[postgis-devel] GeomUnion speedups

[strk at refractions.net]

On Sat, Jun 25, 2005 at 12:19:09PM +0200, strk at refractions.net wrote:
...
> ------------------------------------------------------------------------
> 50 MultiPolygons test:
> ------------------------------------------------------------------------
> 
>         Classic geomunion, Martin JTS patches (geos-head)
>                 real    3m54.009s
>                 user    3m45.522s
>                 sys     0m1.489s
> 
>         Buffer(0) geomunion (geos-head)
>                 real    1m30.912s
>                 user    1m27.606s
>                 sys     0m0.555s
> 
> ------------------------------------------------------------------------

I tried the same tests linking postgis to libJTS,
Well, the "classic" version of it returns in about a minute
(faster then our Buffer(0) workaround), while buffer(0)
takes forever and eventually segfaults.

I wouldn't work on JTS for now, but it's interesting to see
that building 100 graphs and making 50 Union operations
with JTS takes less then building a *single* BIG graph and
making a *single* Buffer operation.

--strk;