From: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>
To: Bruce Momjian <bruce@momjian.us>
To: Alvaro Herrera <alvherre@2ndquadrant.com>
Cc: Michael Paquier <michael@paquier.xyz>
Cc: pgsql-hackers <pgsql-hackers@postgresql.org>
Subject: Re: file cloning in pg_upgrade and CREATE DATABASE
Date: Thu, 11 Oct 2018 16:50:50 +0200
Message-ID: <325b5baf-adcc-9954-2a55-d67b4f3155f0@2ndquadrant.com> (raw)
In-Reply-To: <20181010195002.GA7806@momjian.us>
References: <20181003014409.GC2609@paquier.xyz>
<20181003020706.hykmk4vmy6brovoj@alvherre.pgsql>
<20181010195002.GA7806@momjian.us>
On 10/10/2018 21:50, Bruce Momjian wrote:
>> I see. Peter is proposing to have a fourth mode, essentially
>> --transfer-mode=clone-or-copy.
>
> Uh, if you use --link, and the two data directories are on different
> file systems, it fails. No one has ever asked for link-or-copy, so why
> are we considering clone-or-copy? Are we going to need
> link-or-clone-or-copy too? I do realize that clone and copy have
> non-destructive behavior on the old cluster once started, so it does
> make some sense to merge them, unlike link.
I'm OK to get rid of the clone-or-copy mode. I can see the confusion.
The original reason for this behavior was that the Linux implementation
used copy_file_range(), which does clone-or-copy without any way to
control it. But the latest patch doesn't use that anymore, so we don't
really need it, if it's controversial.
--
Peter Eisentraut http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
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To: pgsql-hackers@postgresql.org
Cc: peter.eisentraut@2ndquadrant.com, bruce@momjian.us, alvherre@2ndquadrant.com, michael@paquier.xyz
Subject: Re: file cloning in pg_upgrade and CREATE DATABASE
In-Reply-To: <325b5baf-adcc-9954-2a55-d67b4f3155f0@2ndquadrant.com>
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