PM05607: LOOP IN DYNACACHE AFTER 404 RESPONSE IS CACHED UNDER CERTAIN CONDITIONS.

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• When servlet caching is enabled and a cachespec.xml that uses
  the SimpleFileServlet technique to cache static files is
  available in the web module:
    <cache-entry>
        <class>static</class>
          <name>com.ibm.ws.webcontainer.servlet.
                          SimpleFileServlet.class</name>
        <cache-id>
           <component id="" type="pathinfo">
              <required>true</required>
           </component>
           <component id="If-Modified-Since" type="header">
              <required>false</required>
           </component>
           <timeout>1800</timeout>
        </cache-id>
    </cache-entry>
  
  Requesting a nonexistent resource causes HTTP 404 error code
  to be cached. On a subsequent request for the same resource,
  the request enters an infinite loop and this causes a
  StackOverflowError.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:  All users of IBM WebSphere Application      *
  *                  Server V7.0 using servlet caching with      *
  *                  content with an error HTTP response code.
  ****************************************************************
  * PROBLEM DESCRIPTION: An application may not expect content   *
  *                      to be cached on a cache miss with an    *
  *                      error HTTP response status code.        *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  Dynacache does not look at the HTTP response code to determine
  an error occurred and caches the cache miss.  When a
  subsequent cache hit occurs the cached output is returned with
  the error.
  

Problem conclusion

• A new JVM custom property is being introduced,
  com.ibm.ws.cache.CacheConfig.filteredStatusCodes.  This JVM
  custom property contains a space delimited list of HTTP
  response error codes.  Dynacache will not cache the content on
  a cache miss if the status code is one of the error codes in
  the list.
  
  APAR PM05607 requires changes to documentation.
  
  NOTE: Periodically, we refresh the documentation on our
  Web site, so the changes might have been made before you
  read this text. To access the latest on-line
  documentation, go to the product library page at:
  
  http://www.ibm.com/software/webservers/appserv/library
  
  Changes to the WebSphere Application Server Version 7.0
  Information Center will be made available in
  October, 2010.
  
  The topic "Java virtual machine custom properties" will
  be updated to include the following description of the
  com.ibm.ws.cache.CacheConfig.filteredStatusCodes custom
  property:
  
  com.ibm.ws.cache.CacheConfig.filteredStatusCodes
  
  Use the property to indicate error situations in which
  you do not want the dynamic cache service to cache the
  output of the servlet.
  
  The value specified for this property is a space
  delimited list of HTTP response error codes. If the status
  code returned from a cache miss matches one of the listed
  response error codes, the dynamic cache service does not
  cache output of the servlet.
  
  APAR PM95607 is currently targeted for inclusion in Service
  Level (Fix Pack) 7.0.0.13 of WebSphere Application Server V7.0.
  
  Please refer to URL:
  //www.ibm.com/support/docview.wss?rs=404&uid=swg27006970
  for Fix Pack availability.
  

Temporary fix

Comments

APAR Information

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

  PM03636

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

Fix information

• Fixed component name

  WEBSPHERE FOR Z

• Fixed component ID

  5655I3500

Applicable component levels

• R700 PSY UK61114

     UP10/10/21 P F010

Fix is available

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