[Qgis-user] pegged CPU and vast RAM usage saving Layer Definition File

[Greg Troxel]

I am using qgis 3.28.7, built under pkgsrc on NetBSD 9 amd64.  Generally
things work well, aside from this problem.  My machine has 24 GB of
RAM.

For plugins I have QField, geoscience, Lat Lon Tools, CoGo, DB Manager,
Numeric Digitize, Quick Map Services, Quick OSM, SLYR CE.  None of that
seems unusual.


I have "all.qgz" which is basically a project where I stick everything
of interest so I can click them on and off.  My data, and a lot of
layers from MassGIS (government GIS agency).  Some are in postgis, and a
lot of shapefiles, some very large.


I have been saving this as .qld so that I can create projects for
specific usages with a reduced layer set.  (Motivated in part by QField,
but QField, other than the plugin being installed, is not part of the
issue.)

For a lot of layers, I successfully created .qlr files:

  DHS-nursing-homes.qlr
  carto-basemap-osm-tms.qlr
  massgis-MAD-TRAILS.qlr
  massgis-basemap-tms.qlr
  massgis-imagery-2019-tms.qlr
  massgis-imagery-2021-tms.qlr
  massgis-lidar-shaded-relief-old-tms.qlr
  massgis-lidar-shaded-relief-tms.qlr
  massgis-lidar-slope-tms.qlr
  massgis-parcels-tms.qlr

some are TMS, some are local shapefiles.  I also have a bunch for
private data in gpkg, and some georeferenced tiffs, etc.

At some point, I started having trouble with "save as layer definition
file".  When it works it is very fast, as I would expect it's just
writing out information that is handy in memory.  In particular I do not
expect it to iterate over the data.   This was under .6, and I just
updated to .7.


When it doesn't work, qgis uses 100-150% CPU (meaning 2 threads at
times), and the memory usage climbs rapidly, from maybe a few GB to as
high as 50 GB, with RSS staying maybe around 10 GB.   This starts to
make the machine unhappy overall and I kill it.

Obviously I need to debug, but I wonder:

  is anyone else having problems saving qlr files?

  is my assumption that qgis does not read a layer's entire data valid?

  is it true that plugins are not in the loop when saving qlr?

  any other clues?

Thanks,
Greg