Re: pg_waldump: support decoding of WAL inside tarfile

Hi,

On 2026-04-01 06:39:05 -0400, Andrew Dunstan wrote:
>
> On 2026-03-31 Tu 10:05 PM, Thomas Munro wrote:
> > On Mon, Mar 30, 2026 at 11:23 AM Tom Lane<tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> > > Thomas Munro<thomas(dot)munro(at)gmail(dot)com> writes:
> > > > Anyway, given the defaults, GNU tar + ZFS/BTRFS users must be pretty
> > > > unlikely to hit this in the wild, and the symptom is a confusing error
> > > > in a maintenance tool, not corruption, so I don't think this is a big
> > > > deal. I might still try teaching the astreamer code to understand PAX
> > > > 1.0 when it sees it in the next cycle though, for the benefit of
> > > > FreeBSD users.
> > > I agree that this isn't too critical if the effects are confined to
> > > pg_waldump. I believe that pg_basebackup and pg_verifybackup also use
> > > astreamer_tar.c, but it's not clear to me if they'd ever be asked to
> > > parse files made by tar(1) and not by our own sparseness-ignorant
> > > tar-writing code. If they can be, that'd be a higher-priority reason
> > > to fill in this gap.
> > I pushed the workaround for the test.
>
>
> It occurred to me this morning that we probably shouldn't run this test on
> Windows, and if we do we shouldn't be using /dev/null (the Windows
> equivalent of which is just "nul"). The simplest fix would just be to add a
> "!$windows_os" to the if test.

Why should we skip this test on windows?

I think we have historically been way too liberal about sprinkling
!$windows_os test disablements around. More than once there were actual bugs
that we just swept under the rug by disabling the tests that detected them.
Either we support windows or we don't.

Greetings,

Andres Freund