I'm trying to convert an existing larger CVS repository into fossil.
The process bar from rebuild_db had reached the 100% and fossil was spending several minutes without giving any indication on what. After attaching gdb, I saw

    #2556 0x000000000040d048 in content_get (rid=11398, pBlob=<value optimized out>) at content_.c:256

in the bt output. So it seems like it is creating a stack frame for ~every CVS revision of a file. That is screaming like it should be done differently by not depending on huge stacks.