Comment by broken_broken_

I have implemented polling against a cluster of mixed mariadb/mysql databases which do not offer listen/notify. It was a pain in the neck to get right.

- The batch size needs to be adaptative for performance, latency, and recovering smoothly after downtime.

- The polling timeouts, frequency etc the same.

- You need to avoid hysteresis.

- You want to be super careful about not disturbing the main application by placing heavy load on the database or accidentally locking tables/rows

- You likely want multiple distributed workers in case of a network partition to keep handling events

It’s hard to get right especially when the databases at the time did not support SKIP LOCKED.

In retrospect I wish I had listened to the WAL. Much easier.