Re: Enable data checksums by default

Hi,

On 2019-03-22 12:07:22 -0400, Tom Lane wrote:
> Christoph Berg <myon(at)debian(dot)org> writes:
> > I think, the next step in that direction would be to enable data
> > checksums by default. They make sense in most setups,
>
> Well, that is exactly the point that needs some proof, not just
> an unfounded assertion.
>
> IMO, the main value of checksums is that they allow the Postgres
> project to deflect blame. That's nice for us but I'm not sure
> that it's a benefit for users. I've seen little if any data to
> suggest that checksums actually catch enough problems to justify
> the extra CPU costs and the risk of false positives.

IDK, being able to verify in some form that backups aren't corrupted on
an IO level is mighty nice. That often does allow to detect the issue
while one still has older backups around.

My problem is more that I'm not confident the checks are mature
enough. The basebackup checks are atm not able to detect random data,
and neither basebackup nor backend checks detect zeroed out files/file
ranges.

Greetings,

Andres Freund