Well, I think the OOM trigger that prompted Linux to kill Fuseki was the fact that I had a very small swap space (1GB). After adding a new swap partition (256GB) I don't see any errors anymore (OOM or heap space).
On my PC with 16GB RAM, it used 2-3GB of swap and took approximately the same amount of time to finish as in my previous tests. On my PC with 8GB RAM, it used 9-10GB of swap and took significantly longer to finish, ~3h instead of ~2h. The good news for me is, I guess, that I've found something that works for me. On the other hand I think there is a memory problem with Fuseki because it doesn't feel right when it's using that much RAM for processing read queries in series (not in parallel). I would still love to know if there are options for forcing Fuseki into managing a given amount of RAM.
