Hi Patrick, Would be interesting to do this test with previews enabled and disabled. Then we'll see if it's actually the previews or some other mechanism that is causing this.
IIRC only a composite image is saved in the preview jobs and not each layer separately, but that's just what I remember and not evidence based. You can enable them in the python console with iface.mapCanvas().setPreviewJobsEnabled(True) and disable with iface.mapCanvas().setPreviewJobsEnabled(False) Thanks for a feedback Matthias On 11/16/2017 08:42 AM, Patrick Dunford wrote: > > In my current project using Qgis 2.99, turning off the rasters uses 16 > GB, turning them on uses 52 GB > > I do not believe it is independent from the number of layers that are > being displayed. > > Previous versions of the software did not cache every single raster > (the number of rasters actually being displayed on the canvas at any > one time is a small fraction of the total number in the project) > > On 16/11/17 20:11, Matthias Kuhn wrote: >> >> Hi Patrick, >> >> This uses some memory (~ canvas width pixels * canvas height pixels * >> 8 preview images * 32 bit RGBA), so let's assume 50 MB to 100 MB. >> >> This consumption is independent from the number or type of layers. >> >> Matthias >> >> >> On 11/16/2017 08:02 AM, Patrick Dunford wrote: >>> >>> So to put it another way this is the reason why Qgis wants to use a >>> huge amount of memory (40 GB) when I have a lot of raster images >>> loaded in the background. >>> >>> >>> On 16/11/17 18:56, Tim Sutton wrote: >>>> Hi >>>> >>>>> On 16 Nov 2017, at 04:35, Patrick Dunford <enzedrailm...@gmail.com >>>>> <mailto:enzedrailm...@gmail.com>> wrote: >>>>> >>>>> What is this "preview job" function? >>>>> >>>>> >>>> >>>> Its application logic to prefetch / pre-render offscreen content in >>>> anticipation of user panning the map. >>>> >>>> Regards >>>> >>>> Tim >>>>> >>>>> _______________________________________________ >>>>> QGIS-Developer mailing list >>>>> QGIS-Developer@lists.osgeo.org <mailto:QGIS-Developer@lists.osgeo.org> >>>>> List info: https://lists.osgeo.org/mailman/listinfo/qgis-developer >>>>> Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-developer >>>> >>>> — >>>> >>>> >>>> >>>> >>>> >>>> >>>> *Tim Sutton* >>>> >>>> *Co-founder:* Kartoza >>>> *Project chair:* QGIS.org <http://QGIS.org> >>>> >>>> Visit http://kartoza.com <http://kartoza.com/> to find out about >>>> open source: >>>> >>>> Desktop GIS programming services >>>> Geospatial web development >>>> GIS Training >>>> Consulting Services >>>> >>>> *Skype*: timlinux >>>> *IRC:* timlinux on #qgis at freenode.net <http://freenode.net> >>>> >>> >>> >>> >>> _______________________________________________ >>> QGIS-Developer mailing list >>> QGIS-Developer@lists.osgeo.org >>> List info: https://lists.osgeo.org/mailman/listinfo/qgis-developer >>> Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-developer >> >> >> >> _______________________________________________ >> QGIS-Developer mailing list >> QGIS-Developer@lists.osgeo.org >> List info: https://lists.osgeo.org/mailman/listinfo/qgis-developer >> Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-developer > > > > _______________________________________________ > QGIS-Developer mailing list > QGIS-Developer@lists.osgeo.org > List info: https://lists.osgeo.org/mailman/listinfo/qgis-developer > Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-developer
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