z/OS Diagnostic Data Collection and Analysis

11.6. CICS internal trace

Possibly the most useful diagnostic information that can be reviewed in a CICS SVC dump is the CICS internal trace. A record of all activity within the CICS region is stored. The default tracing options only capture exception trace entries. Unfortunately, we usually like to review what preceded the generation of an exception condition, as this is the only way to see what was the cause, not just the result.

Another unfortunate default is the CICS internal trace size, which is set to 64K. In a busy CICS region this would store less that one second of trace data – hardly enough to enable you to review the flow of the transaction that caused the exception condition. We recommend an internal trace size of at least 2500K. ...