If your installation uses typical
DB2 defaults for U-lock management and lock size, certain WebSphere
Application Server applications that use container-managed Enterprise
beans (CMP beans) might encounter deadlocks. The likelihood of encountering
deadlocks is entirely dependent on the design and execution pattern
of the applications. The potential for deadlocks increases with the
number and frequency of applications driving concurrent transactions
that update the same areas of the DB2 database. If, given the workload
for your applications, the potential for deadlocks is high, consider
using the following DB2 settings:
RRULOCK(YES)
LOCKSIZE(ROW)
For additional details, see the information about settings for the
internal resource lock manager (IRLM) in your DB2 Installation Guide.
Your applications might qualify for the optimistic approach
to concurrency control management. To determine whether your applications
can use optimistic concurrency control, see the topic about concurrency
control in the z/OS view of the WebSphere Application Server Information
Center.