Re: pg_upgrade silently truncates nextMultiOffset to 32 bits

On 27/08/2026 20:25, Masahiko Sawada wrote:
> On Thu, Aug 27, 2026 at 1:58 AM Heikki Linnakangas <hlinnaka(at)iki(dot)fi> wrote:
>>
>> On 27/08/2026 11:20, Heikki Linnakangas wrote:
>>> On 27/08/2026 10:35, Masahiko Sawada wrote:
>>>> I considered using xid8 instead but it has only comparison operators
>>>> and no arithmetic, so we couldn't compute a delta between two
>>>> checkpoints.
>>>
>>> Hmm, that's a good point, although 'xid' didn't have those operators or
>>> arithmetic either.
>>
>> That was inaccurate: both 'xid' and 'xid8' do have comparison operators.
>> But they don't have a "minus" or "diff" operator, so you indeed cannot
>> easily do "b - a".
>>
>> I don't have a strong opinion, I'm happy with either bigint or xid8
>> here. Bigint is probably more convenient in practice, and it's good to
>> not confuse mxact offsets with transaction ids by abusing the xid8 type.
>> Then again, it was 'xid' before, which had the same issues and we went
>> with 'xid' anyway. Then again, now that it doesn't wrap around anymore,
>> maybe 'bigint' makes more sense now.
>
> I missed the point that we used to use 'xid' for that field. But I
> agree that 'bigint' makes more sense.
>
>> Would you like to decide and commit this, or would you prefer me to do it?
>
> I'm going to take them and go with the 'bigint' column if you're okay.
>
> I've added the commit messages to the patches.

Ok, thank you!

- Heikki