[Uberphallus]

> It was slower with the fewer threads, and giving it more threads made it even slower. Celebrating this as awesome efficiency is..."interesting".

With 1 to 4 process increase in 4 cores there's basically no granularity, at 3 there's not enough concurrency, and at 4 there's too much, choking the PostgreSQL process.

Whereas 1 to 16 blocking process increase allow for more granularity ramp up and leave the (almost) exact room for the PSQL process to do its thing before performance degrades.

That would be solved having the DB on a separate host to isolate this effect, and what happens in literally any non-dev environment.

And that's leaving asid the fact that 16 processes use roughly 4 times as much memory as 4, meaning async is cheaper to scale horizontally overall.