Horton

Re: The XLogFindNextRecord() routine find incorrect record start point after a long continuation record

Fujii Masao <masao.fujii@gmail.com>

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From: Fujii Masao <masao.fujii@gmail.com>
To: Michael Paquier <michael@paquier.xyz>
Cc: Andrey Lepikhov <a.lepikhov@postgrespro.ru>, PostgreSQL mailing lists <pgsql-bugs@lists.postgresql.org>
Date: 2019-11-07T07:37:00Z
Lists: pgsql-bugs 
On Thu, Nov 7, 2019 at 12:41 PM Michael Paquier <michael@paquier.xyz> wrote:
>
> On Thu, Nov 07, 2019 at 02:41:29AM +0900, Fujii Masao wrote:
> > I created the problematic WAL file artificially by using
> > pg_logical_emit_message() and sucessfully reproduced
> > the error.
>
> Good idea.  I didn't know this one.
>
> > I attached the WAL file that I created. You can
> > reproduce the issue by
> >
> >     pg_waldump 000000010000000000000008 -s 0/08002028
>
> Assertion failure reproduced here.
>
> > The patch looks good to me. Barrying any objection, I will commit it.
> > XLogFindNextRecord() must return the valid record starting position,
> > but currently could return the starting position of WAL page
> > (not valid WAL record) in the case that you described. This is
> > the cause of the issue.
>
> No issues from here, thanks for taking care of it.

Thanks for the check! I committed the patch!

Regards,

-- 
Fujii Masao

Commits

  1. Fix assertion failure when running pgbench -s.

  2. Fix pg_xlogdump so that it handles cross-page XLP_FIRST_IS_CONTRECORD record.