PI15529: Hung thread in CacheNodeSequence due to frequent array expansion

APAR status

• Closed as program error.

Error description

• Hung thread, CPU issue:
  
  ThreadMonitor W WSVR0605W: Thread "WebContainer : 0" (0000005b)
  has been active for 694749 milliseconds and may be hung. There
  is/are 1 thread(s) in total in the server that may be hung.
  
  atcom.ibm.xml.xci.dp.cache.dom.CacheNodeSequence.appendSequence
  (CacheNodeSequence.java:678)
  
  atcom.ibm.xml.xci.dp.cache.dom.CacheNodeSequence.sequenceConcat
  (CacheNodeSequence.java:403)
  
  atcom.ibm.xltxe.rnm1.xtq.xslt.runtime.v2.BasisLibrary2.
  xpathStep(BasisLibrary2.java:4907)
  

Local fix

• n/a
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:  All IBM WebSphere Application Server        *
  *                  Feature Pack for XML users                  *
  ****************************************************************
  * PROBLEM DESCRIPTION: Hung thread in CacheNodeSequence due to *
  *                      frequent array expansion                *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  The algorithm to expand the array in
  com.ibm.xml.xci.dp.cache.dom.CacheNodeSequence consumes a lot
  of resources when iterating over an extremely large Cursor set
  that contains thousands of nodes.
  The following hung thread message could be seen :
  Thread "WebContainer : 5" (00000dab) has been active for
  669268 milliseconds and may be hung.  There is/are 1 thread(s)
  in total in the server that may be hung.
  at
  com.ibm.xml.xci.dp.cache.dom.CacheNodeSequence.appendSequence(Ca
  cheNodeSequence.java:678)
  at
  com.ibm.xml.xci.dp.cache.dom.CacheNodeSequence.sequenceConcat(Ca
  cheNodeSequence.java:403)
  at
  com.ibm.xltxe.rnm1.xtq.xslt.runtime.v2.BasisLibrary2.xpathStep(B
  asisLibrary2.java:4907)
  .....
  .....
  

Problem conclusion

• The new algorithm expands the array more efficiently and does
  not exhaust the system, which prevents the thread from being
  hung.
  
  The fix for this APAR is currently targeted for inclusion in
  IBM WebSphere Application Server Feature Pack for XML
  1.0.0.17. 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:

  PI15317

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

Fix information

• Fixed component name

  XML FEATUREPACK

• Fixed component ID

  5724J0856

Applicable component levels

• R700 PSY

     UP