Re: pg_comments (was: Allow \dd to show constraint comments)

On Wed, Oct 12, 2011 at 2:49 PM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
> So, I think the critical question for this patch is "do we want
> this?".

Yep. Or put another way, are the gains worth having another system
view we'll have to maintain forever?

> Tom didn't like it,

In [1], Tom seemed to be mainly angling for fixing up psql instead,
which has been done now. I didn't see a specific reason against adding
the view, other than it "cannot be changed without an initdb". That's
a valid concern of course, but it applies equally well to other system
views.

[snip]
> On the third hand, Josh's previous batch of changes to clean up
> psql's behavior in this area are clearly a huge improvement: you can
> now display the comment for nearly anything by running the appropriate
> \d<foo> command for whatever the object type is.  So ... is this still
> a good idea, or should we just forget about it?

I think this question is a part of a broader concern, namely do we
want to create and support system views for easier access to
information which is already available in different ways through psql
commands, or by manually digging around in the catalogs? I believe
there are at least several examples of existing views we maintain
which are very similar to pg_comments: pg_seclabel seems quite
similar, for instance.

Josh

--
[1] http://archives.postgresql.org/pgsql-hackers/2010-09/msg01081.php