NetKernel + Kowari "NetKernel has a great pipes/filters framework for composing services. Kowari is the only non-rdbms backed RDF triple-store with support for queries against datetime data types.
Sadly, building a web application or service in Kowari kinda sucks. But, theoretically, Kowari is embeddable. So I set out to verify this assertion and to gain more knowledge about the inner workings of NetKernel."
"Fourth, NetKernel is really just that, a kernel for managing the interaction and scheduling between components executing in the vm, called modules. But I haven't found support for explicit life-cycle management. That is, there is no init(), start() or stop() type methods on a module. It seems to rely on finalizers to clean up resources. Thus, shutting down a NetKernel instance corrupts the Kowari database."
Like I said in the comments, previously commited data will be there no matter if you kill the process, turn off the power or whatever. However, if you stop it during a load or if autocommit is off it won't be there when restarting.