The postgres protocol is stateful, which is necessary for multi-statement sessions (and obviously for multi-statement transactions), as well as COPY. Emulating

The postgres protocol is stateful, which is necessary for multi-statement sessions (and obviously for multi-statement transactions), as well as COPY. Emulating it in a stateless protocol is much messier. It's also a lot faster and easier to parse. With HTTP you don't even know how big the request you need to parse is until you've done some parsing.