Re: More Performance

> > We can't read data from the index.  It would be nice if we could, but we
> > can't.  I think we believe that there are very few cases where this
> > would be win.  Usually you need non-indexed data too.
> 
> I have used other databases where this _is_ possible in the past, and
> the win is big when the programmer codes for it.  Sure, most cases don't
> just use indexed data, but if the programmer knows that the database
> supports index-only scans then sometimes an extreme performance
> requirement can be met.
> 

Yes, totally true.  It is an extreme optimization.  In Ingres, you could
actually SELECT on the index and use that when needed.

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