alt Hacker NewsYour high level buckets are languages but the constraints you list are usage patterns.
You can build applications in any language that have many short-lived transactions in single connections or a few huge, blocking one, or anything in between.
The former case is a good one for PGBouncer (it can interleave transactions) and the latter isn’t (it can’t do much about your three minute long BEGIN…COMMIT). Neither has to do with the language.
They addressed this though? I suspect you are unfamiliar with the GIL in python. The reason for a language distinction is because, as OP says: "As it's much easier to share a connection pool locally".
This may change vaguely soon, but right now you typically scale python apps by starting multiple python processes, while for Java you can just add threads. Python processes can't share a thread pool among all of them, while Java can.