Re: COMMENT ON INDEX silently fails

On Fri, Sep 30, 2016 at 08:49:01AM -0400, Tom Lane wrote:
> Michael Herold <quabla@hemio.de> writes:
> > The statement
> > COMMENT ON INDEX object_name IS '...'
> > does not fail if object_name is a table constraint. However, it does
> > not seem to have any effect.
>
> Sure it does.
>
> regression=# create table foo (f1 int primary key);
> CREATE TABLE
> regression=# \d foo
>       Table "public.foo"
>  Column |  Type   | Modifiers
> --------+---------+-----------
>  f1     | integer | not null
> Indexes:
>     "foo_pkey" PRIMARY KEY, btree (f1)
>
> regression=# select * from pg_description where objoid = 'foo_pkey'::regclass;
>  objoid | classoid | objsubid | description
> --------+----------+----------+-------------
> (0 rows)
>
> regression=# comment on index foo_pkey is 'test comment';
> COMMENT
> regression=# select * from pg_description where objoid = 'foo_pkey'::regclass;
>  objoid | classoid | objsubid | description
> --------+----------+----------+--------------
>  478892 |     1259 |        0 | test comment
> (1 row)
>
> I suspect you were expecting the comment to be displayed in some place it
> isn't, but that's hard to discuss intelligently when you didn't say where
> you expected it to show up.  It is there in, eg, \di+ output:
>
> regression=# \di+ foo_pkey
>                             List of relations
>  Schema |   Name   | Type  |  Owner   | Table |    Size    | Description
> --------+----------+-------+----------+-------+------------+--------------
>  public | foo_pkey | index | postgres | foo   | 8192 bytes | test comment
> (1 row)

It's not in the \df+ output, where a reasonable person could expect it
to show up.  Is this worth a patch for 10?

Best,
David.
--
David Fetter <david(at)fetter(dot)org> http://fetter.org/
Phone: +1 415 235 3778  AIM: dfetter666  Yahoo!: dfetter
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