On Sat, Jul 16, 2011 at 12:49 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> I wrote:
>> Josh Kupershmidt <schmiddy@gmail.com> writes:
>>> What's the Description displayed in that table?
>
>> What it ought to be is the comment (if any) attached to the index's
>> column. Up through 8.4 this worked as expected, but in 9.0 and up
>> somebody seems to have disallowed comments on index columns. Not
>> sure how carefully that was thought through.
>
> After a bit of review of the archives, the somebody was me:
> http://git.postgresql.org/gitweb/?p=postgresql.git&a=commitdiff&h=b7d67954456f15762c04e5269b64adc88dcd0860
>
> and this thread was the discussion about it:
> http://archives.postgresql.org/pgsql-hackers/2009-12/msg01982.php
>
> It looks like we thought about pg_dump, but did not think about psql.
>
> I think it might be reasonable to remove the Description column from
> \d+ output for indexes and sequences, on the grounds that (1) it's
> useless against 9.x servers, and (2) for those relkinds we add other
> columns and so the horizontal space is precious.
Yeah, I think that's very reasonable. We're talking about changing
this in 9.2, which will be the third release since that functionality
was deprecated. Considering that the functionality is so minor that
there may be no one using it anyway, that seems more than generous.
> We could also consider showing Description only when talking to a
> pre-9.0 server; but that's going to render the code even more
> spaghetti-ish, and the value seems pretty limited.
I don't think we need to do that. Backward compatibility is good, but
insisting that a 9.2 psql has to produce exactly the same output on an
8.3 server than an 8.3 psql would have done seems like it would be
taking things too far. We should try to make it work and be useful,
but we shouldn't slavishly replicate obsolete functionality of
doubtful utility.
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company
