On Fri, Sep 29, 2023 at 09:16:35AM +0900, Michael Paquier wrote: > You mean when upgrading from an instance of 9.6 or older as c30f177 is > not there, right?
No - while upgrading from v15 to v16. I'm not clear on how we upgraded *to* v15 without hitting the issue, nor how the "not null" got dropped... > Anyway, it seems like the patch from [1] has no need to run this check > when the old cluster's version is 10 or newer. And perhaps it should > mention that this check could be removed from pg_upgrade once v10 > support is out of scope, in the shape of a comment. You're still thinking of PRIMARY KEY as the only way to hit this, right? But Ali Akbar already pointed out how to reproduce the problem with DROP NOT NULL - which still applies to both v16 and v17.
