Date: Thu, 20 Jan 2022 19:30:42 -0800
From: Noah Misch <noah@leadboat.com>
To: Thomas Munro <thomas.munro@gmail.com>
Cc: pgbf@twiska.com, Tom Lane <tgl@sss.pgh.pa.us>,
	Michael Paquier <michael@paquier.xyz>,
	pgsql-hackers <pgsql-hackers@postgresql.org>
Subject: Re: XLogReadRecord() error in XlogReadTwoPhaseData()
Message-ID: <20220121033042.GA903845@rfd.leadboat.com>
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On Fri, Jan 21, 2022 at 08:34:22AM +1300, Thomas Munro wrote:
> On Mon, Jan 17, 2022 at 10:02 AM Noah Misch <noah@leadboat.com> wrote:
> > - Report a Debian bug for the sparc64+ext4 zeros problem.
> 
> I suspect that 027_stream_regress.pl hits this kernel bug with high
> probability[1].  I wonder if the owner of kittiwake and tadarida would
> consider setting up an xfs file system?  Or alternatively, since ext4
> didn't support concurrent writes until recently, I wonder if there is
> an option somewhere to turn the new concurrency stuff off, or failing
> that, if we could temporarily downgrade the kernel to an older version
> that does inode-level read/write locking.

If the write-only-new-bytes approach works, I think we'd want to revert those
changes.  Perhaps a cheaper stopgap is to make the affected tests skip on
sparc Linux.  Is that worth doing?  (Could even limit the skip to ext4,
e.g. by testing "df -x ext4 . >/dev/null".)

> [1] https://www.postgresql.org/message-id/CA%2BhUKG%2BeuZ%3Ddc27ZB%3Ds74x0q%3DzU%3D2%3Dvs8%2B6TkJoTUiCPUd2dQA%40mail.gmail.com