Date: Sun, 21 Mar 2021 13:14:20 -0500
From: Justin Pryzby <pryzby@telsasoft.com>
To: Alvaro Herrera <alvherre@alvh.no-ip.org>
Cc: Amit Langote <amitlangote09@gmail.com>,
	pgsql-hackers@lists.postgresql.org
Subject: Re: ALTER TABLE .. DETACH PARTITION CONCURRENTLY
Message-ID: <20210321181420.GC11765@telsasoft.com>
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On Sun, Mar 21, 2021 at 03:01:15PM -0300, Alvaro Herrera wrote:
> > But note that it doesn't check if an existing constraint "implies" the new
> > constraint - maybe it should.
> 
> Hm, I'm not sure I want to do that, because that means that if I later
> have to attach the partition again with the same partition bounds, then
> I might have to incur a scan to recheck the constraint.  I think we want
> to make the new constraint be as tight as possible ...

The ATTACH PARTITION checks if any existing constraint impilies the (proposed)
partition bounds, not just if constraints are equal.  So I'm suggesting to do
the same here.

-- 
Justin