Re: The documentation for storage type 'plain' actually allows single byte header

Andres Freund <andres@anarazel.de> writes:
> On 2023-01-15 18:08:21 -0500, Tom Lane wrote:
>> ri_newTupleSlot has the tupdesc we want, planSlot is a virtual slot
>> that has the bogus tupdesc, and for some reason heap_form_tuple is
>> getting called with planSlot's tupdesc not ri_newTupleSlot's.

> The way we copy a slot into a heap slot is to materialize the source slot and
> copy the heap tuple into target slot. Which is also what happened before the
> slot type abstraction (hence the problem also existing before that was
> introduced).

Hmm.  For the case of virtual->physical slot, that doesn't sound
terribly efficient.

> I think it's fairly fundamental that copying between two slots assumes a
> compatible tupdescs.

We could possibly make some effort to inject the desired attstorage
properties into the planSlot's tupdesc.  Not sure where would be a
good place.

            regards, tom lane