Re: posgres 12 bug (partitioned table)

Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> On Thu, Jun 4, 2020 at 12:57 PM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> Pavel Biryukov <79166341370(at)yandex(dot)ru> writes:
>>> Hello. I'm catch error "virtual tuple table slot does not have system
>>> attributes" when inserting row into partitioned table with RETURNING
>>> xmin

> I wonder whether it's really correct to classify this as a bug. The
> subsequent discussion essentially boils down to this: the partitioned
> table's children could use any AM, and they might not all use the same
> AM. The system columns that are relevant for the heap may therefore be
> relevant to all, some, or none of the children. In fact, any fixed
> kind of tuple table slot we might choose to use for the parent has
> this problem. If all of the children are of the same type -- and today
> that would have to be heap -- then using that type of tuple table slot
> for the parent as well would make sense. But there's no real reason
> why that's the correct answer in general. If the children are all of
> some other type, using a heap slot for the parent is wrong; and if
> they're all of different types, it's unclear that anything other than
> a virtual slot makes any sense.

Well, if we want to allow such scenarios then we need to forbid queries
from accessing "system columns" of a partitioned table, much as we do for
views. Failing way down inside the executor seems quite unacceptable.

regards, tom lane