[rules-users] Sessions Sharing KnowledgeBase

Hello, I am trying to create multiple sessions, and for each session I will load one knowledge package representing one drl. Each drl may optionally load additional knowledge packages (drls). Since all sessions will be accessing the same list of knowledge packages, and since they take a long time to compile resources, I decided to create a Map with all possible knowledge packages that all sessions may use. That worked beautifully saving me compilation time (it is done at start up). Now, here is how I am creating the static map: private static ConcurrentMap<String, KnowledgePackage> knowledgePackages = new ConcurrentHashMap<String, KnowledgePackage>(); Here is how I am initializing it: KnowledgeBuilder kbuilder = null; for (MedCPUKnowledgeBase medcpuKnowledgeBase : medcpuKnowledgeBases) { try { kbuilder = KnowledgeBuilderFactory.newKnowledgeBuilder(); // This call actually compiles the drl file. kbuilder.add(ResourceFactory.newClassPathResource(medcpuKnowledgeBase.getFileName()), ResourceType.DRL); KnowledgeBuilderErrors errors = kbuilder.getErrors(); if (errors.size() > 0) { ..... } else { knowledgePackages.put(medcpuKnowledgeBase.getFileName(), [the package just added above]); } } catch(Exception ex) { .... } else { ..... } } } Each session will do this to get the pre-compiled KnowledgePackage: KnowledgePackage knowledgePackage = knowledgePackages.get(kb); ...... Collection<KnowledgePackage> packages = new ArrayList<KnowledgePackage>(); packages.add(knowledgePackage); // The problem is this guy (after a relatively small number of requests each opening a new session) just gets stuck!! It does not throw an exception and it does not return. this.knowledgeBase.addKnowledgePackages(packages); When I did not share the KnowledgePackages like I did above, I was able to get thousands of requests with each having its own session, knowledgebase, and its own knowledge packages after they compile the respective drls. However, because this was slow compiling the same drls over and over again I switched to the design above which after only 20 or 30 requests it gets stuck on the line above. I still have a knowledgebase per session per request, but now I am sharing the knowledge packages. I cannot find anywhere where it says that KnowledgePackage objects are not thread-safe (not safe to be shared between sessions/threads). Any idea why I am stuck on the line above? Thanks! -- View this message in context: http://n3.nabble.com/Sessions-Sharing-KnowledgeBase-tp96894p96894.html Sent from the Drools - User mailing list archive at Nabble.com.