I can't speak for how they do it, but when your worker polls the table and finds no rows, you will sleep. While sleeping, you can also LISTEN on a channel (and

I can't speak for how they do it, but when your worker polls the table and finds no rows, you will sleep. While sleeping, you can also LISTEN on a channel (and if you get a message, you abort your sleep). Then, whenever you write a new job to the queue, you also do a NOTIFY on the same channel. This lets you keep latency low while still polling relatively infrequently. NOTIFY is actually transactional which makes this approach even better (the LISTENer won't be notified until the NOTIFY transaction commits)