"Donald Fraser" <demolish(at)cwgsy(dot)net> writes:
> My analysis at the time was that to access random records, performance
> deteriorated the further away the records that you were accessing were
> from the beginning of the index. For example using a query that had
> say OFFSET 250000 would cause large delays.
Well, yeah. OFFSET implies generating and discarding that number of
records. AFAICS there isn't any shortcut for this, even in a query
that's just an indexscan, since the index alone can't tell us whether
any given record would actually be returned.
regards, tom lane