[mwcampbell]

On the topic of Postgres versus MS SQL Server or Oracle, I wonder if any of the newer Postgres-compatible databases, like Cockroach or Materialize, solve the scalability issue you raise with Postgres, while not having quite the stigma of MS SQL Server or (especially) Oracle.

[mike_hearn]

I'm not sure. Postgres itself has good performance but the issue for two-tier architecture is number of simultaneous connections. Postgres uses a process per connection. Something like pgbouncer in front can help with that but then the complexity starts going up again, as pgbouncer limits to some extent what you can do. Obviously if you have enough RAM to service all simultaneously connected clients it's not a problem, and you can scale RAM by just adding RO replicas. You can also set connections to aggressively time out if clients are idle, and the clients can re-establish them on demand, so there's lots that can be done.

But ultimately, a db like SQL Server or Oracle will just let you use lots of connections without breaking a sweat. They're both threaded and fully async, it's a much more efficient model.