Re: Changing the state of data checksums in a running cluster

On 11/20/25 11:34 AM, Tomas Vondra wrote:
> On 11/19/25 22:03, Andreas Karlsson wrote:
>> Hi,
>>
>> I have been following these discussions but not read the patch in detail.
>>
>> This patch makes me worried especially with the new issues recently
>> uncovered. This was already a quite big patch and to fix these issues it
>> will likely have to become even bigger and given how this would become a
>> very rarely stressed code paths I wonder if we can actually ever become
>> confident that the patch works in all edge cases.
>>
>> Something like this need to be easy to understand for us to have any
>> hope at all to be comfortable in the correctness. Can we actually do that?
>>
>
> How's this different from any other complex patch? We get more familiar
> with the problem during review, identify issues, improve the patch to
> address them. And then again and again.

The difference I see is in how rarely anyone actually switches checksum
state in a production database, especially now that we enabled them by
default. A complex and rarely stressed code path is a minefield.

Andreas