PM47425: POOR PERFORMANCE RESULTS FROM USING COMPUTED COMMENT CONSTRUCTOR S IN XQUERY

APAR status

• Closed as program error.

Error description

• The performance for an XQuery expression that evaluates many
  computed comment constructors expressions is poor in
  comparison to an expression that evaluates an equal number of
  text node constructors.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:  All IBM WebSphere Application Server        *
  *                  Feature                                     *
  *                  Pack for XML users                          *
  ****************************************************************
  * PROBLEM DESCRIPTION: XQuery expressions that construct       *
  *                      many comment nodes using computed       *
  *                      comment constructors exhibit poor       *
  *                      performance.                            *
  ****************************************************************
  * RECOMMENDATION:  Install a fix pack that contains this       *
  *                  APAR.                                       *
  ****************************************************************
  The XQuery Recommendation requires that an error be reported
  if the value supplied in a computed comment constructor
  contains two adjacent hyphens or ends with a hyphen.  The
  processor is checking this by applying a regular expression to
  the value of the comment constructor.  The regular expression
  implementation used in this case is not very efficient.
  

Problem conclusion

• The problem was resolved by replacing the use of  a regular
  expression to check for adjacent hyphens in the value of
  computed comment constructor or to check whether the value
  ends with a hyphen with a simple loop that performs the same
  two tests.
  
  The fix for this APAR is currently targeted for inclusion in
  fix pack 1.0.0.11.  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:

  PM47616

Fix information

• Fixed component name

  XML FEATUREPACK

• Fixed component ID

  5724J0856

Applicable component levels

• R700 PSY

     UP