Re: Fix GUC_NO_SHOW_ALL test scenario in 003_check_guc.pl

At Mon, 13 Feb 2023 12:18:07 +0900, Michael Paquier <michael(at)paquier(dot)xyz> wrote in
> On Mon, Feb 13, 2023 at 11:27:58AM +0900, Kyotaro Horiguchi wrote:
> > I think currently the output by --describe-config can be used only for
> > consulting while editing a (possiblly broken) config file. Thus I
> > think it's no use showing GIC_DISALLOW_IN_FILE items there unless we
> > use help_config() for an on-session use.
> >
> > On the other hand, don't we need to remove the condition
> > GUC_NOT_IN_SAMPLE from displayStruct? I think that help_config()
> > should show a value if it is marked as !GUC_DISALLOW_IN_FILE even if
> > it is GUC_NOT_IN_SAMPLE. I'm not sure whether there's any variable
> > that are marked that way, though.
>
> As in marked with GUC_NOT_IN_SAMPLE but not GUC_DISALLOW_IN_FILE?
> There are quite a lot, developer GUCs being one (say
> ignore_invalid_pages). We don't want to list them in the sample file
> so as common users don't play with them, still they make sense if
> listed in a file.

Ah, right. I think I faintly had them in my mind.

> If you add a check meaning that GUC_DISALLOW_IN_FILE implies
> GUC_NOT_IN_SAMPLE, where one change would need to be applied to
> config_file as all the other GUC_DISALLOW_IN_FILE GUCs already do
> that, you could remove GUC_DISALLOW_IN_FILE. However,
> GUC_NOT_IN_SAMPLE should be around to not expose options, we don't
> want common users to know too much about.

Okay, I thought that "postgres --help-config" was a sort of developer
option, but your explanation above makes sense.

> The question about how much people rely on --describe-config these
> days is a good one, so perhaps there could be an argument in removing

Yeah, that the reason for my thought it was a developer option...

> GUC_NOT_IN_SAMPLE from the set. TBH, I would be really surprised that
> anybody able to use a developer option writes an configuration file in
> an incorrect format and needs to use this option, though :)

Hmm. I didn't directly link GUC_NOT_IN_SAMPLE to being a developer
option. But on second thought, it seems that it is. So, the current
code looks good for me now. Thanks for the explanation.

regards.

--
Kyotaro Horiguchi
NTT Open Source Software Center