[postgis-users] GEOS union() error
Kevin Neufeld
kneufeld at refractions.net
Tue Nov 6 14:49:32 PST 2007
Lee Keel wrote:
> Well that got me past that error, but now I have a much bigger problem. I
> need a way to speed up the geomunion process. I know I am asking a lot of
> this function, but I have about 40K rows and the process to do the geomunion
> has been running over 80 mins and still going. Does anyone have a better
> idea on how I can get the same results?
>
Just a thought here, but I don't think you need to use geomunion at
all. Try just collecting them together and then buffering your collection.
select buffer(collect(the_geom), 400) as the_geom from main;
Also, I don't know if this will help you since you're not really
performing any joins, but ...
Since you're attempting to do this all at once, if you have the memory,
I would make sure your work_mem is temporarily set as high as you can.
-- ie. this will temporarily set the amount of memory postgres can use
for the duration of your session to 1.2GB (the default is 1MB)
SET work_mem TO 1200000;
-------------
Kevin Neufeld
Software Developer
Refractions Research Inc.
300-1207 Douglas St.
Victoria, B.C., V8W 2E7
Phone: (250) 383-3022
Email: kneufeld at refractions.net
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