Re: BUG #18336: Inconsistency in PostgreSQL 16 Documentation for SHOW Command

On Sat, Aug 17, 2024 at 02:12:40PM -0400, Tom Lane wrote:
> Imran Zaheer <imran.zhir@gmail.com> writes:
> > The website[1] still shows the redundant LC_COLLATE & LC_CTYPE params.
> > Are we planning to update them?
> 
> This patch seems to have fallen through the cracks.  I thought

I had kept this thread in my mailbox from February.

> I'd go apply it, but on closer inspection the cross-reference

I was trying to apply Peter Eisentraut's patch when gitmaster stopped
working.

> to SET seems to indicate we have some more work to do.
> That's because set.sgml has its own list of "special" names.
> It'd be fine if SHOW recognized exactly the same list of special
> names, but it seems to recognize only some of them:
> 
> regression=# set time zone 'America/New_York';
> SET
> regression=# show time zone;
>      TimeZone     
> ------------------
>  America/New_York
> (1 row)
> regression=# set names 'LATIN1';
> SET
> regression=# show names;
> ERROR:  unrecognized configuration parameter "names"
> 
> Digging in gram.y, I see that VariableShowStmt actually has these options:
> 
>             SHOW var_name
>             | SHOW TIME ZONE
>             | SHOW TRANSACTION ISOLATION LEVEL
>             | SHOW SESSION AUTHORIZATION
>             | SHOW ALL
> 
> which is a subset of the special cases in VariableSetStmt (many
> of which don't seem to be documented anywhere, although I suppose
> most or all are derived from the SQL spec).  I wonder if we ought
> to try to make that more systematic.  I don't see a really good
> reason why SHOW shouldn't have exactly the same list of special
> target-name syntaxes as SET.

Agredd.

> In short: we might end up applying exactly this patch to show.sgml,
> but we'd have to do some work elsewhere to make the cross-ref to
> set.sgml not still be a lie.  Maybe we should go ahead and commit
> it as-is anyway, since it's better than what we have.

I think we should apply what Peter supplied, and then we can do a
follow-up patch to synchronize.

-- 
  Bruce Momjian  <bruce@momjian.us>        https://momjian.us
  EDB                                      https://enterprisedb.com

  Only you can decide what is important to you.