Re: TDB: Concurrent writing to named graphs

[Paolo Castagna]

Hi André,
the concurrency documentation on TDB could certainly be improved! :-)
http://openjena.org/wiki/TDB/JavaAPI#Concurrency

Can you try to get a lock from a DatasetGraphTDB and let us know if
you still have problems?

    DatasetGraphTDB dsg = ...
    Lock lock = dsg.getLock();
    lock.enterCriticalSection(Lock.READ);
    try {
         ...
    } finally {
        lock.leaveCriticalSection();
    }

Paolo


Dr. André Lanka wrote:

Hello Jena users,

we use various named graphs in a single dataset and have massive parallel write access to the named graphs. I always get a ConcurrentModificationException even if I lock on model-level using model.enterCriticalSection(boolean). By this I reckon that the MRSW pattern is applied on dataset level and not on named-graph-level. Namely, parallel writing to _different_ named graphs (constructed by dataset.getNamedModel) will always fail as the graphs use the same dataset beneath.

Could someone confirm this?

Is there any possibility to permit parallel write access to different graphs?

Thanks in advance
André