From: Alvaro Herrera <alvherre@alvh.no-ip.org>
To: Bossart, Nathan <bossartn@amazon.com>
Cc: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Cc: andres@anarazel.de <andres@anarazel.de>
Cc: masao.fujii@oss.nttdata.com <masao.fujii@oss.nttdata.com>
Cc: pgsql-hackers@lists.postgresql.org <pgsql-hackers@lists.postgresql.org>
Cc: mengjuan.cmj@alibaba-inc.com <mengjuan.cmj@alibaba-inc.com>
Cc: Jakub.Wartak@tomtom.com <Jakub.Wartak@tomtom.com>
Subject: Re: prevent immature WAL streaming
Date: Fri, 17 Sep 2021 18:22:00 -0300
Message-ID: <202109172122.y3kcil5qhfpy@alvherre.pgsql> (raw)
In-Reply-To: <E063C45C-BD04-44B7-82A1-F7931D92D24C@amazon.com>
On 2021-Sep-17, Bossart, Nathan wrote:
> > That was the first implementation, a few versions of the patch ago. An
> > added benefit of a separate WAL record is that you can carry additional
> > data for validation, such as -- as suggested by Andres -- the CRC of the
> > partial data contained in the message that we're skipping. I didn't
> > implement that, but it should be trivial to add it.
>
> I see. IMO feels a bit counterintuitive to validate a partial record
> that you are ignoring anyway, but I suppose it's still valuable to
> know when the WAL is badly broken. It's not expensive, and it doesn't
> add a ton of complexity, either.
Yeah, we don't have any WAL record history validation other than the
verifying the LSN of the previous record; I suppose in this particular
case you could argue that we shouldn't bother with any validation
either. But it seems safer to do it. It doesn't hurt anything anyway.
--
Álvaro Herrera Valdivia, Chile — https://www.EnterpriseDB.com/
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To: pgsql-hackers@postgresql.org
Cc: alvherre@alvh.no-ip.org, bossartn@amazon.com, horikyota.ntt@gmail.com, andres@anarazel.de, masao.fujii@oss.nttdata.com, pgsql-hackers@lists.postgresql.org, mengjuan.cmj@alibaba-inc.com, Jakub.Wartak@tomtom.com
Subject: Re: prevent immature WAL streaming
In-Reply-To: <202109172122.y3kcil5qhfpy@alvherre.pgsql>
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