Hi On Wed, Aug 10, 2011 at 12:25 PM, Marco Hugentobler <marco.hugentob...@sourcepole.ch> wrote: >> 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. > > But is there any downside from populating min/max on demand (e.g. like in > QgsVectorDataProvider::minimumValue / maximum Value)? > > While it's nice to have a minimal overhead (probably buffered by the qgis > server layer cache in many cases), it would be even better to have 0 overhead. >
Ya you make a good point. I will try update it to calculate on demand. Regards Tim > Regards, > Marco > >> Am Mittwoch, 10. August 2011, 11.50:16 schrieb Tim Sutton: >> 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 > > > -- > 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