Isn't that because SQLLite's whole use case is "simple, small, fast database that competes with fopen() and not Postgres"? At least in my experience on NTFS, unless you know the section that 2 threads are writing to, and that section is different, you can't write to a file concurrently (N.B.: in C#)

I'd be happy to be wrong (seriously that would make my day if someone could explain a clean way to do the above) but if I want to get "big boy database features" then I'd use a heavy database like SQL Server. I think it's great that there's an option like SQLLite out there for rapid prototyping and "store all your music metadata" type applications!