Hi On Wed, Aug 10, 2011 at 8:31 AM, Marco Hugentobler <marco.hugentob...@sourcepole.ch> wrote: > Btw, is it possible to call computeMinMax() on demand, e.g. in > QgsGDALProvider::minimumValue /maximumValue instead of the provider > constructor? > > It probably does not matter much for the desktop experience. However, for > server throughput, avoidance of opening and parsing the aux.xml file could > make > a difference. >
I think the overhead for reading the aux.xml file is really minimal and the min/max population of that if its not there is quite quick and a once off event so I wouldnt think it is going to impact the server much. I'd suggest I first run some benchmarks to see how much overhead it adds. Regards Tim > Regards, > Marco > > > Am Dienstag, 9. August 2011, 21.46:45 schrieb Tim Sutton: >> Hi Paolo >> >> Does it do that every time you load that layer or only the first time? >> Does the filesystem permissions allow writing of gdal .aux.xml files? >> >> My raster stats branch merge changed some behaviours and it is >> probably a side effect of that. One of the changes is that gdal gets >> full stats when trying to determine the min max of a band. It will >> fetch those stats quickly from aux.xml if present of if not its going >> to do a full stats gather just for the basic min max stats which is >> where you probably experience the slowness. I will see if I can find a >> better way to do the basic min/max stats gathering. >> >> Regards >> >> Tim >> >> On Tue, Aug 9, 2011 at 3:49 PM, Paolo Cavallini <cavall...@faunalia.it> > wrote: >> > Hi all. >> > With current master, I get bad performances in loading rasters (a <12Mb >> > takes >5 sec); when double-clicking it from the QGIS browser, it is far >> > slower (>20 sec). From the console: >> > Warning: Object::connect: No such signal QgsGdalProvider::statusChanged( >> > QString ) in >> > /storage/build/Quantum-GIS/src/core/raster/qgsrasterlayer.cpp:2446 Any >> > hint? >> > All the best. >> > -- >> > Paolo Cavallini: http://www.faunalia.it/pc >> > _______________________________________________ >> > Qgis-developer mailing list >> > Qgis-developer@lists.osgeo.org >> > http://lists.osgeo.org/mailman/listinfo/qgis-developer > > > -- > Dr. Marco Hugentobler > Sourcepole - Linux & Open Source Solutions > Churerstrasse 22, CH-8808 Pfäffikon SZ, Switzerland > marco.hugentob...@sourcepole.ch http://www.sourcepole.ch > Technical Advisor QGIS Project Steering Committee > -- Tim Sutton - QGIS Project Steering Committee Member (Release Manager) ============================================== Please do not email me off-list with technical support questions. Using the lists will gain more exposure for your issues and the knowledge surrounding your issue will be shared with all. Visit http://linfiniti.com to find out about: * QGIS programming and support services * Mapserver and PostGIS based hosting plans * FOSS Consulting Services Skype: timlinux Irc: timlinux on #qgis at freenode.net ============================================== _______________________________________________ Qgis-developer mailing list Qgis-developer@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-developer