> > 2) Is it possible to write a where clause that can efficiently hit only
> > the tuples in the end of the table? If there is a way, then I could
> > test the idea without writing any code at all.
>
> Not sure, but you could try using the ctid column.
>
An alternative is to do a bulky ordered insert. Build an index on the table.
And write a where clause which just visit the big-value part of the table.
Regards,
Qingqing