Hello,

We've today updates to Drools 7.15 and as discussed with DROOLS-3228 we changed our code from calling StatefulKnowledgeSessionImpl.reset ourselves to KieSessionsPool. However we then recognized that our application quickly became slower and slower over time (roughly after a few minutes of uptime, or a couple of hundred session create/dispose cycles).

I haven't yet found the reason what is causing the slow down. However I think there is a difference in how we reset our sessions before session pools and how session pools do it. Perhaps that is a lead.

What we did

1. Create a session
2. Use the session
3. Dispose and reset the session and go back to 2 for the next facts

What happens with session pools

1. Create a session
2. Use the session
3. Skip dispose (because of pool != null in the dispose method), reset the session and go back to 2 for the next facts

So the difference seems to be that with session pools the session doesn't get disposed before reset it called. If I do the same without session pools then I also see the same slow down. So it seems that something is left behind and causes a slow down. The results however seem to be correct, so the right consequences appear to be triggered.

An example on how we use the session pool can be found here: https://github.com/liebharc/JavaRules/blob/master/src/main/java/com/github/liebharc/JavaRules/StatefulReusingDroolsEngine.java

Thanks once more for your help.