Re: [rules-users] Is RETE algo optimizes the performance in a stateless session.

Hi All, Thanks to Leo and Mark for the help... Please find my comments(blue) inline. Crisp question: *Is there any functionality in drools where I can run the rules(stateless session) in parallel threads to increase the throughput ?* Note: The rules actions won't change the facts/data such that it would require running of the rules again. Hence I came to this conclusion that stateless sessions are required. 2010/9/24 Leonardo Gomes <leonardo.f.gomes(a)gmail.com&gt; > Hello Harshit / Mark, > > My reasoning behind the yes, is that: > > - If you have 10 rules that won't necessarily always match, it's better to > use Rete, than sequentially match one-by-one. The tree structure with the > sharing of nodes for different rules seems to always be a better approach > for me, than sequentially testing one-by-one and, in some cases, retesting > the same condition on different rules (if that happens); > > In my use case, the overlap of sub-conditions is not much. There would be only few conditions which will have common sub conditions and the no of sub conditions would be max 5. After reading the articles, I agree with Leo that still its better to use RETE than sequentially testing one by one. Also the rules actions won't change the facts/data such that it would require running of the rules again. Hence I came to this conclusion that stateless sessions are required. I have jotted down the applicable reasons for me to use the rule engine (based on my readings on drools & rete) : 1. separation of business logic from application logic. 2. rules are flexible and likely to be changed overtime. My requirements would be satisfied by using stateless session functionality of drools. Questions: *Is there any functionality in drools where I can run the rules in parallel thread to increase the throughput ?* (I can use java threads to run the rules separately in different threads but would like to know if there is any optimization approach in drools for stateless sessions) - You can write if-then-elses in a imperative language and perform better > than Rete, but if your rules are complicated and you have many of them, it's > likely that rete can do a better job; Also, if you need to change your rules > or add new ones, it will be easier to do that declaratively; > > I think here you are suggesting that using a rule engine would be better. (based on ur comments on the need to change rules, add new ones) I first put the links, because you can use that to judge yourself whether > or not you might gain in performance in your own scenarios, with that > material. > > Thanks Leo. It really helped me to improve my understanding of the algorithm. > > @Mark: > > In general a stateless session is just a convenience api for stateful, it >> just wraps. So no performance gain at all. > > > I think here you're saying that there will be no performance gain compared > to a stateful session, but I believe that the question was more on the lines > of "I know that with a stateful it's efficient, how about stateless". I > tried to say that, yes, it's also worth using Rete in stateless scenarios. > > Mark, I meant the same what Leo explained. Cheers, > Leo. > > 2010/9/24 Mark Proctor <mproctor(a)codehaus.org&gt; > > On 24/09/2010 16:18, Leonardo Gomes wrote: >> >> Have a look here: http://www.drdobbs.com/184405218 >> >> here: http://blog.athico.com/2007/07/sequential-rete.html >> >> and here: http://herzberg.ca.sandia.gov/guidelines.shtml >> >> The easy answer for your question is "Yes" ;-) >> >> It depends :) >> >> In general a stateless session is just a convenience api for stateful, it >> just wraps. So no performance gain at all. >> >> There is a "sequential" mode, but in all honest you won't get any >> measurable perf gain. So I wouldn't use sequential mode for performance, the >> only reason to use it is if you want your rules to execute sequentially. >> >> Mark >> >> >> Cheers, >> Leo. >> >> 2010/9/24 Harshit Bapna <hrbapna(a)gmail.com&gt; >> >>> Hi All, >>> >>> In a scenario where lets say 10 rule are to be fired (in any order) in a >>> stateless session than will I get the benefits of RETE algorithm (i.e >>> increased performance). >>> i.e Whether the engine will fire all the ten results in a parallel >>> fashion or Whether the engine will file each rule one by one. >>> >>> How RETE algorithm will improve the performance of the engine for rules >>> fired in stateless session ? >>> >>> >>> _______________________________________________ >>> rules-users mailing list >>> rules-users(a)lists.jboss.org >>> https://lists.jboss.org/mailman/listinfo/rules-users >>> >>> >> >> _______________________________________________ >> rules-users mailing listrules-users@lists.jboss.orghttps://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 >> >> > > _______________________________________________ > rules-users mailing list > rules-users(a)lists.jboss.org > https://lists.jboss.org/mailman/listinfo/rules-users > > -- -- Harshit Bapna _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users