> it doesn't really make much sense to prioritize this inside the database server itself.
I wouldn't go that far. There's a lot of things that are hard to do within an external pooler, unless the pooler uses a 1:1 connection model. Leading to most setups using 1:1 connection pooling methods. Which in turn puts pressure on postgres to handle large numbers of connections gracefully.
Would an app-side ORM that has built-in connection pooling + PG14 (w/ connection scalability improvements) generally benefit from a connection pooler like Odyssey/PgBouncer, either server-side or app-side, when the number of app servers is low (<5-10)?
As a data point FWIW, I have operated a PG11 cluster (on RDS), client-side pooling only, with 300-450 app servers and max_connections=2000-3000 (can’t remember), and didn’t observe significant backend resource contention or performance degradation, just a memory cost linear to number of connections,
Unless the app servers are particularly large, or the app-side ORM connection pool doesn't work well (e.g. because the number of concurrent requests changes sufficiently over time that thread/process count constantly changes), I'd guess not. But without knowing a bit more it's hard to say.
I wouldn't go that far. There's a lot of things that are hard to do within an external pooler, unless the pooler uses a 1:1 connection model. Leading to most setups using 1:1 connection pooling methods. Which in turn puts pressure on postgres to handle large numbers of connections gracefully.