Re: ALTER SYSTEM vs symlink

* Tom Lane (tgl(at)sss(dot)pgh(dot)pa(dot)us) wrote:
> Andrew Dunstan <andrew(at)dunslane(dot)net> writes:
> > I don't know if this was discussed at the time ALTER SYSTEM was
> > implemented, but I have just discovered that if postgresql.auto.conf is
> > a symlink to a file elsewhere, ALTER SYSTEM will happily break that link
> > and write its own local copy. That strikes me as rather unfriendly. Why
> > not just truncate the file rather than unlink it as it's being
> > rewritten? Even if we don't want to do that a warning in the docs might
> > help users avoid the "mistake" I just made.
>
> Frankly, that behavior strikes me as a good idea. There is no situation,
> IMV, where it's sane to try to put a symlink there.

I tend to agree with this. Where a symlink makes sense for us are cases
where the configuration information is intentionally stored in the
correct directory structure (eg: /etc on Debian/Ubuntu and systems which
follow the FHS), and intended to be user-modifyable. That's not the
case with ALTER SYSTEM.

What this request strikes me as asking for is the same as what I asked
for when this feature was originally going in- there should be a way to
disable it. Allowing changes through ALTER SYSTEM which can result in
the system not being able to start is dangerous and confusing to many.

Thanks!

Stephen