CICS Monitoring

CICS monitoring collects data about every transaction while it runs. This data is used for performance tuning, capacity planning, and charging users for the resources they use.

CICS Monitoring Facility (CMF)

• CMF is the built-in CICS component that records monitoring data. It writes records to SMF, usually SMF record type 110.
• Monitoring is controlled by SIT parameters and can be changed live with CEMT SET MONITOR.
• Keep monitoring on in production. The overhead is small and the data is very useful when problems happen.

Monitoring classes

• Performance class data records resource usage per transaction: CPU time, file I/Os, DB2 calls, storage used, and response time.
• Exception class data records unusual events, like a task waiting too long for storage or a file.
• User data lets the application add its own fields, such as order number or customer id, using the DFHMCT macro or EXEC CICS MONITOR.
• Turn on only the classes you need. Performance class data is enough for most tuning work.

Controlling monitoring

• Use CEMT SET MONITOR ON or OFF to start or stop monitoring without restarting CICS.
• Use CEMT SET MONITOR PERFORMANCECLASS and EXCEPTIONCLASS to control which classes are recorded.
• The DFHMCT macro defines which fields are collected and their positions in the SMF record.
• Analyze SMF 110 records with CICS Performance Analyzer or your own batch reports.

Example: adding user data with EXEC CICS MONITOR

• A program can write its own data field into the monitoring record. Define the field first in DFHMCT with an entry name.
• WORKING-STORAGE SECTION. 01 WS-ORDER-NUMBER PIC X(10) VALUE 'ORD0001234'. PROCEDURE DIVISION. EXEC CICS MONITOR POINT(100) ENTRYNAME('ORDERNUM') FROM(WS-ORDER-NUMBER) FLENGTH(10) END-EXEC.
• POINT is a user number, ENTRYNAME must match the name defined in the DFHMCT macro, and FROM gives the data.
• This lets reports show business data, like order number, next to CICS performance data.