Re: [rules-users] drools performance with <

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