> >
> > As far as i can see, postgresql select a simple "INDEX SCAN using index"
> > on table.
>
> That's because the index does not hold all the information. So INDEX
> ONLY is impossible.
>
Thank you for your quick answer, but there is something a don't
understand:
the index holds all attributes' values (one index entry/one table entry).
Right?
given a query with only this attribute on SELECT clause, which is the
missing information, that do not exist in index?