The server collects PMI data, such as servlet response time and data connection pool usage, in memory. The data points are then retrieved using a Web client, a Java client, or a Java Management Extensions (JMX) client. The PMI data collected is representative of the entire set of servers, rather than individual servant regions, so the captured data does not display statistics for individual servers. Therefore, PMI data will be less useful in diagnosing heap problems, connection pool problems, or similar issues that exist within a specific servant. WebSphere Application Server contains Tivoli Performance Viewer, a Java client which displays and monitors performance data. See the Monitoring performance with Tivoli Performance Viewer (formerly Resource Analyzer), and Developing your own monitoring applications topics for more information on monitoring tools.