Hi Thomas,
since you have 10 GB of RAM for all of the tasks running on your computer, I doubt that 9800 MB for Java/mkgmap is actually feasable. With Win 7, I put away some 1200-1500 MB for the operating system.
If a process gets more memory, swapping to disk will occur, which is a slow process, and the garbage collection might fail in such situations (well, not sure for Java, but I saw such situations with .Net).
I do not know how much RAM will be used up by WIN 10, but I think replacing "-Xmx9800m" by "-Xmx8500m" could be worth a test; you could also (additionally) set the initial heap size to that amount ("-Xms8500m") .
Bernhard

Am 24.03.2017 um 17:07 schrieb Thomas Morgenstern:

Hi, I have a W10, 64 bit machine and 10 GB RAM. Since a few months i can not generate the mdr-file for Europa from www.Download.Geofabrik.de In a first run i generate only all the maptiles. No Problem. in a second i will generate the overview, tdb and mdr. I start java -Xmx9800m -XX:-UseGCOverheadLimit jar mkgmap.jar code-page=1252 -family-id=1901 -x-split-name-index -index D:\Karten\Europa\*.img.

and get the error.

with mkgmap-r3864 it get the same error.

How many RAM must i have for Europa complete ?. In august 2016 it was possible to create the mdr with 6 GB RAM. But the filesize is growm ...

thomas