pgbouncer runs as a single threaded service, so it ends up getting bottlenecked by some heavy clients on typical server CPUs with low clock speeds.

Sharding/peering pgbouncer works, but it's not perfect.

More significantly for us is that Neon has millions of databases in each region, and thousands get created/destroyed every hour. Managing the pgbouncer config and shared connection pools will be extremely tricky to balance. We have a bunch of logic for this in the proxy I maintain, but not in pgbouncer.

The main intent is to incorporate a pooler directly into our existing proxy service to avoid needing double proxy services. We just need to find the right pooler implementation (and one that works in async Rust)