To: Peter Eisentraut <peter_e@gmx.net>
cc: Robert Haas <robertmhaas@gmail.com>,
 Josh Kupershmidt <schmiddy@gmail.com>,
	pgsql-docs@postgresql.org
Subject: Re: Documenting removal of nonnullvalue() and friends 
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Comments: In-reply-to Peter Eisentraut <peter_e@gmx.net>
	message dated "Fri, 15 Oct 2010 18:26:59 +0300"
Date: Fri, 15 Oct 2010 11:40:53 -0400
Message-ID: <21407.1287157253@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>

Peter Eisentraut <peter_e@gmx.net> writes:
> On tor, 2010-10-14 at 19:17 -0400, Robert Haas wrote:
>> Part of the problem, I think, is that people don't necessarily find
>> this stuff via the documentation.  They fire up psql or pgAdmin and
>> start typing backslash commands.  They see something good, so they use
>> it.  How are they to know it's undocumented?

> This could possibly be addressed if we more diligently maintained the
> system catalogs comments, and then possibly default the comments of
> undocumented objects to "internal object, don't use".

I thought about this a bit more last night.  It's certainly true that
a lot of "internal" functions have comments that don't suggest that
they're not meant to be used directly.  What I think would be a good
plan for functions that underlie operators is that we move any useful
comments from pg_proc to pg_operator, and then install a comment in
pg_proc that says "implementation of operator +" (or whatever the
operator name is).  This will not only let people know that they should
use an operator instead, but which one to use, when they find the
function via \df.

I believe that there are a few cases where we document both the operator
and the equivalent function, so in those cases both should have the
regular comment.

The same sort of approach could be used for functions that are meant as
aggregate support, if they don't have any real stand-alone use.  I think
most of the other categories of support functions are already pretty
obviously internal, if there even are any that don't have "internal"
arguments.

If that sounds like a reasonable plan, I'm willing to have a go at it
after the commitfest closes.

			regards, tom lane