I agree and if polling was the only consideration then this would mitigate the issue. Admittedly I didn't cover this as much in my article but there's also a lot of other flexibility afforded by a good message queue around delivery strategies, consumption strategies, error handling, etc that you would have to do much more manually and painfully trying to shoehorn it into a database (even a good one). I am not saying PostgreSQL notify commands are not useful for certain tasks, just encouraging people to understand the tools available and pick the right one for the job.