Re: corruption of WAL page header is never reported

From: Fujii Masao <masao(dot)fujii(at)oss(dot)nttdata(dot)com>
To: Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org>, Kyotaro Horiguchi <horikyota(dot)ntt(at)gmail(dot)com>
Cc: nagata(at)sraoss(dot)co(dot)jp, ranier(dot)vf(at)gmail(dot)com, pgsql-hackers(at)postgresql(dot)org
Subject: Re: corruption of WAL page header is never reported
Date: 2021-09-10 01:38:39
Message-ID: a86d2f6f-0cca-57d8-a601-e44c5dd07edc@oss.nttdata.com
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On 2021/09/07 2:02, Fujii Masao wrote:
> Even if we do this while NOT in standby mode, ISTM that this function doesn't
> return with a valid errmsg_buf because it's reset. So probably the comment
> should be updated as follows?
>
> -------------------------
> We don't do this while not in standby mode because we don't need to retry
> immediately if the page header is not valid. Instead, XLogReadRecord() is
> responsible to check the page header.
> -------------------------

I updated the comment as above. Patch attached.

- * it's not valid. This may seem unnecessary, because XLogReadRecord()
+ * it's not valid. This may seem unnecessary, because ReadPageInternal()
* validates the page header anyway, and would propagate the failure up to

I also applied this change because ReadPageInternal() not XLogReadRecord()
calls XLogReaderValidatePageHeader().

Regards,

--
Fujii Masao
Advanced Computing Technology Center
Research and Development Headquarters
NTT DATA CORPORATION

Attachment Content-Type Size
v3-0001-Don-t-hide-xlog-page-header-errors-while-recovery.patch text/plain 1.7 KB

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