PQ38019: OUT OF MEMORY CONDITION WHEN WAS IS UNDER HEAVY LOAD WITH SECURITY ENABLED

A fix is available
WebSphere Application Server Version 3.5 Fix Pack 7 (3.5.7)

APAR

APAR status
Closed with unknown close code.

Error description
Customer using a CustomRegistry and running a load test with 100
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, WAS 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.
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- repeatThe clients use userids out of a possible population of about10,000 userids. Thus, over a reasonable period of time, WAS willsee 10,000 unique userids.The admin server, over a long period of time, logs out of memoryerrors. 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 information
APAR numberPQ38019
Reported component nameWEBSPHERE AE SO
Reported component ID5648C8402
Reported release350
StatusCLOSED
PENoPE
HIPERNoHIPER
Submitted date2003-03-03
Closed date2003-03-03
Last modified date2003-03-17

APAR is sysrouted FROM one or more of the following:
PQ62260

APAR is sysrouted TO one or more of the following:APAR is sysrouted FROM one or more of the following:PQ62260


Modules/Macros
SECURITY
APAR is sysrouted TO one or more of the following:Modules/Macros

Fix information
Fixed component nameWEBSPHERE AE SO
Fixed component ID5648C8402

Applicable component levels
R400 PSYUP











Document Information

Product categories: Software, Application Servers, Distributed Application & Web Servers, WebSphere Application Server, General
Software version: 350
Reference #: PQ38019
IBM Group: Software Group
Modified date: 2003-03-17