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From: Jose (jmalv04_at_[hidden])
Date: 2005-10-20 18:50:56

RML an order of magnitude faster

RTL: 11 sec and 330 ms
RML: 340 ms and 50 ms

RML output attached

On 10/21/05, Arkadiy Vertleyb <vertleyb_at_[hidden]> wrote:
> "Calum Grant" <calum_at_[hidden]> wrote
> > I frankly have no idea how I would implement that problem in SQL, but
> > then this was a problem you chose to be very difficult to solve using a
> > SQL notation.
> I am not an SQL expert, but should be something like this (if I remember
> correctly):
> SELECT number, name, city, COUNT(*) AS cnt
> FROM mytable a, mytable b
> WHERE [the long condition based on coordinates]
> GROUP BY a.number
> Then you hope that the optimizer figures out how to not compare every
> possible pair ;-)
> This exact statement I modeled in RTL, but RTL also specifies HOW to do
> things in addition to WHAT to do, so I was able to do a smartrer
> (range-based) query.
> I am thrilled with your performance results, though (although I consider
> them the results of a by-hand solution). Did you completely avoid
> calculating the distance? If so, I think any such solution would provide
> only approximate result (although it might happen to be a pretty good
> approximation).
> Regards,
> Arkadiy
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