Received: from malur.postgresql.org ([217.196.149.56])
	by arkaria.postgresql.org with esmtps  (TLS1.3) tls
 TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
	(Exim 4.96)
	(envelope-from <pgsql-docs-owner+archive@lists.postgresql.org>)
	id 1w53JC-002qWn-2F
	for pgsql-docs@arkaria.postgresql.org;
	Tue, 24 Mar 2026 15:04:42 +0000
Received: from localhost ([127.0.0.1] helo=malur.postgresql.org)
	by malur.postgresql.org with esmtp (Exim 4.96)
	(envelope-from <pgsql-docs-owner+archive@lists.postgresql.org>)
	id 1w53JB-007Qn9-0K
	for pgsql-docs@arkaria.postgresql.org;
	Tue, 24 Mar 2026 15:04:41 +0000
Received: from makus.postgresql.org ([2001:4800:3e1:1::229])
	by malur.postgresql.org with esmtps  (TLS1.3) tls
 TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
	(Exim 4.96)
	(envelope-from <bruce@momjian.us>)
	id 1w53JA-007Qn1-2r
	for pgsql-docs@lists.postgresql.org;
	Tue, 24 Mar 2026 15:04:41 +0000
Received: from momjian.us ([72.94.173.45])
	by makus.postgresql.org with esmtps  (TLS1.3) tls
 TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
	(Exim 4.98.2)
	(envelope-from <bruce@momjian.us>)
	id 1w53J9-00000000o71-28YK
	for pgsql-docs@lists.postgresql.org;
	Tue, 24 Mar 2026 15:04:40 +0000
DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=momjian.us;
	s=2026010100; h=In-Reply-To:Content-Transfer-Encoding:Content-Type:
	MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To:
	Content-ID:Content-Description;
	bh=ab272EwuYPRr3Yc6LENUp1pZXhVSd7ykn6OXKNM+bPU=; b=xqYi+Nbv5NlQ3SnZCmSskN22W5
	l7m+YDq4pk02BB8xF8Rt8WCFRqPoeQ2EVojIXjuw4M1sT7MRZHT/aAX/7jlm+I7q+S6xkewVhtw5X
	oqflbYAvvG9Z5JgU59FUbkk5tP/wCtSYPiprNRJLR8IwiTHfj/h0sRCIWgLBYoCaLbbGTW8688tQJ
	fU0BZtQGFwhvJ4ERLDWQ0W/Too9KWvNKrHgJfjOs6HAEFJlZztQXRK9idwOSZbdMpP9xKrnZggkr0
	em3YYnc4013MOfU8N8UO28uUIx9xax6VKID+eW09IICu2xDOYjwZVAP6a0V4UuGs4XhDhl0VbwTB2
	/uV/oc1w==;
Received: from bruce by momjian.us with local (Exim 4.98.2)
	(envelope-from <bruce@momjian.us>)
	id 1w53J8-00000003Nvs-0zT9;
	Tue, 24 Mar 2026 11:04:38 -0400
Date: Tue, 24 Mar 2026 11:04:38 -0400
From: Bruce Momjian <bruce@momjian.us>
To: Nikolay Samokhvalov <nik@postgres.ai>
Cc: Laurenz Albe <laurenz.albe@cybertec.at>,
	pgsql-docs@lists.postgresql.org
Subject: Re: [PATCH] Doc: clarify that pg_upgrade statistics transfer works
 cross-version
Message-ID: <acKoBql5eQWpQH4N@momjian.us>
References: 
 <CAM527d_Qt9ZGt99vgTaidfObRiDH0R5F_uEfum9zHeZbc+LwCQ@mail.gmail.com>
 <1a7d3c03e6169e6340f9d77667433fd0cc5f5897.camel@cybertec.at>
 <CAM527d89GmcMV5GD2PXS-a3ay3YE-HVSwV4NT0_o2ySf_5v8Kw@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
In-Reply-To: 
 <CAM527d89GmcMV5GD2PXS-a3ay3YE-HVSwV4NT0_o2ySf_5v8Kw@mail.gmail.com>
List-Id: <pgsql-docs.lists.postgresql.org>
List-Help: <https://lists.postgresql.org/manage/>
List-Subscribe: <https://lists.postgresql.org/manage/>
List-Post: <mailto:pgsql-docs@lists.postgresql.org>
List-Owner: <mailto:pgsql-docs-owner@lists.postgresql.org>
List-Archive: <https://www.postgresql.org/list/pgsql-docs>
Archived-At: 
 <https://www.postgresql.org/message-id/acKoBql5eQWpQH4N%40momjian.us>
Precedence: bulk

On Tue, Mar 24, 2026 at 05:36:42AM -0700, Nikolay Samokhvalov wrote:
> On Mon, Mar 23, 2026 at 23:59 Laurenz Albe <laurenz.albe@cybertec.at> wrote:
> ...
> 
>     I think that your patch offers too much detail,
>     like from which relations the statistics are extracted.  Anybody
>     who wants to know that level of detail probably has to read the
>     source code anyway.
> 
>     How about adding a simple remark, like
> 
>     --- a/doc/src/sgml/ref/pgupgrade.sgml
>     +++ b/doc/src/sgml/ref/pgupgrade.sgml
>     @@ -837,6 +837,8 @@ psql --username=postgres --file=script.sql postgres
>           all statistics, such as those created explicitly with
>           <xref linkend="sql-createstatistics"/>, custom statistics added by
>           an extension, or statistics collected by the cumulative statistics
>     system.
>     +     Transferring optimizer statistics works regardless of the old
>     cluster's
>     +     major version.
>          </para>
> 
>          <para>
> 
> 
> That would work too -- my goal was just to resolve confusion.

I was under the same impression --- that it only worked with upgrades
_from_ PG 18 and later.  However, I can't find any documentation on this
limitation, so why did so many think this was true?  I don't think
adding anything to the docs is the right approach.

-- 
  Bruce Momjian  <bruce@momjian.us>        https://momjian.us
  EDB                                      https://enterprisedb.com

  Do not let urgent matters crowd out time for investment in the future.