[mapserver-users] VRT memory usage (from C# Mapscript)

[Frank Warmerdam]

Lisa Gaudette wrote:
> I have an application using C# Mapscript where I've got a large number of
> .png tiles that wind up representing the same area but under different
> conditions. In order to avoid having huge numbers of duplicate .wld files,
> I'm using .vrt files to index the tiles.
> 
> However, I've realized that each time a request is made for a different map,
> my memory usage increases. I can duplicate that with the following code,
> where the mapfiles contain .vrt layers but it's fine with a .shp tileindex.
> This happens even when the 2nd map represents a much smaller area with many
> fewer tiles than the first.

Lisa,

In recent versions of MapServer an effort is made to keep GDAL files open
between render requests for raster layers with a single file as opposed
to a tile index.  I wonder if you might be running into a problem with
this behavior in a long running mapscript script.  I don't understand
the whole context in which you are operating so I could be off base.  But
you might consider adding:

   PROCESSING "CLOSE_CONNECTION=NORMAL"

to your raster layer to force the files to be closed at the end of a render.

Best regards,
-- 
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
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and watch the world go round - Rush    | Geospatial Programmer for Rent