Re: basebackup: do not verify checksums on pages written before enabling checksums

From: Bertrand Drouvot <bertranddrouvot(dot)pg(at)gmail(dot)com>
To: Zsolt Parragi <zsolt(dot)parragi(at)percona(dot)com>
Cc: Daniel Gustafsson <daniel(at)yesql(dot)se>, pgsql-hackers(at)lists(dot)postgresql(dot)org, Yilin Zhang <jiezhilove(at)126(dot)com>
Subject: Re: basebackup: do not verify checksums on pages written before enabling checksums
Date: 2026-08-17 13:02:12
Message-ID: aoMGVEx9unsGenBV@bdtpg
Views: Whole Thread | Raw Message | Download mbox | Resend email
Thread:
Lists: pgsql-hackers

Hi,

On Mon, Aug 17, 2026 at 03:36:03AM -0700, Zsolt Parragi wrote:
> > > but 010_backup_straddle.pl does not. Should 010_backup_straddle.pl also disable
> > > bgwriter to preserve dirty pages?
> >
> > I'm not sure, does it need to?
>
> I think the test should be safe as-is, since we have more than enough
> shared buffers. Even with 32mb shared buffers, the test reliably
> errors out without the fix.

Couldn't the bgwriter still flush those dirty pages, regardless of the shared
buffers size? On a slower BF animal, the launcher may remain paused long enough
for additional bgwriter cycles to flush the pages. I'd still set
bgwriter_lru_maxpages = 0 to make the test more deterministic.

Regards,

--
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com

In response to

Browse pgsql-hackers by date

  From Date Subject
Next Message Peter Eisentraut 2026-08-17 13:03:12 Re: [PATCH] ternary reloption type
Previous Message Xuneng Zhou 2026-08-17 12:57:52 Re: Implement waiting for wal lsn replay: reloaded