Re: pg15b2: large objects lost on upgrade

On 8/2/22 3:39 PM, Tom Lane wrote:
> "Jonathan S. Katz" <jkatz(at)postgresql(dot)org> writes:
>> On 8/2/22 3:23 PM, Robert Haas wrote:
>>> I'm not quite sure how to rule that theory in or out, though.
>
>> Without overcomplicating this, are we able to check to see if autovacuum
>> ran during the course of the test?
>
> Looks like we're all thinking along the same lines.
>
> While not smoking guns, these definitely prove that autovac was active.

> If that is the explanation, then it leaves us with few good options.
> I am not in favor of disabling autovacuum in the test: ordinary
> users are not going to do that while pg_upgrade'ing, so it'd make
> the test less representative of real-world usage, which seems like
> a bad idea. We could either drop this particular check again, or
> weaken it to allow new relfrozenxid >= old relfrozenxid, likewise
> relminxid.

The test does look helpful and it would catch regressions. Loosely
quoting Robert on a different point upthread, we don't want to turn off
the alarm just because it's spuriously going off.

I think the weakened check is OK (and possibly mimics the real-world
where autovacuum runs), unless you see a major drawback to it?

Jonathan