Re: [HACKERS] pg_upgrade failed with error - ERROR: column "a" in child table must be marked NOT NULL

On Thu, Sep 28, 2023 at 01:29:21PM -0500, Justin Pryzby wrote:
> On Thu, Dec 14, 2017 at 07:18:59PM +0700, Ali Akbar wrote:
> > By the way, should i add this patch to the current commitfest?
> 
> The patch for pg_upgrade --check got forgotten 6 years ago, but it's a
> continuing problem (we hit it again which cost an hour during
> pg_upgrade) and ought to be (have been) backpatched.

You mean when upgrading from an instance of 9.6 or older as c30f177 is
not there, right?  With the new project policy to support pg_upgrade
for 10 years, there's still a very good argument for backpatching a
pre-check down to v11.

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.

> I didn't dig into it, but maybe it'd even be possible to fix the issue
> with ALTER..DROP NOT NULL ...

Interesting point.  I haven't checked either.

[1]: https://postgr.es/m/CACQjQLqoXTzCV4+-s1XOT62tY8ggkZkH4kY03gm2aQYOMXE+SA@mail.gmail.com
--
Michael