PM91196: OUTOFMEMORYERROR CAUSED BY MEMORY LEAK IN CACHING THE WRAPPER FOR URIS

8.5.5.1: WebSphere Application Server V8.5.5 Fix Pack 1
8.5.5.2: WebSphere Application Server V8.5.5 Fix Pack 2
8.5.5.3: WebSphere Application Server V8.5.5 Fix Pack 3
8.5.5.4: WebSphere Application Server V8.5.5 Fix Pack 4
8.5.5.5: WebSphere Application Server V8.5.5 Fix Pack 5
8.5.5.6: WebSphere Application Server V8.5.5 Fix Pack 6
8.5.5.7: WebSphere Application Server V8.5.5 Fix Pack 7
8.5.5.8: WebSphere Application Server V8.5.5 Fix Pack 8
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
8.5.5.14: WebSphere Application Server V8.5.5 Fix Pack 14

APAR status

• Closed as program error.

Error description

• Caching the wrapper for the URI is a performance enhancement.
  It will save the server from repeatedly process and create the
  necessary resources when serving the same request/URI several
  times.
  However, when an application creates unique requests for the
  same static content, excess memory may be consumed.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:  All users of IBM WebSphere Application      *
  *                  Server Liberty Profile                      *
  ****************************************************************
  * PROBLEM DESCRIPTION: An OutOfMemoryError (OOM) can occur     *
  *                      when requesting static content.         *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  Under a very specific design, an application can cause the
  server to run out of memory when serving a lot of unique
  static content. The heapdump shows a large amount of memory is
  held by:
  com.ibm.ws.webcontainer.webapp.WebAppImpl
  com.ibm.wsspi.webcontainer.util.URIMapper
  com.ibm.wsspi.webcontainer.util.URIMatcher
  com.ibm.ws.util.ClauseNode
  com.ibm.ws.util.ClauseTable
  The memory is occupied by the caching of the URI of the static
  content.
  This is mainly for performance reason. When an application is
  designed such that every request for the same static content
  is unique, it consumes more memory to cache the requests.
  

Problem conclusion

• The WebContainer code was modified to accommodate those
  special applications by disabling static caching of the URI.
  
  A new WebContainer customer property needs to be set to enable
  the behavior provided by this APAR:
  
  com.ibm.ws.webcontainer.disableStaticMappingCache
  
  The following value can be specified for this property:
  
      * - disable static caching for all deployed applications
  
      A comma delimited list of specific applications that will
  have the disable static caching
  
  The following examples illustrate how to specify these two
  settings:
  
  com.ibm.ws.webcontainer.disableStaticMappingCache=*
  
  com.ibm.ws.webcontainer.disableStaticMappingCache=SpecialApp,Rar
  eApp
  
  Alternatively, a context parameter can be set in the web.xml
  to disable static caching for the application.
  
  <context-param>
    <param-name>
  com.ibm.ws.webcontainer.DISABLE_STATIC_MAPPING_CACHE</param-name
  >
    <param-value>true</param-value>
  </context-param>
  
  The fix for this APAR is currently targeted for inclusion in
  fix pack 8.5.5.1. Please refer to the Recommended Updates page
  for delivery information:
  http://www.ibm.com/support/docview.wss?rs=180&uid=swg27004980
  

Temporary fix

Comments

APAR Information

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

  PM84305

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

Fix information

• Fixed component name

  LIBERTY PROFILE

• Fixed component ID

  5724J0814

Applicable component levels

• R850 PSY

     UP