Re: [rules-users] Design guidelines regarding session pools

Mikael Larsson wrote: > Hi! > > I have some questions about multithreaded apps and if it is necessary > to pool session objects for performance. You don't need to pool session in drools, just cache the rulebase in a singleton. > > * I understand that it is expensive to create the RuleBase objects > but what about the sessions? > If I create a new stateful session object for each request will that > become a potential bottleneck? sessions are lightweight, do not pool. > > * Is the session class thread safe, what will happen if two or more > threads simultaneously call fireAllRules on one and the same session > object? sessions are thread safe, apart from the iterators. > > One advantage of pooling session is if you have some data that does > not change per request. Say that I have some data associated with a > specific type of request that should be inserted for all requests of > that particular type and evaluated towards request specific stuff, > e.g. params in the request. E.g. An object that specifies allowed > values for a particular API will be the same for all requests (well > at least until you reconfigure the allowed values...) and the rules > would evaluate the request specific value based on the "allowed > values" object. In this case only the request specific > parameter/value needs to be inserted/retracted per request. > > * I would rather use StatefulSession instead of stateless since I > find the API more flexible, are there any performance considerations > I should be aware of? If pooling is necessary I guess I must use the > stateful session. But if creating one session per request, are there > any concrete reasons for using the stateless session (besides the > simpler API and that I need to call dispose on the stateful session)? stateless just wraps stateful anyway, stateless is really just a convienience api - how stateless sessions do allow for "sequential rete" which is a performance improvement if you don't need information (fact modications leading to rule re-evaluation) but you have to go to large number of rules and objects to see a big difference with sequential rete. > > Kind of hoping that the answer will be: "No, pooling will not be > necessary.", but any feedback about situations where it may be > necessary for best performance would be much appreciated. No, pooling will not be neceesary. > > Regards, > /Mikael > > _______________________________________________ > rules-users mailing list > rules-users(a)lists.jboss.org > https://lists.jboss.org/mailman/listinfo/rules-users > _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users