Date: Fri, 8 Apr 2022 09:07:56 -0700
From: Nathan Bossart <nathandbossart@gmail.com>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Kyotaro Horiguchi <horikyota.ntt@gmail.com>,
	"pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Subject: Re: remove more archiving overhead
Message-ID: <20220408160756.GA1409034@nathanxps13>
References: <20220222011948.GA3850532@nathanxps13>
 <20220222173711.GA3852671@nathanxps13>
 <20220222195229.GA42988@nathanxps13>
 <20220224.141349.1809640551882183816.horikyota.ntt@gmail.com>
 <20220224175553.GA660690@nathanxps13>
 <20220407222327.GA1363808@nathanxps13>
 <CA+TgmoYEkyU_D_ZihWRNWD9qC0sJ5y8gQtPc2YzVNvEzBAtRSA@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: 
 <CA+TgmoYEkyU_D_ZihWRNWD9qC0sJ5y8gQtPc2YzVNvEzBAtRSA@mail.gmail.com>
Archived-At: 
 <https://www.postgresql.org/message-id/20220408160756.GA1409034%40nathanxps13>
Precedence: bulk

On Fri, Apr 08, 2022 at 10:20:27AM -0400, Robert Haas wrote:
> On Thu, Apr 7, 2022 at 6:23 PM Nathan Bossart <nathandbossart@gmail.com> wrote:
>> On Thu, Feb 24, 2022 at 09:55:53AM -0800, Nathan Bossart wrote:
>> > Yes.  I found that a crash at an unfortunate moment can produce multiple
>> > links to the same file in pg_wal, which seemed bad independent of archival.
>> > By fixing that (i.e., switching from durable_rename_excl() to
>> > durable_rename()), we not only avoid this problem, but we also avoid trying
>> > to archive a file the server is concurrently writing.  Then, after a crash,
>> > the WAL file to archive should either not exist (which is handled by the
>> > archiver) or contain the same contents as any preexisting archives.
>>
>> I moved the fix for this to a new thread [0] since I think it should be
>> back-patched.  I've attached a new patch that only contains the part
>> related to reducing archiving overhead.
> 
> While we're now after the feature freeze and thus this will need to
> wait for v16, it looks like a reasonable change to me.

Dang, just missed it.  Thanks for taking a look.

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