we are tuning our GC and we observed that after sometime, GC times goes up and CPU but what i have seen is number of passing transactions also increased. But we are sending the same load. Do you know why this would increase? i don't see number purepaths increasing at that time.
Answer by Andreas G. ·
The number of passing transactions is the number of PurePaths that pass through the Application Server. Now - if this is an AppServer that is not a frontend server (Servlet, ...) but a service tier (web services, message handler, ...) it is possible that you see more passing transactions if the PurePaths that come in on the frontend make more web service calls to these agents.
What you should do is look at the activity on this agent. Focus on the interface it provides to the application, e.g: web service calls and look at this number.
Looking at the chart above definitely means that there is more traffic coming in.
Another explanation would be that - until that point where you see "lower load" - somewhere these requests queue up, e.g: web server. And for whatever reason the web server is then releasing these calls to the appserver
Explanation 3 would be that you have somebody else adding load to the system, maybe not your load test but another test that is running?
hope this helps