Drools Execution Server memory leak?

Mike Reynolds

2011-06-28 18:37:19 UTC

Using: 5.2.0.Final of drools camel server , JSON api, and a Stateless Session
We are making JSON calls to the camel (execution) server. Our
end-to-end unit tests pass. Our load tests, however, show that memory
is never reclaimed after each call to the rules engine. After parsing
through a heap dump, we see the following path taking up over 800 meg of
memory:
(kagent) KnowledgeAgentImpl$ChangeSetNotificationDetector

(kbase) KnowledgeAgentImpl

(ruleBase) KnowledgeBaseImpl

(eventSupport) ReteooRuleBase

(listeners) RuleBaseEventSupport

(array) CopyOnWriteArrayList

ReteooWorkingMemory (around 864K of these)

The rule base is very small and simple - this is only a problem during a load test (or over the course of a weeks worth of calls). We make the following call 10K times:
{
"batch-execution": {
"lookup": "ksession1",
"commands": [
{
"insert": {
"out-identifier": "tc_1",
"object": {.....}
}}]}}
The knowledge-services.xml configures :
- kagent id="agent1" kbase="kbase1" new-instance="true"
- ksession id="ksession1" type="stateless" kbase="kbase1" node="node1"

The rules just update the inserted "timecard" fact.

Because I'm using a stateless session, I don't think I need to
dispose of the agent...and I don't think there is a way to call dispose
using the json/Execution Command api.

We are calling the camel (execution) server from a non-java
environment to process employee timecards entries and evaluate for
overtime calculations.

Thanks!
Mike