Kevin Brown <kevin@sysexperts.com> writes:
> The goal here is simply to make it obvious to a system administrator where
> the PG data directory that a given postmaster is using resides.
Why would it not be sufficient to add a read-only GUC variable that
tells that? Connect to the postmaster and do "show datadir" and you're
done. (Without this, it's not clear you've made any particular gain
anyway, since "a given postmaster" would typically mean "the one I can
connect to at this port", no?)
In any case I don't see how removing PGDATA would make this more
obvious. You yourself just pointed out that the command-line arguments
of a postmaster aren't necessarily visible through ps; if they're not,
what have you gained in transparency by forbidding PGDATA?
> In any case, I'm not at all opposed to having the backend stuff know
> about PGDATA during development, but for production you should have to
> explicitly specify the data directory on the command line.
If you wish to do things that way, you can; but that doesn't mean that
everyone else should have to do it that way too. If there were a
security or reliability hazard involved, I might agree with taking the
fascist approach, but I see no such hazard here ...
regards, tom lane