I am currently running version 5.1.0M2.  I have 18 different binary rulesets [packages] that are stored on the local filesystem.  The rulesets range in size from 4K to 131Mb.

When my application starts I load each ruleset into a knowledgeAgent and store the knowledgeAgent into a hashmap which is stored in memory.   They are loaded using the following xml:

<?xml version=\"1.0\" encoding=\"UTF-8\"?>

<change-set xmlns='http://drools.org/drools-5.0/change-set' xmlns:xs='http://www.w3.org/2001/XMLSchema-instance' xs:schemaLocation='http://drools.org/drools-5.0/change-set.xsd'>

<add>

<resource source='file://PATH_TO_BINARY' type='PKG' />

</add>

</change-set>

The knowledgeAgentConfiguration is setup as:

drools.agent.scanDirectories = false

drools.agent.newInstance = false

drools.agent.scanResources = false

drools.agent.monitorChangeEvents = false

After the all the agents are loaded and stored in the hashmap the total memory used in the app is 6.2GB. 

Once the application is running, if a business user needs to update a set of rules there is a process in place to refresh all the knowledgeAgents with new rulesets.  In a new thread. the code clears the hashmap, sets the hashmap to null, calls for garbage collection to occur, and it then constructs a new hashmap and loads all the rules as it does at application startup.

The knowledge agent is logging the following when the ruleset is loaded:

KnowledgeAgent applying ChangeSet

KnowledgeAgent performing an incremental build of the ChangeSet

KnowledgeAgent incremental build of KnowledgeBase finished and in use

It takes a large amount of time to do this process [double to triple the time of application startup]. After this occurs the memory used by the app increases [to nearly double the original size 12.2GB] and the CPU is maxed out.  After some time the CPU usage drops and the app is usable again but the memory never decreases.  If a business user refreshes the rules again, the memory increases again and the CPU is maxed out and the app becomes unresponsive because the memory is completely maxed out.

There is obviously a memory leak somewhere and a large one at that.  Is this the proper way to be caching KnowledgeAgents into memory so the rulessets don’t need to be re-loaded everytime a knowledgeAgent is run?  Is my problem the use of the hashmap?  Do I need to remove the original knowledgeAgents that were in the hashmap?

Thanks for any help.