Date: Thu, 7 Jul 2022 09:18:25 -0700
From: Nathan Bossart <nathandbossart@gmail.com>
To: David Steele <david@pgmasters.net>
Cc: Robert Haas <robertmhaas@gmail.com>,
	Fujii Masao <masao.fujii@oss.nttdata.com>,
	Kyotaro Horiguchi <horikyota.ntt@gmail.com>,
	"pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Subject: Re: remove more archiving overhead
Message-ID: <20220707161825.GA2205004@nathanxps13>
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On Thu, Jul 07, 2022 at 10:46:23AM -0400, David Steele wrote:
> On 7/7/22 10:37, Robert Haas wrote:
>> On Thu, Jul 7, 2022 at 10:03 AM Fujii Masao <masao.fujii@oss.nttdata.com> wrote:
>> > Thanks for updating the patch. It looks good to me.
>> > Barring any objection, I'm thinking to commit it.
>> 
>> I don't object, but I just started to wonder whether the need to
>> handle re-archiving of the same file cleanly is as well-documented as
>> it ought to be.
> 
> +1, but I don't think that needs to stand in the way of this patch, which
> looks sensible to me as-is. I think that's what you meant, but just wanted
> to be sure.

Yeah, this seems like something that should be documented.  I can pick this
up.  I believe this is an existing problem, but this patch could make it
more likely.

> There are plenty of ways that already-archived WAL might get archived again
> and this is just one of them.

What are some of the others?  I was aware of the case that was fixed in
ff9f111, where we might try to re-archive a file with different contents,
but I'm curious what other ways you've seen this happen.

-- 
Nathan Bossart
Amazon Web Services: https://aws.amazon.com