Re: pg_upgrade: Support for upgrading to checksums enabled

On Thu, Apr 3, 2025 at 3:25 AM Peter Eisentraut <peter(at)eisentraut(dot)org> wrote:
>
> On 11.03.25 11:42, Peter Eisentraut wrote:
> > Here is an updated patch that works more along those lines. It adds a
> > pg_upgrade option --update-checksums, which activates the code to
> > rewrite the checksums. You must specify this option if the source and
> > target clusters have different checksum settings.
> >
> > Note that this also works to hypothetically upgrade between future
> > different checksum versions (hence "--update-*", not "--enable-*").
> > Also, as the patch is currently written, it is also required to specify
> > this option to downgrade from checksums to no-checksums. (It will then
> > write a zero into the checksum place, as it would look if you had never
> > used checksums.) Also, you can optionally specify this option even if
> > the checksum settings are the same, then it will recalculate the
> > checksums. Probably not all of this is useful, but perhaps a subset of
> > it. Thoughts?
> >
> > Also, I still don't know what to do about the Windows code path in
> > copyFile(). We could just not support this feature on Windows? Or
> > maybe the notionally correct thing to do would be to move that code into
> > copyFileByRange(). But then we'd need a different default on Windows
> > and it would require more documentation. I don't know what to do here
> > and I don't have enough context to make a suggestion. But if we don't
> > answer this, I don't think we can move ahead with this feature.
>
> I'm not sensing much enthusiasm for this feature or for working out the
> remaining problems, so I'm closing this commitfest entry.
>

That's unfortunate; I think there is enthusiasm for the feature, just
not enough to overcome the questions around Windows support.

Robert Treat
https://xzilla.net