Feedback-ID: ie3de48e3:Fastmail
Date: Fri, 12 Dec 2025 11:17:30 +0100
From: =?utf-8?Q?=C3=81lvaro?= Herrera <alvherre@kurilemu.de>
To: Mihail Nikalayeu <mihailnikalayeu@gmail.com>
Cc: Michael Paquier <michael@paquier.xyz>, Noah Misch <noah@leadboat.com>,
	PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Subject: Re: Issues with ON CONFLICT UPDATE and REINDEX CONCURRENTLY
Message-ID: <202512121012.ujrcg2acbagu@alvherre.pgsql>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
In-Reply-To: 
 <CADzfLwUFuF+kCBDbmqNUn-4QHrGfgEu5c0v+UMUcfbq5sg4vAA@mail.gmail.com>
Archived-At: 
 <https://www.postgresql.org/message-id/202512121012.ujrcg2acbagu%40alvherre.pgsql>
Precedence: bulk

On 2025-Dec-12, Mihail Nikalayeu wrote:

> Hello, Álvaro!
> 
> On Thu, Dec 11, 2025 at 10:36 PM Álvaro Herrera <alvherre@kurilemu.de> wrote:
> > I just saw a failure in CI for an unrelated patch
> 
> I'll try to dive deeper tomorrow to find a fix, but it feels like we
> are doing something wrong here.

Hmm, this is a good point.

> But currently we are just trying (not the first time already) to make
> sure OUTPUT of the test is EXACTLY equal to some variant.

A low-cost option might be to add alternative expected file(s), which
matches other variant(s).  I think trying to make isolationtester "smart
match" the output might be more complicated than is warranted.

> I am afraid amount of time needed to stabilize such test (in its
> output, not the sense) is not cover potential value of it.

Yeah, could be.

> Also, I imaging someone changing something unrelated (catalog snapshot
> invalidation, for example) and test starts to fail on some rear animal
> once a week.... Ughn.

Another idea might be to rewrite these tests using BackgroundPsql under
the TAP infrastructure.  That's quite a bit more tedious to write, but
we can be more precise on detecting whether some particular error
message was thrown or not.

-- 
Álvaro Herrera         PostgreSQL Developer  —  https://www.EnterpriseDB.com/
"How amazing is that? I call it a night and come back to find that a bug has
been identified and patched while I sleep."                (Robert Davidson)
               http://archives.postgresql.org/pgsql-sql/2006-03/msg00378.php