Ups, there must be some bug, or the code is very inefficient. Austria compiled fine, but when I compiled Italy using this patch versus standard trunk. Usually the 16 tiles of italy compile in 8 minutes. Now it has compiled 6 tiles in 20 minutes only. However while 5 tiles compiled in normal speed, 1 took 10 minutes and currently it is stuck again. It seems to get stuck on single tiles and max-jobs is then not continuing until the file it is stuck on finishes (only one instead of 2 cpu cores used for a long time). The one tile it took 10 minutes instead of 1 minute to compile, was also the only one with quite substantial size increase (5.07 to 5.20 MB). I'll break the rendering now and delete the following line from my relations file, maybe this is causing it to go slow? landuse=forest { apply { add landuse=forest; add name = '${name}'; add ref = '${ref}' } }