[gdal-dev] gdalinfo on large vrt takes a long time

[Even Rouault]

William,

it might be perhaps related to the GetMinimum() call done by gdalinfo. 
Cf https://trac.osgeo.org/gdal/ticket/5444

But normally it should only try to open the first source, and not all of 
them. At least that's what I could confirm on a quick testing. But I do 
see that the CanUseSourcesMinMaxImplementations() method will stat() 
sources whose filename looks like a local file (obviously if that's a 
mounted file system / vpn thing, it will not realize it is remote).

Try setting the VRT_MIN_MAX_FROM_SOURCES=NO environment variable / 
configuration option to see if that makes a difference. If it does, the 
CanUseSourcesMinMaxImplementations() logic should be modified to avoid 
doing those stat's().

If that's confirmed to be linked to GetMinmum(), you may also workaround 
the issue by doing a "gdalinfo -stats the.vrt" (from the server) to have 
statistics incorporated in the VRT, then GetMinimum() should be instant

Even

Le 09/06/2023 à 00:43, William Kyngesburye a écrit :
> I'm writing a script that needs some info from a vrt raster, and one has thousands of files. When reading the vrt over the internet (vpn to our server) it takes a long time. I think it's looking at every file of the vrt.  What is gdal reading from the files that's not in the vrt itself? I used all the -no options and I'm not adding any other info options like checksums or stats. I just need basic info from the vrt that's in the vrt file.
>
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