[rules-users] Needs advice to help Drools on a big problem (and avoid GC overhead)

[Raphael Jolivet]

Hmm, sure it makes sense. The operations and resources are independent. I
think I can safely split the problem into smaller ones. I will try this
approach.

Thanks for the tip
Le 20 mars 2014 20:51, "Wolfgang Laun" <wolfgang.laun at gmail.com> a écrit :

> I may fail to understand the fundamentals of this problem, but it seems
> to me that it doesn't have the dynamic requirements that would
> warrant a full "blow up" of all Resources and Operations at the same time.
>
> We have the 300 rules, and I'm assuming that the pattern is the one
> shown in OP's mail: a Resource subset times an Operation subset. So,
> if you insert just one Resource (or Operation) fact together with
> all Operation (or Resource) facts and fire all rules, you'll get all
> Forbids
> for the one Resource with all Operations (or vice versa). Then, you
> retract the singleton and insert the next one, fire all rules, and so on.
>
> -W
>
>
> On 20/03/2014, Raphael Jolivet <raphael.jolivet at gmail.com> wrote:
> > Thanks for you quick answer.
> >
> > Not yet,
> >
> > For that I will need to switch to fact insertion instead of Java Set.
> > Do you think to will make a difference in the way the RETE Tree will be
> > built ?
> >
> >
> >
> >
> > 2014-03-20 20:27 GMT+01:00 Mark Proctor <mproctor at codehaus.org>:
> >
> >> Did you try using the engine in equality mode? It will only ever allow
> >> one
> >> "equal" object to be inserted, others are just ignored.
> >>
> >> Mark
> >> On 20 Mar 2014, at 18:54, Raphael <raphael.jolivet at gmail.com> wrote:
> >>
> >> > Hi,
> >> >
> >> > In our project, we use Drools to compute forbidden allocations as
> input
> >> for
> >> > an allocation problem  (for which we do not use Drools BTW).
> >> >
> >> > The constraint of the problem (forbidden operation for given
> resources)
> >> are
> >> > expressed as drools rules.
> >> >
> >> > We have about
> >> > -200 resources
> >> > -700 operations
> >> >
> >> > Those are the Drools facts.
> >> > We have about 200 Drools rules describing the forbidden allocations
> >> >
> >> > The problem here is that many rules produce duplicates forbids.
> >> > For instance :
> >> > Rule 1 may forbid Op1 on Res1 & Res3
> >> > Rule 2 may forbid Op1 on Res2 & res3
> >> >
> >> > Currently the RHS of rules just insert forbids into a pure Java Set
> (no
> >> fact
> >> > insertion).
> >> > The Set takes care of avoiding duplicates, but still, we feel we could
> >> help
> >> > Drools by giving him a hint that
> >> > all rules are actually producing pairs of <Resource, Allocation> and
> >> that he
> >> > should not try to produce them more than once.
> >> >
> >> > Currently the structure of each rule looks like that :
> >> >
> >> > when
> >> > $resource : Resource(<someconditions>)
> >> > $operation : Operation(<someconditions>)
> >> > then
> >> >  globalSet.add(Pair<resrouce, operation>)
> >> > end
> >> >
> >> > With the size of the problem, we often end up with outOfMem/ GC limit.
> >> > When analyzing memory dump, we see about
> >> > 300.000 drools left tuple object.
> >> >
> >> > I am not sure if we could help drools to reduce the Rete tree here.
> >> > I mean, the allocation matrix is already : 200*700 = 140.000 cells.
> >> > Drools only uses 2 nodes for each possible forbids, which seems
> already
> >> well
> >> > optimized.
> >> >
> >> > We had several idea to improve that though, but we are not enough
> >> > expert
> >> in
> >> > the internal of the RETE algorithm to decide if that's a good way to
> go
> >> > :
> >> >
> >> > 1) Insert forbids as facts in the RHS and check they are not already
> >> there
> >> > in the LHS :
> >> > when
> >> > $resource : Resource(<someconditions>)
> >> > $operation : Operation(<someconditions>)
> >> > not Forbid(res=$resource, op=$operation)
> >> > then
> >> >  insert(Forbid($resource, $operation))
> >> > end
> >> >
> >> > 2) Merge all rules in one big rule with a single RHS
> >> > Is it possible to have something like :
> >> > when
> >> > // Rule 1
> >> > ($resource : Resource(<someconditions>)
> >> > $operation : Operation(<someconditions>))
> >> >  or
> >> > // Rule 2
> >> > ($resource : Resource(<someconditions>)
> >> > $operation : Operation(<someconditions>))
> >> > // Etc ...
> >> > then
> >> >  globalSet.add(Pair<resrouce, operation>)
> >> > end
> >> >
> >> > 3) Define a common RHS somewhere and tell Drools all rules use this
> >> > one.
> >> > Is there a possibility in Drools to define reusable RHS ? Would it
> help
> >> > ?
> >> >
> >> > 4) Any other idea ?
> >> >
> >> >
> >> > Thanks in advance for your help.
> >> > Brgds,
> >> >
> >> > Raphael Jolivet
> >> >
> >> >
> >> >
> >> >
> >> >
> >> >
> >> >
> >> >
> >> >
> >> >
> >> >
> >> >
> >> >
> >> >
> >> >
> >> >
> >> >
> >> >
> >> >
> >> >
> >> >
> >> >
> >> > --
> >> > View this message in context:
> >>
> http://drools.46999.n3.nabble.com/Needs-advice-to-help-Drools-on-a-big-problem-and-avoid-GC-overhead-tp4028838.html
> >> > Sent from the Drools: User forum mailing list archive at Nabble.com.
> >> > _______________________________________________
> >> > rules-users mailing list
> >> > rules-users at lists.jboss.org
> >> > https://lists.jboss.org/mailman/listinfo/rules-users
> >>
> >>
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