> What if instead of that you’d actually compile all JS files once to some sensible format that would allow you to do lookup of variable in any scope?

An enormous amount of javascript and sourcemaps we are dealing with are one hit wonders and/or need fetching from external sources. We have no impact on the format of the data there and as mentioned converting it once into a different format does not at all help here.

> I bet you don’t need full debug info as in complete DWARF data.

Correct, which is why as part of making processing of iOS symbols faster we wrote our own file format that we can efficiently mmap. It's 10% of the size of the average DWARF, gives us all the information we want without parsing or complex processing (https://github.com/getsentry/symbolic/tree/master/symcache).

The reason I'm writing this is because as you can see we're very far away from "just handling boring events". There is a ton of complexity that goes into it. We're not idiots here ;)

> Shards can be rebalanced.

That changes nothing about the fact, that unless we have to introduce any form of affinity we are better off writing faster code that does not depend on it.