Unexpected TaskInvalid exception thrown when using scheduler management operations
 Technote (troubleshooting)
 
Problem(Abstract)
The IBM® WebSphere® Application Server scheduler cancel, purge, suspend and resume API methods or MBean operations may throw an incorrect TaskInvalid exception if the task is running or is about to run.
 
Cause
There is a small window in which a task may return a com.ibm.websphere.scheduler.TaskInvalid Exception incorrectly. This is caused by some database platforms not locking a row using READ_COMMITTED transaction isolation unless the data in the row changes.

The iSeries® DB2® database has the following behaviors which increase the likelihood of this error:

  1. iSeries may ignore the READ_COMMITTED transaction isolation setting on the connection and may instead use READ_UNCOMMITTED.

  2. iSeries prevents row locks when SELECT... FOR UPDATE is used with READ_COMMITTED transaction isolation where the result set is not updated. Because the scheduler uses this mechanism to lock the row prior to updating, This may result in the unexpected TaskInvalid exception.
 
Resolving the problem
1. Apply iSeries fixes:
  • V5R2M0 PTF - MF34388
  • V5R3M0 PTF - MF34383
2. Apply an interim fix or service pack that contains scheduler APAR PK03786. This fix is available in the following service releases:
  • Scheduler cumulative interim fix 1 for WebSphere Enterprise 5.0.2.6
  • WebSphere Business Integration Server Foundation version 5.1.1.2
  • WebSphere Application Server 6.0.1.2 (All editions)
  • WebSphere Application Server 6.0.2 (All editions)

Workaround:
Catch the TaskInvalid exception and submit the cancel, purge, suspend or resume request again.
 
 
Cross Reference information
Segment Product Component Platform Version Edition
Application Servers Runtimes for Java Technology Java SDK
 
 


Document Information


Product categories: Software > Application Servers > Distributed Application & Web Servers > WebSphere Application Server > Scheduler
Operating system(s): AIX
Software version: 6.0
Software edition:
Reference #: 1209263
IBM Group: Software Group
Modified date: Oct 2, 2007