Managing history files (HFZUTIL utility)

The HFZUTIL batch utility can be used to perform history file management functions, such as listing and deleting history file fault entries.

The ability to delete a set of entries based on their date or some other criteria enables you to keep the number of entries in the history file at a manageable level.

Note: Do not delete members from a history file PDS or PDSE outside of the Z Abend Investigator ISPF interface or the HFZUTIL batch utility (for example, directly from an ISPF data set member list). If you do, the history file index is out of synch until the recording of the next fault during real-time analysis or a run of the HFZUTIL batch utility against the history file.

Being able to list the entries in history files can help you to keep track of problems.

The maintenance functions of HFZUTIL are driven by a series of control statements that it reads from the SYSIN DD JCL data set. The control statements start in column 1 of the SYSIN records with any continuation statements having a blank in column 1. Comments can be placed in this control statement stream with an asterisk in column 1 of the comment line.

The SYSIN stream is processed sequentially, one control statement at a time. The target history files for control statements can be implicit or explicit depending on the control statement. The control statements that set up target history file data set names overwrite the target history file names previously in effect. The FILES control statement's only purpose is to set the target history file data set names for following control statements. This purpose makes sense when you see that the LISTHF and DELETE control statement syntax does not include a target history file keyword. They operate on the current target history file set, which can be one or more data set names.

Other control statements such as IMPORT and SETFAULTPREFIX carry a single history file in their syntax which resets the current history file set to that data set name, before carrying out its action.

As an alternative to the SYSIN stream, control statements for the HFZUTIL batch utility can be passed via the EXEC JCL statement PARM field. Control statements passed in this way must not include any imbedded blank spaces, but must be separated from other control statements by one or more blanks.

The HFZUTIL batch utility provides basic capabilities including selection of fault entries to list or delete based on criteria such as date and job name. Three user exit points permit more advanced selection and recording to be coded by the user. These exits are for the DELETE, LISTHF, and IMPORT control statements. They follow the same structure as the user exits provided with the Z Abend Investigator real time and reanalysis functions. They can be written in REXX, Assembler, or a high-level language.