> I suspect the tuple at (0,1) has been the subject of a failed update.
> Your problem here is that you're mistaking the t_ctid field of a tuple
> header for the tuple's address. It is not that; it's really just garbage
> normally, and is only useful to link forward to the next version of the
> row from an outdated tuple. I think we do initialize it to the tuple's
> own address during an INSERT, but either a completed or failed UPDATE
> would change it.
Thanks. That helps clarify the comments in htup_details.h, actually.
> I do not think there is any way to get the true address of a heap tuple
> out of a composite Datum manufactured from the tuple. Most of the other
> system columns can't be gotten from a composite Datum either, because of
> the field overlay in HeapTupleHeaderData's union t_choice.
Well shoot. That kinda spoils my plans.
What about this? Is the tuple currently being evaluated (I suppose in the
case of a sequential scan) available in the context of a function call?
Thanks again for your time! It's much appreciated.