Hi, all: I'm a newbie to Drools. I'm trying to restore stateful knowledge session using JPAKnowledgeService after restarting server. In my rules I use Drools Fusion's Sliding Length Window to processing events. Below is a sample: package com.sample import com.sample.Event; import java.util.List; declare Event @role(event) end rule "test" when $list : List() from collect(Event() over window: length(2)) then System.out.println("list size:" + $list.size()); end And I have done what should be done according to the manual reference. When I running my test case below: @Test public void test_persistedsession() { KnowledgeBase kbase = KnowledgeBaseFactory.newKnowledgeBase(); loadDRL(kbase); Environment env = KnowledgeBaseFactory.newEnvironment(); env.set( EnvironmentName.ENTITY_MANAGER_FACTORY, Persistence.createEntityManagerFactory( "org.drools.persistence.jpa" ) ); env.set( EnvironmentName.TRANSACTION_MANAGER, TransactionManagerServices.getTransactionManager()); //create a persisted statefulknowledgesession StatefulKnowledgeSession ksession = JPAKnowledgeService.newStatefulKnowledgeSession(kbase, null, env); ksession.insert(new Event()); ksession.fireAllRules(); ksession.insert(new Event()); ksession.fireAllRules(); //reload the persisted session ksession = JPAKnowledgeService.loadStatefulKnowledgeSession(ksession.getId(), kbase, null, env); ksession.insert(new Event()); ksession.fireAllRules(); ksession.insert(new Event()); ksession.fireAllRules(); } Then I found that the result is: Hibernate: insert into SessionInfo (id, lastModificationDate, rulesByteArray, startDate, OPTLOCK) values (null, ?, ?, ?, ?) Hibernate: update SessionInfo set lastModificationDate=?, rulesByteArray=?, startDate=?, OPTLOCK=? where id=? and OPTLOCK=? *list size:1* Hibernate: update SessionInfo set lastModificationDate=?, rulesByteArray=?, startDate=?, OPTLOCK=? where id=? and OPTLOCK=? Hibernate: update SessionInfo set lastModificationDate=?, rulesByteArray=?, startDate=?, OPTLOCK=? where id=? and OPTLOCK=? *list size:2* Hibernate: update SessionInfo set lastModificationDate=?, rulesByteArray=?, startDate=?, OPTLOCK=? where id=? and OPTLOCK=? Hibernate: update SessionInfo set lastModificationDate=?, rulesByteArray=?, startDate=?, OPTLOCK=? where id=? and OPTLOCK=? *list size:3* Hibernate: update SessionInfo set lastModificationDate=?, rulesByteArray=?, startDate=?, OPTLOCK=? where id=? and OPTLOCK=? Hibernate: update SessionInfo set lastModificationDate=?, rulesByteArray=?, startDate=?, OPTLOCK=? where id=? and OPTLOCK=? *list size:4* Hibernate: update SessionInfo set lastModificationDate=?, rulesByteArray=?, startDate=?, OPTLOCK=? where id=? and OPTLOCK=? As I have declared that the length of window is 2, how can the size of list increase to 3, 4 and more? I am using the 5.2.0 final. May be I have missed something, please help me. Any help will be appreciated. -- View this message in context: http://drools.46999.n3.nabble.com/persisted-StatefulKnowledgeSession-fail... Sent from the Drools: User forum mailing list archive at Nabble.com.