arel, because at best the IN will result in the same performance. At worst it will be significant my slower. There are also particular issues with NOT IN and NULL. This is at least true in PG.

I also deal with a lot of scale, the issues people have here doesn’t match my reality. I think people have issues and rather than looking at what is fundamentally happening with their call patterns, they jump to calling out rails itself.

Rails does have some specific issues, but you’d have to go pretty deep to see them and boot times are terrible.