Real-time exclusion processing

While real-time analysis is never performed if the primary subsystem (JES) is unavailable, there are a number of ways to selectively exclude various elements of the Z Abend Investigator processing, as illustrated in Real-time exclusion processing overview.
Figure 1. Real-time exclusion processing overview

Diagram showing the real-time exclusion processing logic: Starting at the invocation exit, is the HFZOFF DD allocated? If yes, then processing ends without performing analysis. If no, then is it an HFZSNAP invocation? If yes, then proceed with analysis. If no, then is it a Fast Exclude match? If yes, then processing ends without performing analysis. If no, then is it a CICS transaction abend? If no, then proceed with analysis. If yes, then is it a CICS dump table excluded abend? If yes, then processing ends without performing analysis. If no, then is it a Fast NoDup match? If yes, then processing ends without performing analysis. If no, then proceed with analysis. The HFZDA analysis module logic follows. First options processing is performed. Is it an Exclude match? If yes, then no further processing is performed. If no, then fault analysis is performed. Is it a Normal NoDup match? If yes, then no further processing is performed. If no, proceed to generate the analysis report and create a fault entry.

Notes:
❶
By providing an allocation of DDname HFZOFF to the abending job step, Z Abend Investigator processing is immediately terminated without producing an analysis report or writing a history file fault entry. You can do this, for example, adding the following JCL statement in your JCL: 
//HFZOFF   DD      DUMMY
Allocating HFZOFF is the quickest way to prevent Z Abend Investigator from running for a particular job step, and the one which is recognized with the least amount of overhead.
Note: In the z/OS Unix System Services environment, setting the environment variable _HFZ_OFF to "Y" is equivalent to using the HFZOFF DDname switch. For more information, see Turning off Z Abend Investigator using an environment variable (_HFZ_OFF).
❷
If calling HFZSNAP from within your application (see Using the program SNAP interface (HFZSNAP)), then no further exclusions are available prior to options processing being performed.
❸
If fast Exclude options processing is enabled, and the job is eligible (see Fast Exclude options processing), then a matching Exclude option (see Exclude/Include) can be used to terminate Z Abend Investigator processing early.
❹
Additional invocation exit exclusions are provided for CICS® transaction abends only.
❺
If the CICSDumpTableExclude option is in effect (see CICSDumpTableExclude), and the CICS® transaction abend that is associated with the fault is specified in the CICS® transaction dump code table to not require a CICS® dump, no further processing is performed. That is, no analysis report is produced and no fault entry is written.
❻
If either of the following is true, processing terminates for the current fault:
  • The NODUP(CICSFAST(…)) option specifies a non-zero number of minutes, and the criteria used for determination of duplicate CICS® transaction abend fault entries match.
  • The NODUP(IMAGEFAST(…)) option specifies a non-zero number of minutes, and the criteria used for determination of duplicate IMS™ transaction abend fault entries match.

Although no analysis report is produced and no history file fault entry is written, the duplicate count is still updated in the history file cache against the fault entry when the next non-duplicate fault entry is written.

For details about these fast duplicate detection options, see NoDup.

❼
The EXCLUDE option (see Exclude/Include) can be used to terminate Z Abend Investigator processing once the options have been read in the mainline code.
❽
Prior to writing the history file fault entry, the NODUP(NORMAL(…)) option is checked. If the option specifies a non-zero number of hours and the criteria used for determination of duplicate fault entries match (see NoDup), then processing terminates for the current fault. The real-time report is written to HFZREPRT, but no history file fault entry is created.

Note that the NODUP(NORMAL(…)) option applies to all fault entries, including CICS® transaction abend faults.

Unless Z Abend Investigator processing is excluded using the HFZOFF DDname switch, then an SMF type 89 record is written to indicate Z Abend Investigator usage.