Wrong cache split calculation in gdal2tiles.py

[EvertEt]

Expected behavior and actual behavior.

# Make sure that all processes do not consume more than GDAL_CACHEMAX
os.environ['GDAL_CACHEMAX'] = '%d' % int(gdal.GetCacheMax() / nb_processes)

GDAL_CACHEMAX expects a value in MB but gdal.GetCacheMax() returns the value in bytes.
https://trac.osgeo.org/gdal/wiki/ConfigOptions#SettingConfigOptions
https://gdal.org/api/raster_c_api.html?highlight=getcachemax#_CPPv415GDALGetCacheMaxv

This is also confirmed by a log in gdal2tiles.py:

print("Cache: %s MB" % (gdal.GetCacheMax() / 1024 / 1024))

Steps to reproduce the problem.

See behaviour. The RAM fills up, where I assume it is because of this mismatch.

Operating system

Ubuntu 18.04 64 bit

GDAL version and provenance

The 2.4.0 version from ubuntugis-stable PPA

[rouault]

Good analysis. Can you submit a pull request to fix that ? (I'd suggest to do a max of 1 and the result of the division, to avoid a 0 cache size)

[rouault]

Fixed per #2022. Backported to branches 3.0 and 2.4