PM13652: STACK OVERFLOW IN VARIOUS FIL OPTIMIZERS

APAR status

• Closed as program error.

Error description

• StackOverflowExceptions may occur in various FIL optimizers.
  In mixed/interpreted mode, StackFrameAnalyzer may trigger a
  stack overflow.  In compiled mode, XDMSequenceOptimizer may
  trigger a stack overflow.
  
  The errors often occur with very large stylesheets and
  are more frequent on certain platforms (PPC) and in the
  context of running many transformations, as JIT compilation can
  greatly  increase stack usage.
  
  Stack usage should be reduced as much as possible in these
  optimizers in order to reduce the likelihood of stack
  overflow.  A work-around is to increase the JVMs stack size,
  but ideally the optimizers should use less stack than the
  default amount allocated.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:  Users of IBM WebSphere Application Server   *
  *                  7.0 with Feature Pack for XML 1.0.0.5 or    *
  *                  earlier                                     *
  ****************************************************************
  * PROBLEM DESCRIPTION: Very large stylesheets or queries may   *
  *                      cause stack overflow                    *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  Very large stylesheets or queries may cause stack overflow,
  especially when running on PPC platforms or in the context of
  running many transformations or queries, as JIT compilation can
  greatly increase stack usage.  This causes preparation
  (compiled or interpreted) of the stylesheet or query to fail.
  

Problem conclusion

• Optimizer algorithms that were previously fully recursive have
  been modified to use iteration when possible to limit stack
  usage.  This reduces the likelihood of stack overflow.
  
  This APAR is currently targeted for inclusion in the Feature
  Pack for XML 1.0.0.7.  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:

• 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