[postgis-users] trying to debug segmentation violation

Mark Cave-Ayland m.cave-ayland at webbased.co.uk
Wed Sep 21 09:46:35 PDT 2005


> -----Original Message-----
> From: postgis-users-bounces at postgis.refractions.net 
> [mailto:postgis-users-bounces at postgis.refractions.net] On 
> Behalf Of Jessica M Salmon
> Sent: 21 September 2005 17:04
> To: postgis-users at postgis.refractions.net
> Subject: [postgis-users] trying to debug segmentation violation
> 
> 
> A plpsql function I wrote is starting to occasionally kick me 
> off with a signal 11 error code. It seems to occur while 
> calculating a 300m buffer around the transformed point 
> transform(geomfromewkt('SRID=4326;POINT(-118.335235595703
> 36.8628845214844)', 102008)  When I do this at the command 
> line (from the same geometry in memory as the function was 
> accessing), it gives a result just fine. The function 
> calculates thousands upon thousands of these just fine, but 
> objects to this one and one other.
> 
> I have two questions:
> 1) How can I obtain more information on where exactly the 
> segV is occurring? I know where it happens in my code, but 
> since it seems to happen in a geos function, I cannot use 
> print statements to get any more detail.
> 2) What are the common causes of this sort of error?
> 
> Thanks for any responses,
> Meghan


Hi Meghan,

Unfortunately an intermittent Signal 11 tends to indicate a hardware
problem, normally bad memory. If you are using an x86 processor, then it's
worth letting memtest86 (http://www.memtest86.com/) run overnight to see if
it finds any errors, and if so, replace the faulty module and see if the
problem still occurs.


Kind regards,

Mark.

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