[postgis-users] GEOS union() error

[Lee Keel]

> -----Original Message-----
> From: postgis-users-bounces at postgis.refractions.net [mailto:postgis-users-
> bounces at postgis.refractions.net] On Behalf Of Obe, Regina
> Sent: Wednesday, November 07, 2007 9:01 AM
> To: PostGIS Users Discussion
> Subject: RE: [postgis-users] GEOS union() error
> 
> Well I've never seen that particular error before.  Usually if I need to
> bump up memsize, it explicitly says its "OUT OF MEMORY"
> 
> The specific error sounds like its trying to write to a non-existent
> address space or space already in use.  Not quite sure what would cause
> that.
> 
> Does it work if you limit your buffering to something like below?
> 
> SELECT buffer(collect(the_geom), 400) as the_geom
> FROM (SELECT the_geom from main limit 10) As newmain
> 
> Hope that helps,
> Regina
> 
[Lee Keel] 


Well this was an interesting test...  I tried 10 and it work.  I tried 100
and it worked.  Well I kept trying different things and it appears that
everything works up to limit of 444.  At 445, I get the "St9bad_alloc"
error.  I have confirmed that collect works with limits, but if I don't add
limit I get the following error:

ERROR: out of memory
SQL state: 53200
Detail: Failed on request of size 520184.

I have changed my work_mem to 1200MB and still got the error.

I have also done a count on the number of points and there are 1,244 points
for the first 444 geoms, and 1,246 for 445. (FYI, total number of points for
table is 104772.)  So there is no logical reason for number of points to be
causing the problem either.  Another test that I performed was to move the
collect outside of the buffer like:

select buffer(the_geom, 400) from (select collect(the_geom) as the_geom from
(select the_geom from main limit 445)foo2) foo

This resulted in the same "St9bad_alloc" error.  However, using 444 as limit
worked.

-LK


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