Event-based scheduling
On many occasions, a calendar will do fine for scheduling jobs. However, there are situations that require an immediate action and which cannot wait for the next activation based on a calendar. An example might be of a user who logs on to the database and then, using a logon trigger, more actions are executed.
Another example could be a situation in which we want a backup server to be utilized to the maximum, but not beyond that. We schedule all the backups independent of each other and have each backup raise an event when ready, which tells the system that another backup can go ahead. By letting the backup jobs wait for an event that essentially flags "there is backup capacity available now", we make sure that a backup does not take longer than needed. We also make sure that the backup system is pushed to the highest throughput.
When we just use a preset date and time to start the backups, chances are that more backups are running at the same time (possibly caused...
