I can go either way on this topic, however for the sake of engineering lets invert this problem a little bit and take it upstream. When your entire system is th

I can go either way on this topic, however for the sake of engineering lets invert this problem a little bit and take it upstream. When your entire system is thread based (unique thread assigned to a given request) then even with pgBouncer you end up standing in line to wait for the connection. Most IO heavy application servers now just have the threads waiting for DB connections cause you just scaled (increased number of instances) the application servers for the load. This thread waiting could have been done on web server level as well, allowing one to manage DB connections in application server instead of adding pgBouncer. tldr; a lot of times pgBouncer is just a duct taped solution to upstream problem. You can easily have web scale (?) application without pgBouncer if you application logic allows it and you pick a applicable design choice.