The purpose of this page is to enable you to resolve errors which occur when the number of browser sessions shoots up suddenly, causing PI to become unstable.
In PI, sometimes due to misconfiguration, a very large number of browser sessions are created unexpectedly and the PI system becomes unstable leading to situations where you see GRMG Heartbeat errors, ICM overload and access to SLD fails. The main causes and how to prevent it will be discussed in this page.
Browser Sessions Overload
A browser session is created when a request is sent by the application. Sometimes, a large number of requests may cause a large number of browser sessions to be opened. An overload of browser sessions can cause several problems in the system, for example, an ICM overload with entries like:-
[Thr 11502779] *** WARNING => SfIFindShmWebSession
[Thr 11502779] *** ERROR => server overload: no more sessions available
You can see the number of browser sessions currently in use as shown in this screenshot.
Controlling the Number of Browser Sessions
There are two ways to keep in check the number of browser sessions open.
Decrease the sessions timeout value. In this case http sessions will expire in shorter interval. It is possible to set and modify a session timeout period for a particular web-module as an application context-wide setting. In order to set this parameter, you need to follow this path :- http://<host>:port/nwa -> Configuration Management -> Infrastructure -> Application Modules
Select the relevant module in the Modules List screen area and then select Context in the Web Module Details screen area and enter an appropriate integer number for the Session Timeout parameter.
Enable stateful communication for the web service. In this case the session reuse will decrease the number of http sessions. A stateful Web service preserves its state when multiple calls are made from the same web service client, in the same HTTP session. The default implementation of a web service is stateless. Stateful communication is implemented by setting it so in the implementation bean. Currently, the only mechanism to handle stateful sessions is HTTP cookies.
SAP help: Configuring Additional Settings
Related SAP Notes/KBAs