Scheduled jobs

I didn't find any documentation mentioning scheduled jobs. I assume there is no such a feature
yet. I would like to implement it if someone helps me with the development process (I am brand new
to OpenSource projects).

Basically the feature should include scheduling function exeution at:
- postmaster startup
- postmaster shutdown
- a specified moment
- a time of the day/month/year
- recurring at a time interval

I know this could be implemented in exernal processes but from an application standpoint it would
be much more consistent if all the database-related functionality is in the database server.
Besides, both Oracle and Microsoft have the feature.

Please advise.

Thanks,
Zlatko

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