I assumed it would work as a regular pub/sub pattern where you get notified when some event happens. However, in the attached example, they still poll the database every half second. I'm not sure I understand the idea.
> JDBC driver cannot receive asynchronous notifications.
Maybe their example is limited by the choice of client library.
This might be a better example? https://tapoueh.org/blog/2018/07/postgresql-listen-notify/
Or the offical postgres docs are:
https://www.postgresql.org/docs/14/sql-notify.html
Quite strange that this specific driver didn't support asynchronous notifications: if you have to poll the database anyway, there's no much difference between doing it without listen/notify support, I guess.