PQ62260: OUT OF MEMORY CONDITION WHEN WEBSPHERE APPLICATION SERVER R4.0.3IS UNDER HEAVY LOAD WITH SECURITY ENABLED | |||||||||||||||||||||||||||||||||||||
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APAR status Closed as program error. Error description Customer using a CustomRegistry and running a load test with 10 stress clients that do the following: - authenticate using a Trust Association & the custom registry - fetch a single JSP page - pause 10 seconds - leave the site. NO LOGOUT - repeat The clients use userids out of a possible population of about 10,000 userids. Thus, over a reasonable period of time, the Application Server will see 10,000 unique userids. The admin server, over a long period of time, logs out of memory errors. In this case, it took 4 hours.Local fix Problem summary **************************************************************** * USERS AFFECTED: All WebSphere Application Server users who * * have enabled security using LTPA * * authentication. * **************************************************************** * PROBLEM DESCRIPTION: Slow performance and high CPU usage * * during security cache cleaning cycles * * and possible OutOfMemoryExceptions. * **************************************************************** * RECOMMENDATION: * **************************************************************** Slow performance and high CPU usage during security cache cleaning cycles and possible OutOfMemoryExceptions. These issues are seen on servers with a large number of different users (12000 on the reported system) accessing the system within the security cache timeout period. The performance problem was a result of the cache cleaning algorithm which evaluated each cache entry as to whether or not it needed to remain in the cache. The out of memory condition was a result of the algorithms failure to remove cache entries.Problem conclusion The cache cleaning algorithm was changed to evaluate all cache entries inserted into the cache within a similar time period (one half the security cache timeout) at the same time. The new algorithm guarantees that the vast majority of entries will stay in the cache for the minimum of the security cache time out. There is now the potential for a small number of cache entries to be flushed from the cache early or for a cache miss to occur when there should have been a hit. This is negligible in comparison to the amount of time saved in cache cleaning, however.Temporary fix Comments
APAR is sysrouted FROM one or more of the following: APAR is sysrouted TO one or more of the following: PQ38019 Modules/Macros
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Document Information |
Product categories: Software > Application Servers >
Distributed Application & Web Servers > WebSphere Application
Server > General
Operating system(s):
Software version: 400
Software edition:
Reference #: PQ62260
IBM Group: Software Group
Modified date: Apr 30, 2003
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