Re: [PATCH] Stop ALTER SYSTEM from making bad assumptions

On Mon, Aug 5, 2019 at 2:29 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Robert Haas <robertmhaas@gmail.com> writes:
> > All we need to do to resolve this issue is have Tom commit his patch.
>
> I think Stephen is not being unreasonable to suggest that we need some
> documentation about what external tools may safely do to pg.auto.conf.
> So somebody's got to write that.

I mean, really?  We're going to document that if you want to add a
setting to the file, you can just append it, but that if you find
yourself desirous of appending so many settings that the entire disk
will fill up, you should maybe reconsider? Perhaps I'm being mean
here, but that seems like it's straight out of the
blinding-flashes-of-the-obvious department.

If we were going to adopt Stephen's proposed rule that you must remove
duplicates or be punished later with an annoying WARNING, I would
agree that it ought to be documented, because I believe many people
would find that a POLA violation.  And to be clear, I'm not objecting
to a sentence someplace that says that duplicates in
postgresql.auto.conf will be ignored and the last value will be used,
same as for any other PostgreSQL configuration file. However, I think
it's highly likely people would have assumed that anyway.