[rules-users] Drools 5 Memory Issues

[Mark Proctor]

On 27/12/2011 21:16, drools.user wrote:
> We are planning on moving from Drools 3.0.5 to Drools 5.2.0. In Load Testing
> of Drools 5.2, we faced some issues:
>
> 1. KnowledgeBaseImpl Object in Drools 5 is almost 50% bigger than
> ReteooRuleBase Object of Drools 3.
> 2. The server heap memory usage keeps on increasing during Load Testing to
> finally give OutOfMemory error and crash.
Try 5.4 beta 1 - there have been a lot of fixes of listeners not being 
removed, some related to memory leaks over 5.2, 5.3 and 5.4.
> We are using StatefulKnowledgeSession and calling dispose() after
> fireAllRules().
>
> So, the questions we have are:
>
> 1. Looking at the heap snapshot, we noticed>  300,000 Objects for some of
> Drools Classes (e.g. org.drools.reteoo.LeftTupleImpl) occupying>  25MB in
> heap memory. Is that normal?
>
> 2. Is there any Memory Leak issues with Drools 5?
>
> 3. What is the advantage of using KnowledgeBase vs RuleBase? Is it fine to
> use RuleBase in Drools 5?
KnowledgeBase is just a wrapper for the legacy rulebase impl. The 
downside is that rulebase will be removed soon - you need to use classes 
in the -api to ensure longer term compatability.
>
> 4. We are using Drools 5.2. Has anything changed significantly in Drools
> 5.3? Will moving to that help in our memory issues?
See above about listeners not being removed.
>
> Thanks
>
>
>
>
> --
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