Can anybody help me to explain the performance between Stateful and Stateless session? I write a very simple test code to test the performance: Just a message,if the id is odd then set a attribute to "odd" if it is even then set to "even". insert message one by one, and insert 1,000,000 times. Rule: rule "even" when message: Message() eval((message.getId() % 2) == 0) then message.setOddOrEven("odd"); end rule "odd" when message: Message() eval((message.getId() % 2) == 1) then message.setOddOrEven("even"); end message class just id and oddOrEven public class Message { private int id; private String oddOrEven; public Message(int id){ this.id = id; } // getter and setter } My test code: // create statefulSession and statelessfulSession out of KnowledgeBase StatefulKnowledgeSession statefulSession = kbase.newStatefulKnowledgeSession(); StatelessKnowledgeSession statelessfulSession = kbase.newStatelessKnowledgeSession(); int messageNumber = 1000000; // total message number Random random = new Random(); // to generate id long begin = System.currentTimeMillis(); for(int i = 0; i < messageNumber; i++){ FactHandle handle = statefulSession.insert(new Message(random.nextInt())); statefulSession.retract(handle); } statefulSession.dispose(); long end = System.currentTimeMillis(); long statefulTime = end - begin; begin = System.currentTimeMillis(); for(int i = 0; i < messageNumber; i++){ statelessfulSession.equals(new Message(random.nextInt())); } end = System.currentTimeMillis(); long statelessTime = end - begin; System.out.println("Stateful session time: " + statefulTime + " Stateless session time: " + statelessTime); The result: "Stateful session time: 12158 Stateless session time: 46" oh my god... Is there any place is wrong in my code ? -- View this message in context: http://drools.46999.n3.nabble.com/Performance-Stateful-vs-Stateless-Sessi... Sent from the Drools: User forum mailing list archive at Nabble.com.