(Although the sibling post pointing to my postgres connection scalability post is right - processes are not the major bottleneck at the moment, and certainly not with < PG 14)
Yeah I agree wholeheartedly. What I was trying to get across was that simply s/processes/threads isn't going to make a massive difference to postgres if that was the only change you were to make.
Your analysis seems pretty on-point with what I expected, i.e snapshot scalability and other postgres specific arch being the major bottlenecks for higher connection counts.
FWIW, a good chunk of the snapshot scalability changes are in PG 14, so the situation has gone a bit further towards s/processes/threads/ being the primary bottleneck. It depends quite a bit on whether you're write-mostly (bottlenecks almost completely unrelated to processes vs threads) or read-mostly. And in the latter case whether it's a context switch heavy workload (processes vs threads may be a significant factor), or not (processes vs threads can be a significant factor, but less likely).
