I'm seeing this issue with an instance that is running on Ubuntu 18.04 with stardog 7.6.3 installed via the debian installer. I started seeing this issue after having an out of memory error when querying a large virtual graph.
Here is the error I saw:
INFO 2021-05-11 18:11:44,888 [main] com.complexible.stardog.virtual.DefaultVirtualGraphRegistry:syncCache(494): Initializing virtual graph registry
I let the server try to startup and it was pinned at 100% on 1 cpu for over 4 hours. Even using -v the only output I saw was the above in stardog.log.