PI47875: EXCESSIVE MEMORY USE WHEN AN APPLICATION USES MANY CLASSLOADERS.

8.5.5.9: WebSphere Application Server V8.5.5 Fix Pack 9
8.5.5.10: WebSphere Application Server V8.5.5 Fix Pack 10
8.5.5.11: WebSphere Application Server V8.5.5 Fix Pack 11
8.5.5.12: WebSphere Application Server V8.5.5 Fix Pack 12
8.5.5.13: WebSphere Application Server V8.5.5 Fix Pack 13
8.5.5.14: WebSphere Application Server V8.5.5 Fix Pack 14
8.5.5.15: WebSphere Application Server V8.5.5 Fix Pack 15
8.5.5.17: WebSphere Application Server V8.5.5 Fix Pack 17
8.5.5.20: WebSphere Application Server V8.5.5.20
8.5.5.18: WebSphere Application Server V8.5.5 Fix Pack 18
8.5.5.19: WebSphere Application Server V8.5.5 Fix Pack 19
8.5.5.16: WebSphere Application Server V8.5.5 Fix Pack 16
8.5.5.21: WebSphere Application Server V8.5.5.21

APAR status

• Closed as program error.

Error description

• When an application uses thousands of classloaders, a reference
  to these might be held by the
  com.ibm.ws.naming.jcache.CacheManager class, resulting in
  excessive memory use.
  

Local fix

• na
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:  All users of IBM WebSphere Application      *
  *                  Server                                      *
  ****************************************************************
  * PROBLEM DESCRIPTION: Excessive memory use by applications    *
  *                      using large numbers of classloaders     *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  A heapdump will show a large number of classloader references
  held by com.ibm.ws.naming.jcache.CacheManager.  None of these
  classloaders or the classes they have loaded can be garbage
  collected.
  

Problem conclusion

• The size of the naming cache is unbounded by default. An
  existing JVM property,
  com.ibm.websphere.naming.jndicache.maxcachelife can be set to
  limit cache lifetime, but the CacheManager was continuing to
  hold references to classloaders even though cached lookup
  results had been cleared.
  
  The code is revised so that when maxcachelife is set,
  classloader references will be periodically cleared.
  
  The fix for this APAR is currently targeted for inclusion in
  fix pack 8.5.5.9.  Please refer to the Recommended Updates
  page for delivery information:
  http://www.ibm.com/support/docview.wss?rs=180&uid=swg27004980
  

Temporary fix

• Set the JVM property
  com.ibm.websphere.naming.jndicache.cacheobject=none to disable
  caching.  Note that this might degrade naming lookup
  performance.
  

Comments

APAR Information

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

• APAR is sysrouted TO one or more of the following:

Fix information

• Fixed component name

  WEBS APP SERV N

• Fixed component ID

  5724H8800

Applicable component levels

• R850 PSY

     UP