Re: Index Skip Scan

On Thu, Jul 04, 2019 at 10:06:11AM +1200, David Rowley wrote:
> On Thu, 4 Jul 2019 at 09:02, James Coleman <jtc331@gmail.com> wrote:
> > I think that example is the opposite direction of what David (Rowley)
> > is saying. Unique on {a, b} implies unique on {a, b, c} while you're
> > correct that the inverse doesn't hold.
> >
> > Unique on {a, b} also implies unique on {b, a} as well as on {b, a, c}
> > and {c, a, b} and {c, b, a} and {a, c, b}, which is what makes this
> > different from pathkeys.
> 
> Yeah, exactly. A superset of the unique columns is still unique.

Thanks for clarifying!

Best,
David.
-- 
David Fetter <david(at)fetter(dot)org> http://fetter.org/
Phone: +1 415 235 3778

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