Re: corruption of WAL page header is never reported

From: Ranier Vilela <ranier(dot)vf(at)gmail(dot)com>
To: Yugo NAGATA <nagata(at)sraoss(dot)co(dot)jp>
Cc: Pg Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: corruption of WAL page header is never reported
Date: 2021-07-17 21:40:02
Message-ID: CAEudQArCvk=0ukdabGn038XjxhSrTDW794f8_QXCA-Qxd_dmrA@mail.gmail.com
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-hackers

Em sáb., 17 de jul. de 2021 às 16:57, Yugo NAGATA <nagata(at)sraoss(dot)co(dot)jp>
escreveu:

> Hello,
>
> I found that any corruption of WAL page header found during recovery is
> never
> reported in log messages. If wal page header is broken, it is detected in
> XLogReaderValidatePageHeader called from XLogPageRead, but the error
> messages
> are always reset and never reported.
>
> if (!XLogReaderValidatePageHeader(xlogreader, targetPagePtr,
> readBuf))
> {
> /* reset any error XLogReaderValidatePageHeader() might
> have set */
> xlogreader->errormsg_buf[0] = '\0';
> goto next_record_is_invalid;
> }
>
> Since the commit 06687198018, we call XLogReaderValidatePageHeader here so
> that
> we can check a page header and retry immediately if it's invalid, but the
> error
> message is reset immediately and not reported. I guess the reason why the
> error
> message is reset is because we might get the right WAL after some retries.
> However, I think it is better to report the error for each check in order
> to let
> users know the actual issues founded in the WAL.
>
> I attached a patch to fix it in this way.
>
I think to keep the same behavior as before, is necessary always run:

/* reset any error XLogReaderValidatePageHeader() might have set */
xlogreader->errormsg_buf[0] = '\0';

not?

regards,
Ranier Vilela

Attachment Content-Type Size
v1_report_corrupt_page_header.patch text/x-patch 687 bytes

In response to

Responses

Browse pgsql-hackers by date

  From Date Subject
Next Message Tomas Vondra 2021-07-17 22:46:09 Re: slab allocator performance issues
Previous Message Andres Freund 2021-07-17 21:14:05 Re: slab allocator performance issues