[postgis-users] problem with st_collect()

[Kevin Neufeld]

Be careful with ST_Collect.   As the name implies, it will collect all the geometries in the set into a single geometry 
object.   If your table is gigabytes in size, running over the whole table will create a single geometry collection that 
is gigabytes in size ... which in all likelihood is really rather useless in any GIS application and will probably 
overwhelm your postgresql instance.

ST_Collects is definitely useful, but just be sure you really want a single (potentially very large and clumsy) geometry 
object.

-- Kevin

Marc-André Trottier wrote:
> hi!
> i have a problem with this request :
> select st_collect(geometryN(setsrid(the_geom, 32198),1)) from 'table_name';
> 
> this will return no results if "the_geom" contain  too much rows or 
> "the_geom" are too complex. 
> 
> How can i solve this problem ?
> 
> thanks
> 
> Marc-andré
>  
> 
> 
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