Re: proposal: a validator for configuration files

Florian Pflug <fgp@phlo.org> writes:
> The code the actually implements the "check settings first, apply later" logic
> isn't easy to read. Now, assume that this code has a bug. Then, with your
> patch applied, we might end up with the postmaster applying a setting (because
> it didn't abort early) but the backend ignoring it (because they did abort early).
> This is obviously bad. Depending on the setting, the consequences may range
> from slightly confusing behaviour to outright crashes I guess...

This is already known to happen: there are cases where the postmaster
and a backend can come to different conclusions about whether a setting
is valid (eg, because it depends on database encoding).  Whether that's
a bug or not isn't completely clear, but if this patch is critically
dependent on the situation never happening, I don't think we can accept
it.
        regards, tom lane