Message-ID: <1513687278.2428.7.camel@cybertec.at>
Subject: Re: Background worker process
From: Laurenz Albe <laurenz.albe@cybertec.at>
To: "Brandl, Wolfgang" <wolfgang.brandl@brz.gv.at>,
	"pgsql-admin@postgresql.org"
	 <pgsql-admin@postgresql.org>
Date: Tue, 19 Dec 2017 13:41:18 +0100
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Organization: Cybertec
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Wolfgang Brandl wrote:
> We want to start processes controlled by a prostgres table which acts like crontab.
> So we want to start a background worker process which starts the defined functions.
>  
> Is it possible to start from a background worker process a child process with a specific User.

> So this process can only acces the data for his authority. 
> Like a SQL Intrusion with this definition nobody can start a process a Postgres superuser.

You normally do things like that on UNIX-like operating systems by
setting the "setuid" bit on the executable that you want to start
and transferring ownership to the desired user.

There is no other way for a non-root user like "postgres" to start
an executable as a different user.

Your setup seems complicated.
Why don't you have a daemon process running as root outside of PostgreSQL
that regularly checks the table and starts scheduled processes?

Yours,
Laurenz Albe