Re: [UNVERIFIED SENDER] Re: pg_upgrade can result in early wraparound on databases with high transaction load

On 2022-07-05 Tu 12:59, Tom Lane wrote:
> Bruce Momjian <bruce(at)momjian(dot)us> writes:
>> This patch has been applied back to 9.6 and will appear in the next
>> minor release.
> I have just discovered that this patch broke pg_upgrade's ability
> to upgrade from 8.4:
>
> $ pg_upgrade -b ~/version84/bin -d ...
> Performing Consistency Checks
> -----------------------------
> Checking cluster versions ok
> The source cluster lacks some required control information:
> latest checkpoint oldestXID
>
> Cannot continue without required control information, terminating
> Failure, exiting
>
> Sure enough, 8.4's pg_controldata doesn't print anything about
> oldestXID, because that info wasn't there then.
>
> Given the lack of field complaints, it's probably not worth trying
> to do anything to restore that capability. But we really ought to
> update pg_upgrade's code and docs in pre-v15 branches to say that
> the minimum supported source version is 9.0.

So it's taken us a year to discover the issue :-( Perhaps if we're going
to say we support upgrades back to 9.0 we should have some testing to be
assured we don't break it without knowing like this. I'll see if I can
coax crake to do that - it already tests back to 9.2.

cheers

andrew

--
Andrew Dunstan
EDB: https://www.enterprisedb.com