Re: Multicolum index and primary key

On Mon, 2003-11-17 at 17:14, Peter Eisentraut wrote:
> 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.

Thank you. I have read the chapter but I wonder if the implicit index
created by the primary key behaves as a normal indexes at all.

ciao, Michele