[postgis-devel] RectDistance

[Daniel Baston]

Hi Paul,

Do you plan to keep this function present but "hidden" for 2.5 ?

Dan

On Thu, Feb 22, 2018 at 2:50 PM Paul Ramsey <pramsey at cleverelephant.ca>
wrote:

> Oh, I neglected to mention: some performance queries and results
> catalogued here, using my favourite BC political boundaries data (poly
> vs poly).
>
> https://gist.github.com/pramsey/9638940582bd45d74c7d0fb1d47f6083
>
> I suppose some tests with points/lines in particular would help to
> confirm cut-off points for complexity.
>
> P
>
>
> On Thu, Feb 22, 2018 at 11:46 AM, Paul Ramsey <pramsey at cleverelephant.ca>
> wrote:
> > I have now added a _ST_DistanceRectTreeCached(geom, geom) that does
> > caching, so for cases with nested loop joins we should see improved
> > performance. There's still cases (small geom vs small geom) that are
> > handled better with the existing code. And I recall that Nik found
> > some large cases that are degenerate too?
> > Anyways, it seems like the final implementation of Distance() will end
> > up being a hodgepodge with some magic number rules in the middle
> > determining which code line to use.
> > P
> >
> >
> > On Tue, Feb 20, 2018 at 1:53 PM, Paul Ramsey <pramsey at cleverelephant.ca>
> wrote:
> >> OK, it's in there, for those who want to try it out,
> >> _ST_DistanceRectTree(g1 geometry, g2 geometry)
> >> There is no caching in this version, so it's building and tossing away
> >> the trees at every invocation.
> >> P.
> >>
> >> On Tue, Feb 20, 2018 at 1:49 PM, Bborie Park <dustymugs at gmail.com>
> wrote:
> >>> +1
> >>>
> >>> On Tue, Feb 20, 2018 at 12:14 PM, Regina Obe <lr at pcorp.us> wrote:
> >>>>
> >>>> No objections from me.  +1 to just bring it in 2.5.
> >>>>
> >>>> I'm too lazy to test another branch, but if in place, I'd be willing
> to
> >>>> test it out.
> >>>>
> >>>> Thanks,
> >>>> Regina
> >>>>
> >>>> -----Original Message-----
> >>>> From: postgis-devel [mailto:postgis-devel-bounces at lists.osgeo.org] On
> >>>> Behalf Of Paul Ramsey
> >>>> Sent: Tuesday, February 20, 2018 2:26 PM
> >>>> To: PostGIS Development Discussion <postgis-devel at lists.osgeo.org>
> >>>> Subject: [postgis-devel] RectDistance
> >>>>
> >>>> Hey all,
> >>>>   I've had a branch running for a while, that Nik has tested a
> little, for
> >>>> tree-based distance calculations. I've been doing some testing on it
> and
> >>>> finding that when it's good, it's very very good (10x improvements
> when
> >>>> dealing with large geometries) and when it's bad, it's not so great
> (3x
> >>>> worse than existing naive distance on small-vs-small geometries).
> >>>>   All this so far without also reaching into the next obvious
> enhancement,
> >>>> adding a caching behaviour, like the point-in-polygon/geos code. That
> will
> >>>> make everything about 2x faster yet, as about 50% of the time seems
> to be
> >>>> spent in building up trees.
> >>>>   I'd like to merge my branch in, along with a temporary testing
> function
> >>>> _ST_DistanceRectTree(geom, geom) so that we can figure out how we
> exactly
> >>>> want to put this code to use. Any objections? If nothing else, it will
> >>>> replace the current dead code lying in lwtree.c.
> >>>>
> >>>> P.
> >>>> _______________________________________________
> >>>> postgis-devel mailing list
> >>>> postgis-devel at lists.osgeo.org
> >>>> https://lists.osgeo.org/mailman/listinfo/postgis-devel
> >>>>
> >>>> _______________________________________________
> >>>> postgis-devel mailing list
> >>>> postgis-devel at lists.osgeo.org
> >>>> https://lists.osgeo.org/mailman/listinfo/postgis-devel
> >>>
> >>>
> >>>
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