Re: A better SQL implementation?

From: David Cressey <>
Date: Thu, 08 Jun 2006 18:13:49 GMT
Message-ID: <xNZhg.6141$LN1.2852_at_trndny01>

"paul c" <> wrote in message news:v8Hhg.253654$7a.51847_at_pd7tw1no...
> David Portas wrote:
> > Cimode wrote:
> >> ...
> >>
> >>
> >
> > The paper is rather confusing to me. It claims the index structure is
> > the novel feature of Atlas but the author doesn't explain what the
> > index structure is or how it differs from other indexes. The only clue
> > is the diagram of "Normal" vs "Set" indexes but those terms and the
> > diagrams are strange to me and they explain nothing. How does this
> > system compare to bitmap indexes? Hashing? B-trees? Clustering? etc.
> > ...


> The first thing I noticed is the mistaken claim that various dbms's
> aren't capable of using more than one index in a single query. Maybe
> his references are twenty years old, I dunno.
> p


I'm glad you pointed this out. I noticed the same thing, but I figured I had to be misreading the paper.

If I go back twenty years, I was dealing with Rdb/VMS. Rdb/VMS was most certainly capable of using more than one index to resolve a single query. I can't believe that someone who worked on the original system-R would fail to know both Rdb/VMS and, more importantly, the algorithms the strategy generator uses to propose alternatives.

The way I figure it, my knowledge of Rdb/VMS is ten years out of date, and later implementations have probably moved forward from there. But maybe it's just another case of the industry forgetting its own history. We get to watch it be rediscovered. Wheee! Received on Thu Jun 08 2006 - 20:13:49 CEST

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