[cle-release-team] Sakai 2.9 Load Testing Results

[Beth Kirschner]

The University of Michigan has been load testing the Sakai 2.9 build under various scenarios, and have seen several concerning increases in the underlying infrastructure:

1) At login, the database usage increased by a factor of 3x (we have a fabulous database server, but still noticed an increase from 5% cpu usage to 15% usage). For those who don't have as powerful of a database server, this could be significant. Changing how the neoportal constructs the tool lists for each site from querying tools for all sites to a 'just-in-time' query for the requested site brought the database cpu usage down to 5%. We plan on checking in these changes to trunk.
	https://jira.sakaiproject.org/browse/SAK-22907

2) At login, the appserver cpu usage also increased by a significant factor (from 23% to 35%). We are still looking for the root cause of this increase. We also compared running the 2.9 release on a Tomcat 5.5 versus Tomcat 7 server (just for comparison), and found that this brought the increased usage down to 30%. We're looking for both the cause of the appserver cpu increase as well as looking for tuning options for Tomcat 7. Ideas are welcome, and we'll share what we find.

Thanks,
- Beth