>From the benchmark, my understanding is that, on PostGIS 2.0: 1) for the 2D case, the best index is 'gist (columname)' 2) for the 3D case, the best index is 'gist (columname gist_geometry_ops_nd)' only when using specific 3D operators (ie: '&&&')
I think we should create the index for 2D case, just as we did on PostGIS 1.5. Re: the 3D case, 2) brings the question: should we add these new operators? Is it out of scope for the ticket? On Thursday, August 9, 2012 4:18:48 PM UTC-5, Flavio Curella wrote: > > I was running the wrong query for the 3D case. > I've updated the benchmark gist and added some test under PostGIS 1.5. > > On Thursday, August 9, 2012 4:03:45 PM UTC-5, Anssi Kääriäinen wrote: >> >> On 9 elo, 23:48, Jeremy Dunck <jdu...@gmail.com> wrote: >> > I'm fairly familiar with the django gis code, but I haven't been >> > following postgis 2.0. Could you point me towards some discussion of >> > the index changes from 1.5 to 2.0? On the face of it, I'm doubtful >> > that they've removed a useful form of indexing with no >> > replacement/alternative. >> > >> > It's hard for me to assess the patch w/o some more context re. the >> > upstream postgis changes. >> >> The only thing I have is this link in the ticket: >> http://blog.opengeo.org/2012/03/13/postgis-2-0-new-features-3d4d-indexing/ >> and then this link leads to this discussion: >> >> http://postgis.refractions.net/pipermail/postgis-devel/2010-December/011178.html >> >> >> My understanding of the issue: It seems one index type isn't available >> (at least not with the same name) in 2.0 compared to 1.5. This is the >> whole incompatibility problem from Django code perspective. The 2d >> index seems to be somewhat slower than the 1.5 version (at least as of >> December 2010). For this reason the whole index isn't created. >> >> So, there are actually two questions: >> - is there a better index for the 2d case >> - if not, shouldn't we still create the somewhat slower index, which >> could still be orders of magnitude faster than no index at all. >> >> - Anssi >> > -- You received this message because you are subscribed to the Google Groups "Django developers" group. To view this discussion on the web visit https://groups.google.com/d/msg/django-developers/-/82fMVVTUeTwJ. To post to this group, send email to django-developers@googlegroups.com. To unsubscribe from this group, send email to django-developers+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/django-developers?hl=en.
