Feedback-ID: ie3de48e3:Fastmail
Date: Thu, 28 May 2026 20:35:27 +0200
From: =?utf-8?Q?=C3=81lvaro?= Herrera <alvherre@kurilemu.de>
To: Chao Li <li.evan.chao@gmail.com>
Cc: Baji Shaik <baji.pgdev@gmail.com>, pgsql-hackers@lists.postgresql.org
Subject: Re: [PATCH] Improve REPACK (CONCURRENTLY) error messages for
 unsupported configurations
Message-ID: <ahiKMDxJ-G4bAy8Q@alvherre.pgsql>
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On 2026-May-27, Chao Li wrote:

> >  0002 -- check_concurrent_repack_requirements() reports the same
> >          generic "no identity index" error for several distinct
> >          cases, two of which are misleading: REPLICA IDENTITY FULL
> >          (which is set, but the hint says there is no identity), and
> >          a deferrable PK as the only identity (skipped per commit
> >          832e220d99a, but the hint suggests adding an index that
> >          already exists).  Distinguish these cases.
> 
> When I was working on 832e220d99a, I actually considered for more
> detailed error messages, but I ended up giving up. I think we should
> be careful about adding more branches here unless the existing message
> is causing significant confusion in practice.

I pushed this one too (well, something close to it anyway), because I
think the replica identity issue could be an (unnecessary) usability
tripwire.

I'm curious to know why you gave up on this, if you want to share more.

Thanks both,

-- 
Álvaro Herrera         PostgreSQL Developer  —  https://www.EnterpriseDB.com/
Voy a acabar con todos los humanos / con los humanos yo acabaré
voy a acabar con todos (bis) / con todos los humanos acabaré ¡acabaré! (Bender)