On Tue, Apr 17, 2012 at 12:12 AM, Jeff Davis <pg...@j-davis.com> wrote:
> On Mon, 2012-04-16 at 16:22 +0400, Alexander Korotkov wrote: > > > There is a good overview article about spatial joins. > > http://www.cs.umd.edu/users/hjs/pubs/jacoxtods07.pdf > > Thank you, that's exactly the kind of overview I was looking for. > > > It shows that there is a lot of methods based on building temporaty > > indexes. It might mean that building of temporary GiST index is not a > > bad idea. > > That had occurred to me, but I was hesitant to only use temp indexes. It > still doesn't really offer a good solution when both sides of the join > are relatively large (because of random I/O). Also the build speed of > the index would be more important than it is now. > Note, that amount of random I/O during GiST index build significanlty dicreased after my GSoC project for buffering GiST index build. However, GiST index build is still quite CPU-expensive. This problem could be evaded by support of another methods of index build (another than producing a lot of penalty and picksplit calls). Hilbert curve and similar methods could help here. Implementation of such methods would require extension of GiST interface. ------ With best regards, Alexander Korotkov.
