Hi Michael, Volker I have been thinking for a while about hacking a ub-tree for couch, http://en.wikipedia.org/wiki/UB-tree, but am concerned about the patent issues, http://archives.postgresql.org/pgsql-general/2002-04/msg00349.php, I know this was discussed a lot on the postgresql lists, wonder if anyone here knows any more about it?
Norman On Tue, Nov 9, 2010 at 2:28 AM, Volker Mische <[email protected]> wrote: > Hi Michael, > > On 11/09/2010 07:14 AM, Michael Zedeler wrote: >> Hi CouchDB-users (and developers). >> >> Thanks for a great product and very useful discussions on the mailing list. >> >> Does anyone know if there has been an effort into making >> multi-dimensional queries possible? >> >> Given a d-dimensional keyspace, I'd like to be able to get all elements >> in a d-dimensinal hypercube. It could be implemented using kd-trees. >> >> Any thoughts? >> >> Regards, >> >> Michael. >> > > You could use an kd-tree, though I'd prefer a multidimensional variation > of the r-tree. The reason is, that the kd-tree is space partitioning, > which means you need to know the range the keys are in upfront (or do > some tricks which will make it more like an r-tree). > > In an r-tree you partition the data, so your data structure grows as > data from outside the current maximum range comes in. > > I'd love to see a multidimensional index, but atm I'm still busy with my > 2-dimensional index. So if you'd like to hack on it and need any help, > let me know. > > Cheers, > Volker >
