On Fri, Oct 16, 2009 at 10:37 AM, Jörn Kottmann <[email protected]> wrote: > Jaroslaw Cwiklik wrote: >> >> In your particular case ( node dying), getting a message in a >> transactional >> context could have helped. Transactions are not "free" and I certainly >> would >> not want to use them by default. Transactions have impact on performance. >> We >> could enable transactional JMS session using a configuration setting. >> Perhaps via -D. >> > > Sure, do you think transactions are really expensive and slow the > system down ? > > Otherwise it might be better to have a cluster master which just keeps > track of everything. > > I also noticed that client node failure is difficult to handle, because then > you loose > track of the of the pending CASes, which are processed right now. > And if the cluster master fails?
> Our system reads from a work queue which is feed by a different system, > then the work item is wrapped in a CAS and sent to the uima-as cluster, when > the client > gets the work back from the cluster the result is sent to another queue. > If now the client crashes (dies) we do not get back the CASes already sent > to the cluster > but have not returned yet. To improve that situation it would be cool if > UIMA AS could > guarantee that every CAS which was sent to the cluster can also be retrieved > from it, > even in case the client crashes (or a worker node dies). Our use case would > be really simple if UIMA AS just defines > two queues, one to feed it and one to read results form it (I think it is > nearly done like that right now). UIMA AS uses temporary queues to create unique reply queues for any number of clients running on the same or multiple nodes, as well as cleaning up broker resources created by clients. > The part which reads the result from uima-as must not necessary run in the > same process (or machine) as the > part which feeds it. > How about creating a service that all worker nodes call at the of their processing pipelines to save the results and or status? Or using a shared filesystem for final results? Eddie
