Date: Mon, 1 Aug 2022 09:52:57 -0500
From: Justin Pryzby <pryzby@telsasoft.com>
To: =?iso-8859-1?Q?=C1lvaro?= Herrera <alvherre@alvh.no-ip.org>
Cc: Peter Eisentraut <peter.eisentraut@enterprisedb.com>,
	Amit Langote <amitlangote09@gmail.com>,
	Japin Li <japinli@hotmail.com>, Zhihong Yu <zyu@yugabyte.com>,
	Simon Riggs <simon.riggs@enterprisedb.com>,
	pgsql-hackers@lists.postgresql.org,
	Tomas Vondra <tomas.vondra@enterprisedb.com>,
	Daniel Westermann <dwe@dbi-services.com>,
	Erik Rijkers <er@xs4all.nl>,
	Jaime Casanova <jcasanov@systemguards.com.ec>,
	Andres Freund <andres@anarazel.de>
Subject: Re: support for MERGE
Message-ID: <20220801145257.GA15006@telsasoft.com>
References: <202206011528.j2i6c64v7yqs@alvherre.pgsql>
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On Tue, Jun 14, 2022 at 11:27:06AM +0200, Álvaro Herrera wrote:
> @@ -448,9 +448,9 @@ COMMIT;
>      and execute the first one that succeeds.
>      If <command>MERGE</command> attempts an <command>INSERT</command>
>      and a unique index is present and a duplicate row is concurrently
> -    inserted, then a uniqueness violation is raised.
> -    <command>MERGE</command> does not attempt to avoid the
> -    error by executing an <command>UPDATE</command>.
> +    inserted, then a uniqueness violation error is raised;
> +    <command>MERGE</command> does not attempt to avoid such
> +    errors by evaluating <literal>MATCHED</literal> conditions.

This was a portion of a chang that was committed as ffffeebf2.

But I don't understand why this changed from "does not attempt to avoid the
error by executing an <command>UPDATE</command>." to "...by evaluating
<literal>MATCHED</literal> conditions."

Maybe it means to say "..by re-starting evaluation of match conditions".

Sorry to re-raise this 6 weeks later..

-- 
Justin