Except it works just fine for RethinkDB because it was designed from the ground up to efficiently send changes from the shards directly to open connections. It'

Except it works just fine for RethinkDB because it was designed from the ground up to efficiently send changes from the shards directly to open connections. It's a design tradeoff postgres didn't make and they get other benefits rethinkdb doesn't have. But for this use case RethinkDB has a distinct architectural efficiency advantage