These are the detailed results from Michigan's stress-testing of the chat2 tool. The last six weeks have seen some exciting developments from Charles Hedrick and Dave Haines in regards to this tool (see sak-13274). We have seen some production performance issues specifically related to the chat tool. The recent performance upgrades go a long way towards addressing these issues. The current sakai 2.4 chat2 tool appears to execute SQL in the database long after user's sessions have ended. The current build is also very CPU intensive on the database throughout a chat session. The recent patch alleviates the first problem entirely, and diminishes database CPU activity a great deal.
One of the interesting data points from the previous build was the number of database SQL executions that occurred after the test was finished. Here is the graph of execution count for the current 2.4 production build, and here is the graph for the patched build. Notice the gradual taper off of database executions in the production build, whereas database activity drops off immediately after the test ends in the patched build. This is evidence that persistent beans are being destroyed as they should, per Charles' comments in the jira. Also, the patched build is less CPU intensive. Here is the DB CPU graph for the production build, and here it is for the patched build.
Any institutions experiencing performance problems with the current Sakai 2.4 chat2 tool or thinking of implementing it for the first time should consider the sak-13274 patch.
Please contact me with any questions or concerns.