[rules-users] Lots of org.drools.common.ScheduledAgendaItem instances in memory

[Wolfgang Laun]

Just to make sure: How do you invoke the Engine? (I suppose you don't
call with a limit for rule firings.)

Unless it's a bug (BTW: your Drools version is?), it's due to one or
more of your rules.

Are you using timers? How?

A detailed investigation of the whereabouts of these
ScheduledAgendaItem objects might be done by investigating (via the
unstable API) the Agenda and its various components.

-W

On 28/05/2012, Werner Stoop <wstoop at gmail.com> wrote:
> Hi,
>
> We're using Drools with a StatefulKnowledgeSession to process events coming
> from equipment in our network. The system draws conclusions about the state
> of the equipment and writes those conclusions to a table in our
> database. All our rules work as we expected and the system produces the
> correct results.
>
> However, the memory usage of the JVM steadily goes up when the system runs
> for extended periods of time until we start getting OutOfMemoryExceptions
> and the server has to be restarted. This is in spite of the fact that the
> fact count reported by
> the StatefulKnowledgeSession.getFactCount() stays reasonably stable,
> with around 30 000 facts (give or take) at any point in time.
>
> I have run the Eclipse Memory Analyzer tool (http://www.eclipse.org/mat/)
> against heap dumps from the JVM several times now, and every time it
> reports more and more instances
> of org.drools.common.ScheduledAgendaItem referenced from one instance of
> java.lang.Object[]
>
> To be concrete, since this morning the uptime is more than 112 hours in
> total, during which the system has processed little over 2 000 000 events
> from the network. It has 29 000 facts in the knowledge session, yet in the
> heap dump we see 829 632 instances of
> org.drools.common.ScheduledAgendaItem.
>
> What is the ScheduledAgendaItem for? Is there something wrong with my rules
> that causes this many instances to be held? Is there something I should do
> to release these instances or the Object[] holding on to them?
>
> Thanks,
> Werner Stoop
>