Earlier quoted context omitted.
Collect directly from shard-level prometheus then aggregate using /federate at another level. That’s how thanos also works afaik
This still requires the query to fit on a single node at some point unless you're doing multi-level aggregation. Monarch does that. Being able to push expensive, highly-parallelizable aspects of the query down into the leaves is a massive benefit.
Yep, in theory it’s great if you can afford a team of highly qualified engs to run it like google and dealing with huge metrics. In practice I found it was not hard to crash a monarch mixer (at least some years ago) + most orgs won’t be able to afford nor take advantage of it