Scheduler option into Firebird ?

DY> Isn't it what e.g. cron is for? ;-)

Roman:
BTW, I do not agree to this. I believe that something like

CREATE TASK {AT | PERIODICALLY }
AS BEGIN
...
END

is much more simpler way to add task compared to creating a script and
adding a cron job to execute an SQL script. How to add this feature to
ClassicServer is another question (probably will not be an issue for
Firebird 3.0). Under which account with which rights to execute it, that one
more question to answer.

But that's my personal opinion.

and Jim's response:

Netfrastructure has such a feature. For better or worse, the schedule is expressed in CRON format extended with seconds. There are two schedulers, one for system tasks and one for user tasks. System tasks are things like the memory scavenger and the Java garbage collector. User tasks are used for replication, calendar notification, report generation, backups, etc.
A major difference between Netfrastructure and Firebird, of course, is that Netfrastructure has an internal Java Virtual Machine that the scheduler uses for scheduler wakeups. In the Firebird context, I don't think stored procedures have enough computational power to be as useful, but it would be a start.

As for rights, the solution is simple. A secheduled procedure runs with the rights of the user who scheduled it.