Re: better page-level checksums

On Fri, Jun 10, 2022 at 6:16 AM Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
> > My preference is for an approach that builds on that, or at least
> > doesn't significantly complicate it. So a cryptographic hash or nonce
> > can go in the special area proper (structs like BTPageOpaqueData don't
> > need any changes), but at a page offset before the special area proper
> > -- not after.
> >
> > What disadvantages does that approach have, if any, from your point of view?
>
> I think it would be an extremely good idea to store the extended
> checksum at the same offset in every page. Right now, code that wants
> to compute checksums, or a tool like pg_checksums that wants to verify
> them, can find the checksum without needing to interpret any of the
> remaining page contents. Things get sticky if you have to interpret
> the page contents to locate the checksum that's going to tell you
> whether the page contents are messed up. Perhaps this could be worked
> around if you tried hard enough, but I don't see what we get out of
> it.

Is that the how block-level encryption feature from EDB Advanced Server does it?

--
Peter Geoghegan