Resolution:
Description:
============
Applications using XML parsing may experience performance degradation with excessive excps against the z/OS execution library.

Environment:
============
This issue affects z/OS TIBCO Object Service Broker environments where
  * application rule parsing of XML documents occurs -or-
  * use of facilities which indirectly use XML parsing such as:
     o TIBCO Object Service Broker Object Integration Gateway or
     o TIBCO Object Service Broker UI
are used.

Usually heavily loaded systems are not as affected as moderate to low usage systems since the z/OS XML module usage count in highly loaded systems is less likely to reach zero.

Symptoms:
=========
* Excessive excp (I/O) counts against the XML execution load library usually identified by the jobstep //STEPLIB DD statement
* slower performance
* high CPU usage

Cause:
======
The IBM Xerces XML parsing routines used by TIBCO Object Service Broker are quite large but reentrant. The XML parsing modules are loaded when first referenced. Unfortunately, if the use count reaches zero, the modules may be released by z/OS even though they may be required shortly for further processing by another user session or transaction. If the module has been released, TIBCO Object Service Broker will reference the module again and z/OS will have to reload the module in question. Continually reloading these modules will cause excessive I/O to the XML library, resulting in higher CPU usage and processing delays.

Resolution:
=========
Customers using XML services should acquire the maintenance for their level of TIBCO Object Service Broker (OSB) as follows:

5.2           AP13527 Preload XMLPARSER routines
5.0 HOTFIX 13 AP13450 Preload XMLPARSER routines

Customers running TIBCO Object Service Broker for z/OS 5.2.0 should open a service request and request notification when AP13527 is available via a hotfix.

Some reports have indicated that by applying the fixes, excps to the STEPLIB have been reduced by an order of magnitude resulting in less CPU time and faster processing.


References:
==========
5.0 LBN1-B9HUKO  Hotfix 13 for TIBCO(R) Object Service Broker for z/OS 5.0.0 is now available.