I'm not sure I understand this advice-- are you saying that because no DatasetGraph can be assumed to support MR, there isn't any point in trying to support MR at the level of DatasetGraphWithRecord? That would seem to make my whole effort a bit pointless.
Or are you saying that because, in practice, all DatasetGraphs _do_ support MR, there's no need to enforce it at the level of DatasetGraphWithRecord? --- A. Soroka The University of Virginia Library On Jul 29, 2015, at 4:14 PM, Andy Seaborne <[email protected]> wrote: > On 27/07/15 18:06, [email protected] wrote: >>> Is there some specific reason as to why you override the >>> DatasetGraphWithLock lock? >> Yes, because DatasetGraphWithLock has no Lock that I could find, and it >> inherits getLock() from DatasetGraphTrackActive, which just pulls the lock >> from the wrapped DatasetGraph. I wanted to make sure that a MRSW Lock is in >> play. But maybe I am misunderstanding the interaction here? (No surprise! >> {grin}) >> > > A DatasetGraph provides whatever lock is suitable to meet the contract of > concurrency [1] > > Some implementations (there aren't any) may not even be able to support true > parallel readers (for example, datastructures that they may make internal > changes even in read operations like moving recently accessed items to the > top or caching computation needed for read). > > There aren't any (the rules are R-safe) - locks are always LockMRSW. > > [1] http://jena.apache.org/documentation/notes/concurrency-howto.html > > Andy >
