From: Tom Lane <tgl@sss.pgh.pa.us>
To: Alvaro Herrera <alvherre@alvh.no-ip.org>
cc: Amul Sul <sulamul@gmail.com>, Andres Freund <andres@anarazel.de>,
        Andrew Dunstan <andrew@dunslane.net>,
        "Bossart,
    Nathan" <bossartn@amazon.com>,
        Kyotaro Horiguchi <horikyota.ntt@gmail.com>,
        "masao.fujii@oss.nttdata.com" <masao.fujii@oss.nttdata.com>,
        "pgsql-hackers@lists.postgresql.org"
 <pgsql-hackers@lists.postgresql.org>,
        "mengjuan.cmj@alibaba-inc.com" <mengjuan.cmj@alibaba-inc.com>,
        "Jakub.Wartak@tomtom.com" <Jakub.Wartak@tomtom.com>,
        Ryo Matsumura <matsumura.ryo@fujitsu.com>
Subject: Re: prevent immature WAL streaming
In-reply-to: <202111251915.zme6752ri4w3@alvherre.pgsql>
References: <202111251915.zme6752ri4w3@alvherre.pgsql>
Comments: In-reply-to Alvaro Herrera <alvherre@alvh.no-ip.org>
	message dated "Thu, 25 Nov 2021 16:15:48 -0300"
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Date: Thu, 25 Nov 2021 14:18:20 -0500
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Alvaro Herrera <alvherre@alvh.no-ip.org> writes:
> On 2021-Nov-25, Tom Lane wrote:
>> Uh, why?  The fix should remove the problem, and if it doesn't, we're
>> still looking at inconsistent WAL aren't we?

> The problem is that the bug occurs while writing the WAL record.  Fixed
> servers won't produce such records, but if you run an unpatched server
> and it happens to write one, without a mitigation you cannot get away
> from FATAL during replay.

Really?  AFAICS the WAL record contains the correct value, or at least
we should define that one as being correct, for precisely this reason.

			regards, tom lane