Hi,

did you use the standard GC or did you specify something like CMS as GC?

I've also used JProfiler to find out the memory leak reason. I found that when in heavy load all byte[] object will used 1.2G RAM and didn't

have a chance to be GCed, the OutOfMemoryError is throwed. while in low level load byte[] object could be GCed once in several seconds

This sounds like a JVM problem, so you may want to decrease the load or use CMS or something else for GC.

LG

Hey Weihua,

Yes, I would say so.You are logging in about 100 users per second (I gues per client) and then each user is changing his presence every second. If you install the load statistics plugin you will be able to see that the incoming queues are getting filled up a lot faster than the server can process each request. That is what is making the server run out of memory.

I would recommend increasing the delay between your requests and create a more realistic scenario. Users do not change their presence every second or every 5 seconds. Since you have about 19 contacts in your roster you are basically flooding your network. Lets say that you have 10K logged users already. In a second they will send 10K presences that in turn will proximately imply 190K outgoing packets. As a first attempt, change the presence change to 5 minutes and see what the load statistics plugin show.

Regards,

  -- Gato

Hey liqingfeng,

I don't really the numbers from the top of my head and I do not have the scripts now at hand. But I do remember that the activity per user was based on average load (e.g change presence every 5-10 minutes, chat at a human spead, ~20 contacts per roster, etc.). Since XMPP ends up being a network activity you have to consider your network speed too. Client should read fast or otherwise the TCP layer will make the sender go slower thus filling up the outgoing queue. As I said, use the load stats plugin to see what is going on inside the server and easily identify what is causing possible out of memory problems.

  -- Gato