[postgis-devel] topology : new index on node table

[Rémi Cura]

The ticket :
http://trac.osgeo.org/postgis/ticket/2860

If fitting in memory, I would expect the 160k geom of the benchmark to be
imported in less than 30 sec in grass, cgal and geos.
300 sec for Postgis Topology batch mode would be a good goal (reachable and
nice achievement).

Cheers,
Rémi-C


2014-07-30 11:56 GMT+02:00 Rémi Cura <remi.cura at gmail.com>:

> Almost a 10x factor, really nice !
> Cheers,
> Rémi-C
>
>
> 2014-07-30 11:38 GMT+02:00 Sandro Santilli <strk at keybit.net>:
>
> On Wed, Jul 30, 2014 at 11:29:00AM +0200, Sandro Santilli wrote:
>>
>> > There's a reference dataset produced some time ago by a user who
>> resulted
>> > in a fix making topology creation much faster:
>> > http://lists.osgeo.org/pipermail/postgis-devel/2014-January/024078.html
>> >
>> > I still have a couple of diagrams showing population time before/after
>> > that are waiting for a blog post that I never find the time to write...
>>
>> Just a sneak preview of the blog post that might never be written
>>
>> Queries:
>>
>>  SELECT ST_CreateTopoGeo('million_poly_topo1', ST_Collect(geom))
>>  FROM ( SELECT geom from million_poly_topo1 order by gid limit 160000) as
>> f;
>>
>>  SELECT TopoGeo_addPolygon('million_poly_topo1', ST_GeometryN(geom,1))
>>  FROM ( SELECT geom from million_poly_topo1 order by gid limit 160000) as
>> f;
>>
>> Output topology has:
>>
>>  160167 nodes, 160167 edges, 160167 faces
>>
>> Times:
>>
>>  a: before starting
>>  b: Ensure face splitting algorithm uses the edge index (#2610)
>>  c: Drop all calls to geometry::text during topology population (#2616)
>>
>>       ST_CreateTopoGeo     TopoGeo_addPolygon
>>     +-------------------+--------------------+
>>  a  |    38352283.535   |    38375126.950    |
>>  b  |    12088554.776   |     9644736.277    |
>>  c  |    11963757.923   |     4984225.402    |
>>
>> I've a table with more numbers, with limits from 5000 to 160000.
>> The index change would make another configuration (d, I guess).
>>
>> Please please please file the ticket, maybe referencing this thread
>> and #2610 and #2616 as I'd really love to grow the optimizations further
>>
>> --strk;
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>>
>
>
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