[gdal-dev] vrt: prevent opening all source files on open?

[Vincent Schut]

Hi,

Is there a way (or: what are the prerequisites) to avoid gdal opening 
all source files from a vrt on opening the vrt?

Context: I have created a large vrt, referencing many tif files. Both 
the vrt and tifs are remote (using /vsigs/). It works, but opening (e.g. 
running gdalinfo) is very slow.

I have a comparable vrt where the main difference is that it references 
.hgt files instead of tifs. Running gdalinfo on this vrt is almost 
instantaneous.

As there are no other significant differences otherwise, I wonder if 
this is because if the vrt machinery encounters a tif, it starts to 
check if there are any accompanying overviews (or other important 
metadata), while it does not do that for a .hgt file? Or is there a 
different reason? And how can I prevent this (without, preferably, 
changing to a different source file format)?

Thanks,
Vincent.