Michele Bendazzoli writes:
> ALTER TABLE public.table1
> ADD CONSTRAINT table1_pkey PRIMARY KEY(a, b, c);
>
> are the indexes over (a) and (a, b) redundant (and so useless)?
Exactly.
> p.s. I know, I'll have to begin to use the explain command ...
> I promise I'll do it ;-)
You could also have read the documentation about multicolumn indexes,
because it contains exactly this example.
--
Peter Eisentraut peter_e(at)gmx(dot)net