eG Help

The Manager element on the Tomcat server represents the session manager that will be used to create and maintain HTTP sessions as requested by the associated web application. A session state is maintained for a period, typically starting with user interactios and ending with last interaction.

Besides memory management, manager also looks into various aspects including CPU usage, network load that large sessions introduce. The scalability and performance of any web based application depends upon how well HTTP sessions are transmitted and managed over network.

An application must guarantee that a user's session state is properly maintained in order to exhibit correct behavior for that user. The TomcatAppTest closely monitors the state of sessions to the Tomcat server.

Measurement	Description	Measurement Unit	Interpretation
Active_sessions	Indicates the sessions that are currently active	Number	A high value for this measure is indicative of heavy load on the Tomcat server.
Max_sessions	Indicates the high watermark for sessions on the Tomcat server	Number
Expired_sessions	Indicates the number of sessions that expired since the last measurement period	Number	A large number of expired sessions could hint at the need to reset the TIMEOUT period for sessions on the Tomcat server.
Rejected_sessions	Indicates the number of sessions that were rejected since the last measurement period	Number	It is imperative to check if there is any loss of session state happening due to network congestion. Therefore, if the value of this measure is unusually high, the reasons behind the unusual occurrence would have to be investigated.