The notifications are queued in the system, so there's no guarantee it's going to be instantly. Anyway, they are usually quite fast, for sure faster than the work on the database.
If you want to be 100% sure, just set a flag somewhere and when you receive the notification, check that the databases is reloaded.
Anyway, I'm just thinking that even if the notification is received after the reload of the database, because the notification are queued, the hide loader notification will come right after the first one, so there would be nothing to worry about.