[postgis-devel] Try before you Buy

[Obe, Regina]

Paul,

I hope we are not creating yet another aggregate function here, but I
assume you are just doing this so we can test and compare.

st_geometryarray(the_geom)

Isn't this what ST_Accum is supposed to do in which case for the final
version,  shouldn't you just replace the existing functionality of
ST_Accum rather than introducing yet another term in my already limited
brain cells?

Thanks,
Regina 

-----Original Message-----
From: postgis-devel-bounces at postgis.refractions.net
[mailto:postgis-devel-bounces at postgis.refractions.net] On Behalf Of Paul
Ramsey
Sent: Thursday, January 22, 2009 12:02 AM
To: PostGIS Development Discussion
Subject: [postgis-devel] Try before you Buy

All the pieces of the new super-fast cascaded geometry are now in SVN.
You'll need an absolutely fresh copy of GEOS to use them, but once you
do, you can run something like this:

aggtest=# select
geometrytype(_unite_garray_fast(st_geometryarray(the_geom))) from
sample_poly;
       geometrytype --------------
 MULTIPOLYGON
(1 row)
Time: 23267.905 ms


note that
 st_union() is still bound against the oldest implementation
 st_union_fast() is bound against an implementation with slow
aggregation but fast GEOS union
 _unite_garray_fast(st_geometryarray()) is the only way to get the
ultimate speed right now

Unfortunately, it looks I'm going to need a special finalfunc for
every single aggregate that takes in the internal pointer to the
side-cache. That makes all the aggregates less pretty, since they
won't use function(geometry[]) as their finalfunc anymore. The
cleanest way would be to have those finalfuncs do little more than
call other functions.

Mark, is there a prescribed way to call postgresql functions (ones
with (PG_FUNCTION_ARGS) as the argument) from other internal
functions?

Paul
_______________________________________________
postgis-devel mailing list
postgis-devel at postgis.refractions.net
http://postgis.refractions.net/mailman/listinfo/postgis-devel
-----------------------------------------
The substance of this message, including any attachments, may be
confidential, legally privileged and/or exempt from disclosure
pursuant to Massachusetts law. It is intended
solely for the addressee. If you received this in error, please
contact the sender and delete the material from any computer.