PQ72570: CLASSCASTEXCEPTIONS SEEN IN MEM TO MEM MODE WITH LOW PERFORMANCEOPTION SELECTED ON THE SESSION MANAGER SERVICE | |||||||||||||||||||||||||||||||||||||||||||||||
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![]() APAR status Closed as program error. Error description I am using trade3 benchmark application. I do not know what attributes the application writes to the session object. But the sequence is simpler. You do not need to restart a server, and an error occurs from the start. 1. Install trade3 to a cluster including two servers. 2. In the same way as your mail, enable mem to mem in both client and server mode on the both server 3. Set tuning level LOW in custom tuning parameter of distributed environment setting. 3. Send several Get requests to http://xxx/trade/scenario 4. There is an error statement in SystemOut.log http://trade/scenario internally calls other servlets (login, quote, portfolio, logout .. ) randomly according to predefined probability distribution. So it keeps current states ( user id ) in a session. If it works correctly, it travels several servlets with the same user id for a while. But if it cannot retrieve a user id from a session, it starts with a new user id. When I select Byte serialization, http://trade/scenario always start with a new user id. No error is displayed in a web page, but an error statement is output in SystemOut.log Session affinity is enabled by HTTP server plug-in. So all the requests are sent to the same application server. I cannot understand why such an error occurs. But I am sure that the same application works correctly with Object serialization, DB persistence, and in-memory session management. Operating system is RedHat Linux V7.3.Local fix Problem summary **************************************************************** * USERS AFFECTED: WebSphere Application Server -- Session * * Manager Users * **************************************************************** * PROBLEM DESCRIPTION: ClassCastExceptions seen in Mem to * * Mem Mode with Low Performance option * * selected on the Session Manager Service * **************************************************************** * RECOMMENDATION: * **************************************************************** The Session Manager has various options which offer different performance levels. In the Mem to Mem Mode, if the Low Performance option was selected, on the second request for the same HttpSession a ClassCastException was being thrown.Problem conclusion This problem has been fixed and the ClassCastExceptions are no longer thrown by the Session Manager when Low Performance is enabled.Temporary fix Comments
APAR is sysrouted FROM one or more of the following: APAR is sysrouted TO one or more of the following: Modules/Macros
Publications Referenced
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Product categories: Software > Application Servers >
Distributed Application & Web Servers > WebSphere Application
Server > General
Operating system(s):
Software version: 00I
Software edition:
Reference #: PQ72570
IBM Group: Software Group
Modified date: Apr 28, 2003
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