Do you have rules which relate two arbitrary customers together? If the answer is no (and even a limited yes) then the problem can process customers in parallel. That means you can break the processing down into smaller chunks and you don't need all customers in memory at once. GreG On Sep 9, 2010, at 3:27, bellios <carfid(a)gmail.com&gt; wrote: In my application I would to model the Customers-Sales domain and I thought that drools could help me to express a set of rules to capture (or execute on-demand) some "special" customers (e.g. take the customers which not have/have bought some products of category X in the last 6 months). To do this i'm loading the last 6 months sales into WM, afterwards on demand i execute the rules. This process fails due the memory requirements. I thought that Drools would use an hibernate/JPA/ or an incremental mechanisms to load and process the facts. @Swindells, Thomas: Do you think that it's the right approach? @Michael Anstis-2: I will try to study in deep the event processing\CEP\streaming methods. -- View this message in context: http://drools-java-rules-engine.46999.n3.nabble.com/Loading-facts-and-mem... Sent from the Drools - User mailing list archive at Nabble.com. _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users