[Chameleon] raster hang

[Paul Spencer]

Ken-ichi,

this is a curious problem.  I am at a loss to understand why this might 
be a problem.  I have only one thought that came to mind, PHP can be 
configured to allow a maximum amount of memory per running process and I 
think the default is 8mb (the setting is in php.ini).

I don't know the internals of MapServer/GDAL memory management, but it 
may be possible that the PHP process is limiting memory and causing 
inefficient access to larger rasters.

There is probably another problem, but it would be interesting if you 
could modify your php.ini to increase the amount of memory available to 
php processes and report any differences in performance.

Cheers,

Paul

Ken-ichi wrote:

> Hi folks.  I've started trying to add a GeoTIFF to my Chameleon app, and 
> it really bogs it down, sometimes to a stand still.  The image I'm 
> experimenting with is a 29mb unsigned 8bit GeoTIFF created in Erdas.  
> The hangs are most frequent when the tiff occupies the whole map, and 
> when I say hang, I mean that the map just doesn't render.  The hangs 
> also seem to generate an httpd process that takes up a lot (>20%) of my 
> CPU activity.  The relevant portion of my map file is pretty simple:
> 
> LAYER
>    NAME "Test Raster"
>    TYPE RASTER
>    DATA "/path/to/data.tif"
>    STATUS DEFAULT
> END
> 
> I haven't specified an outputformat, except in the MAP section, where 
> I've set it to PNG (but I've switched around and that doesn't seem to 
> make much difference).  This problem does not seem to occur outside of 
> Chameleon (everything works fine in MapLab's ROSA applet), and it 
> doesn't happen every time the map is loaded  (although it inevitably 
> happens if you refresh the map enough).
> 
> Has anyone experienced this kind of behavior before?  Even better, 
> anyone have any recommendations?
> 
> -Ken-ichi
> 
> 
> _______________________________________________
> Chameleon mailing list
> Chameleon at lists.maptools.org
> http://lists.maptools.org/mailman/listinfo/chameleon
> 

-- 
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|Paul Spencer                           pspencer at dmsolutions.ca   |
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|Applications & Software Development                              |
|DM Solutions Group Inc                 http://www.dmsolutions.ca/|
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