[Tilecache] Tilecache 2.0.1 Segfault

[Christopher Schmidt]

On Mon, Mar 17, 2008 at 03:58:44PM -0500, Steve Lime wrote:
> Hi all: I'm using tilecache with a MapServer layer and running into problems when seeding the cache. In this instance
> all the layers in the mapfile are STATUS DEFAULT, on all the time. Running the seeding program seems to work ok
> with 2 exceptions:
> 
>   1) for every tile I get a WMS exception
> 
>   <CTYPE ServiceExceptionReport SYSTEM "http://schemas.opengis.net/wms/1.1.1/exception_1_1_1.dtd">
>     <ServiceExceptionReport version="1.1.1">
>       <ServiceException code="LayerNotDefined">
>         msWMSLoadGetMapParams(): WMS server error. Invalid layer(s) given in the LAYERS parameter.
>       </ServiceException>
>   </ServiceExceptionReport>
> 
> This is expected I guess since there is no layer specified in the tilcache.cfg file (since all are on by default). The
> tiles ARE created despite the error message. Would be nice to suppress that if it's benign.

Since TileCache uses the owsParams way of loading a mapobj, it has the
same requirements that a WMS Request does, so this is 'automatic': I'm
not sure how you're getting a WMS Exception but still getting tiles
created? That definitely seems weird to me.

>   2) after every 500 to 1,000 tiles or I get a segmentation fault. No other error information
> 
> If I re-run the seed command it picks up again from where it dies, although I sometimes have to run it twice to clear
> our any file locks. It'll run another 500 to 1,000 or so and it dies again.
> 
> Could be a MapServer issue or TileCache, not sure. The debugger gives me:
> 
>   Program received signal SIGSEGV, Segmentation fault.
>   [Switching to Thread 1075357376 (LWP 31768)]
>   0x400d8f4c in mempcpy () from /lib/tls/libc.so.6
> 
> Has anyone else into anything like this?

I've seen this on a SuSE box as well. (Specifically, 'hypersphere', a
telasciecne/OSGeo machine.) As far as I know, this is a MapServer
segfault of some kind: does a backtrace help you here? I've never had
the desire to debug it, to be honest. I've never had it happen on
Debian.  

Regards,
-- 
Christopher Schmidt
MetaCarta