Log data accessible to DFHJUP

DFHJUP is able to read both active and inactive data on the log stream. Active data is data that has not been deleted via an MVS™ IXGDELET request. Inactive data is data that has been deleted via an IXGDELET request, but which has not yet been physically deleted by MVS because of the retention period specified for the log stream.

As mentioned in Managing the size of log streams, if you are running under OS/390® Release 3 or later you can use the MVS RETPD parameter to specify a retention period for a log stream. If you specify a RETPD value greater than zero, MVS physically deletes data from the log stream only when both the following conditions are met:

  1. The data is older than the retention period.
  2. Either of the following applies:

For definitive information about using the RETPD and AUTODELETE MVS parameters to automate the log tail deletion process, see the CICS Transaction Server for z/OS® Installation Guide.

Example

Assume that you have defined a CICS system log with RETPD(10) and AUTODELETE(NO). The active portion of the log stream will consist of the data that CICS has not marked for deletion. The inactive portion of the log stream will consist of the data that CICS has marked for deletion, but which MVS has not yet physically deleted--because it is less than 10 days old.

Figure 15 shows active and inactive data on a log stream with a RETPD value of 10.

Figure 15. Active and inactive data on a log stream. The log stream has been defined with a RETPD value of 10.
 The figure shows that data from a log stream can be in three different states: physically deleted, inactive, or active. For this example log stream, the RETPD value is 10. Data from this log stream is physically deleted when it is ten days old, provided that either AUTODELETE is set to YES, or an IXGDELET has been issued against the data. Data from this log stream is inactive if an IXGDELET has been issued against it, but it is not yet ten days old (so not old enough to be physically deleted). Any other data from this log stream is active -- it is not yet ten days old, and no IXGDELET has been issued against it.

The report output by DFHJUP advises you whether each block of data was read from the active or inactive area of the log stream--see Figure 16.

Related reference
Reading log streams using batch jobs (for example, DFHJUP)
SUBSYS=(LOGR,DFHLGCNV,...) keyword
Using DFHJUP to read log streams
DD statements for DFHJUP or your own batch job
Utility control statements for DFHJUP
DFHJUP return codes
Managing the size of log streams
Diagnostic information in DFHJUP output
Examples of using DFHJUP
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