Date: Tue, 18 Dec 2018 15:07:07 -0300
From: Alvaro Herrera <alvherre@2ndquadrant.com>
To: Peter Geoghegan <pg@bowt.ie>
Cc: PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Subject: Re: Fixing findDependentObjects()'s dependency on scan order
 (regressions in DROP diagnostic messages)
Message-ID: <20181218180707.id4chuplqoqzypwe@alvherre.pgsql>
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On 2018-Nov-05, Peter Geoghegan wrote:

> I've realized that my patch to make nbtree keys unique by treating
> heap TID as a tie-breaker attribute must use ASC ordering, for reasons
> that I won't go into here. Now that I'm not using DESC ordering, there
> are changes to a small number of DROP...CASCADE messages that leave
> users with something much less useful than what they'll see today --
> see attached patch for full details. Some of these problematic cases
> involve partitioning:

Is there any case of this that doesn't involve DEPENDENCY_INTERNAL_AUTO
entries?  I wonder if I just haven't broken the algorithm when
introducing that, and I worry that we're adding a complicated kludge to
paper over that problem.  Maybe instead of the depcreate contortions we
need to adjust the algorithm to deal with INTERNAL_AUTO objects in a
different way.

-- 
Álvaro Herrera                https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services