Re: [rules-users] drools performance with <

Please don't confuse my message with bashing Drools for not being as fast as Java. While I am not very familiar with Rete, I'm aware of what goes on behind the scenes; I've been programming declarative optimization systems for many years. My query relates to how to perform such a comparison with reasonable efficiency in Drools. Tom On Thu, Jan 21, 2010 at 7:16 PM, Greg Barton <greg_barton(a)yahoo.com&gt; wrote: > pit->out > > That falls into a rare class: two letter typos that pass a spell checker. :) > > --- On Thu, 1/21/10, Greg Barton <greg_barton(a)yahoo.com&gt; wrote: > >> From: Greg Barton <greg_barton(a)yahoo.com&gt; >> Subject: Re: [rules-users] drools performance with < >> To: "Rules Users List" <rules-users(a)lists.jboss.org&gt; >> Date: Thursday, January 21, 2010, 9:04 PM >> This is not at all surprising. >> To set up and run the rules there's quite a bit of code >> running behind the scenes besides just the comparison test. >> (For instance, there's object creation just to track the >> fact that two objects matched the rule, and in this case >> those objects are created for every possible combination of >> TestObject instances before the first rule ever fires, then >> added to lists, and so on... So in the case of 1000 >> TestObject instances, there's 1,000,000 object creations and >> list additions just for that.) >> >> So, as has been said many times on this list, and probably >> in a few blogs, for any given algorithm a hard coded java >> version will invariably be faster than rules. What >> rules gives you is a way to express solutions to complex >> problems in a flexible and comprehensible way. It >> shines when the problems are so complex that coding them >> procedurally is pit of the question. >> >> The same relationship is there between C and java. >> Java gives you managed, portable code, but for that you give >> up the raw speed of C. >> >> --- On Thu, 1/21/10, Tom Carchrae <carchrae(a)gmail.com&gt; >> wrote: >> >> > From: Tom Carchrae <carchrae(a)gmail.com&gt; >> > Subject: [rules-users] drools performance with < >> > To: rules-users(a)lists.jboss.org >> > Date: Thursday, January 21, 2010, 6:40 PM >> > Hello, >> > >> > I'm new to Drools and am trying it out. I've found >> it >> > easy enough so >> > far, but quickly ran into a performance bottleneck. >> > (perhaps an all >> > too familiar story! :) ). So, I made a simple >> example >> > to try and >> > track down the behavior. Here it is. >> > >> > I wanted to create a rule that uses an < >> comparison >> > between pairs of >> > objects. The following are the performance results: >> > >> > 10 objects. Java comparison took 0 ms >> > 10 objects. Rule firing took 2516 ms >> > 100 objects. Java comparison took 0 ms >> > 100 objects. Rule firing took 1984 ms >> > 1000 objects. Java comparison took 47 ms >> > 1000 objects. Rule firing took 132500 ms >> > 10000 objects. Java comparison took 4641 ms >> > 10000 objects. Rule firing took .... (please wait...) >> > >> > Here is the rule >> > >> > rule "A < B" >> > when >> > a : TestObject( >> > ) >> > b : TestObject( >> > valueDouble < a.valueDouble ) >> > then >> > >> > b.setValueint(b.getValueint()+1); >> > end >> > >> > Now, I do understand that this (worst-case) is a >> comparison >> > of N x N >> > objects... so, 1000 = 1000000 comparisons. However, >> > ~100ms per >> > comparison seems relatively expensive for such a >> simple >> > check. I am >> > using StatefulKnowledgeSession (I tried Stateless but >> this >> > gave only a >> > mild performance improvement - and I would also like >> to use >> > insert in >> > some of my rules). >> > >> > How would one speed up such a query? I know part of >> > the problem is >> > the < comparison. The results with == are much >> > better (presumably, it >> > can do lots of pruning of the space) >> > >> > Model creation 0 >> > 10 objects. Rule firing took 2829 ms >> > 100 objects. Rule firing took 93 ms >> > 1000 objects. Rule firing took 657 ms >> > 10000 objects. Rule firing took 3375 ms >> > 100000 objects. Rule firing took 33266 ms >> > >> > I have thought about clever tricks that I could do to >> try >> > and speed >> > things up, like sorting into groups, etc. But it >> all >> > seems relatively >> > convoluted. Am I correct in coming to the >> conclusion >> > that a < >> > comparison is not the kind of thing that you should do >> in >> > Drools? >> > >> > How would you go about this? I would prefer to keep >> > all the logic in >> > the DRL files. I'm guessing you do a Java based >> > comparison and use a >> > fire-once rule to invoke this code. >> > >> > Thanks in advance for any insight, >> > >> > Tom >> > _______________________________________________ >> > 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 >> > > > > > _______________________________________________ > 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