Re: Trying to break online checksums with LLMs

On Mon, Sep 14, 2026 at 9:47 AM Daniel Gustafsson <daniel(at)yesql(dot)se> wrote:
> Thinking about this over the weekend I think there is really only one possible
> option. When enabling checksums online the data checksums launcher will have
> to scan the datadir for orphan files, and abort processing if any are found
> (and log which files it found). While we don't have a tool for clearning, I
> don't think online checksums can, or should, handle the orphan files in any way
> other than bailing out. This needs adding net new code, which this really
> isn't a great time to be doing. CC:ing Heikki from RMT since I know he has
> eyes on this already.

It's for the RMT to decide whether that's good enough, but I'm
skeptical. I think a big part of the problem here is that it's really
hard to make something race-free. But even if we solve that problem or
disclaim it, I feel like it doesn't leave users in a very good place.
A lot of users will experience failures and will have no easy way to
find their way out from under the problem. Against that, there's a
plausible argument that users want this feature enough that they'll
still be happier to have the feature despite that problem. My
counter-argument to that is that if we shipped features with usability
restrictions that severe in every release, I don't think we'd be where
we are today as a project. Limitations are fine, but limitations where
there's not much you can do to avoid the problem or recover from it
are pretty bad, IMHO.

--
Robert Haas