Simon Riggs wrote:
On Sun, 2005-12-18 at 15:02 +1300, Mark Kirkwood wrote:
Yeah - the quoted method of "make a cartesian product of the dimensions
and then join to the fact all at once" is not actually used (as written)
in many implementations
But it is used in some, which is why I mentioned it.
I gave two implementations, that is just (1)
Sorry Simon, didn't mean to imply you shouldn't have mentioned it - was
merely opining about its effectiveness....
- probably for the reasons you are pointing out.
I found these two papers whilst browsing:
http://www.cs.brown.edu/courses/cs227/Papers/Indexing/O'NeilGraefe.pdf
http://www.dama.upc.edu/downloads/jaguilar-2005-4.pdf
They seem to be describing a more subtle method making use of join
indexes and bitmapped indexes.
Which is the option (2) I described.
Ok - I misunderstood you on this one, and thought you were describing
the "star transformation" - upon re-reading, I see that yes, it's more
or less a description of the O'Neil Graefe method.
best wishes
Mark
