PH20311: PLUG-IN DOES NOT READ ENTIRE RESPONSE FROM THE SOCKET WHEN ESI IS ENABLED AND RESPONSE SHOWS DATA IS NOT MODIFIED

8.5.5.17: WebSphere Application Server V8.5.5 Fix Pack 17
9.0.5.3: WebSphere Application Server traditional Version 9.0.5 Fix Pack 3

APAR status

• Closed as program error.

Error description

• Plug-in does not read the entire response from the socket when
  ESI is enabled and the response indicates that the data is
  not modified.
  
  Problem reported on Plug-in v9.0.5 and 8.5.5.x
  

Local fix

• Disable ESI cache in the plugin-cfg.xml file so that large
  responses can be cached.
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:  IBM WebSphere Application Server web        *
  *                  server plugin users                         *
  ****************************************************************
  * PROBLEM DESCRIPTION: If ESI caching is enabled on plugin,    *
  *                      servers could be incorrectly marked     *
  *                      down                                    *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  When ESI is enabled, if a request includes an "If-Modified"
  header and the response indicates that the data has not been
  modified, then plugin may not read the entire response. Data
  left unread on the socket may then be read on the next request
  using the socket to the application server. This lingering
  data would not have the expected format so the server would be
  marked down due to invalid format.
  

Problem conclusion

• Corrected the issue to close the socket under these conditions
  to prevent unread data from lingering on the socket.
  
  The fix for this APAR is targeted for inclusion in fix pack
  8.5.5.17 and 9.0.5.3.  For more information, see 'Recommended
  Updates for WebSphere Application Server':
  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:

• 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

• R900 PSY

     UP