[mapserver-users] Version problems with overviews

[Jesse Cleary]

Hi folks

Apologies for the re-post.  This went out initially prior to our 
feedback loop last week and I thought it might have gotten lost in the 
flood.  Or maybe I just can't take a hint...

---

I'm dealing with a server with several versions of MapServer on it.  We 
are serving PNGs from the filesystem via CGI and working to speed up 
performance.  I've been trying gdaladdo (-r nearest) to create overviews 
for each image.  Mainly this works great and does give us the speed 
increase I'm after.

However, some of the MS versions on this box balk once I create an OVR 
file on any given PNG.  Upon calling the PNG in question, I get a 500 
"Internal Server error" error from Apache (2.0.46).  So the exact same 
CGI call works without an OVR file and gives me the 500 error with an 
OVR file present.  The Apache error logs don't contain a record of the 
500 error.  This is an issue because several existing web service hit 
the problematic (and newer) version of MapServer and I don't want to 
roll back to an older version which might have its own performance costs.

I'm a bit baffled - anyone else seen this kind of error with overview 
files?  I'd like some possibilities before I go back to the sys admin of 
the machine in question.  Sorry I can't provide more details, but it is 
not my box.  Thanks so much folks - apologies for the sketchy details...

Jesse


This version of MapServer always works, *.OVR present or not:
MapServer version 4.1 OUTPUT=PNG OUTPUT=JPEG OUTPUT=WBMP SUPPORTS=PROJ 
SUPPORTS=FREETYPE SUPPORTS=WMS_SERVER SUPPORTS=WMS_CLIENT 
SUPPORTS=WFS_SERVER INPUT=EPPL7 INPUT=POSTGIS INPUT=OGR INPUT=GDAL 
INPUT=SHAPEFILE


This version of MapServer only works with no *.OVR file present:
MapServer version 4.4.0 OUTPUT=PNG OUTPUT=JPEG OUTPUT=WBMP OUTPUT=PDF 
SUPPORTS=PROJ SUPPORTS=FREETYPE SUPPORTS=WMS_SERVER SUPPORTS=WMS_CLIENT 
SUPPORTS=WFS_SERVER SUPPORTS=WFS_CLIENT INPUT=EPPL7 INPUT=POSTGIS 
INPUT=OGR INPUT=GDAL INPUT=SHAPEFILE

-- 
Jesse A. Cleary
Department of Marine Sciences
UNC Chapel Hill

334 Chapman Hall
(919) 962-4987
jcleary at email.unc.edu