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IBM Tivoli Identity Manager Performance Tuning Guide
5 IBM DB2
Tuning IBM DB2 to run with the IBM Tivoli Identity Manager product involves adjusting the buffer pools,
modifying the number of connections, modifying internal database values, adding table space, adjusting
logs, indexing, and running runstats.
The tuning JCL provided applies to the z/OS 1.6 LDAP server. The z/OS 1.8 LDAP server was not
available at the time this document was prepared.
5.1 APARs
Two ODBC APARs have been linked to poor LDAP performance on z/OS. It is recommended that these
APARs be installed on the system:
• PK21695 – Mutex lock contention
• PK17652 – High CLI CPU utilization
5.2 Buffer pools
Tuning the IBM DB2 buffer pools has shown to decrease deadlocks and improve overall performance.
IBM Tivoli Identity Manager includes three JCL scripts to tune the IBM DB2 buffer pools based on which
database is being tuned and how WebSphere Application Server is set up.
Determining the values
# JCL location Description
1 hlg.SAERSAMP(AERTNDBC) Tune ITIM database when using a WAS cluster
2 hlg.SAERSAMP(AERTNDBS) Tune ITIM database when using a single WAS server
3 hlg.SAERSAMP(AERTNLDP) Tune LDAP database
Identify which JCL script is needed to tune your Tivoli Identity Manager database (either 1 or 2). JCL
script 3 is used for the LDAP database for both single and clustered WebSphere configurations.
Setting the values
1) Edit the JCL to conform to your installation’s standards.
2) Update DB2 schema names, such as the database name, to match your environment.
3) Submit the JCL for execution.
5.3 Idle thread timeout
DB2 continually checks for idle threads to cancel. Sometimes during SQL queries that return large
amounts of data, if there is a delay between the sending of one DRDA query block and another, an abend
04E reason code 00D3003B, may occur, indicating that the idle thread timeout was exceeded. Increase
the idle thread timeout to avoid this error.
Determining the values
idle_thread_timeout – Total time in seconds before an idle thread will timeout. Default value: 120.
Recommended value: 7200. This value is in the DB2
DSNTIJUZ customization job, located on the
IDTHTOIN operand for the DSN6FAC macro