"Greg Sabino Mullane" <greg@turnstep.com> writes:
>> Don't you miss for each subselect an order by tid ?
> No: since all the SELECTs are part of one statement, they
> will have the same (pseudo-random) implicit order.
Nope; Gaetano's right, you cannot assume that. It's entirely possible
for the planner to choose different plans depending on the OFFSET.
(Maybe not very likely, with such small offsets, but could happen.)
regards, tom lane