Hi Andy, Thanks for your answer. The dataset cleanup operation I am referring to is just closing a database pool.
Given that my custom dataset is read-only, after an abnormal server shutdown, I would expect no dataset recovery actions are needed and the only impact would be a few open connection pools. Despite that the latter cannot be avoided, I think it's still beneficial to try to handle graceful shutdown by closing the open pools. On Sun, Dec 27, 2020 at 7:18 PM Andy Seaborne <a...@apache.org> wrote: > Hi Dimitris, > > On 27/12/2020 14:08, Dimitris Spanos wrote: > > Hi all, > > > > I was wondering if there is a registry in ARQ or Jena base that keeps > track > > of all registered datasets? > > There isn't. > > > Such a registry would be helpful, since I have a custom > > Dataset/DatasetGraph implementation and I would like to perform some > > resource cleanup during JenaSubsystemLifecycle.stop() for every dataset. > > I am aware of DataAccessPointRegistry but from an architectural point of > > view, I would not want my Jena submodule to depend on Fuseki. > > Any dataset implementation has to survive reality.:-) > > Reality includes (machine|process|JVM) crashes, "kill -9" and > System.exit(0) and nasty things in transactions like out of disk space. > > Datasets have to cope with unexpected stops. For example, when a TDB(1 > or 2) dataset starts, it check whether any recovery actions are needed > and does them as it starts, > > Because that happens, clean shutdown can only be an "extra". Once you > trust the recovery, adding clean shutdown is extra work. > > What sort of clean shutdown does you dataset impl wish to do? > > Andy > > > Right now, I have implemented a Singleton dataset registry for my custom > > datasets (registration happens during dataset assembly), but I am curious > > to know if there is another/better way to retrieve registered datasets. > > > > Regards, > > Dimitris > > >
