IBMi Troubleshooting – History log


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Applies to: IBMi Servers


History log

The history log is a database file that is tagged with CCSID 65535. The system copies the messages in the QHST message queue to the history log files and then removes them from the QHST message queue.

The history log (QHST) contains a high-level trace of system activities such as system, subsystem, job information, device status, and system operator messages. Its message queue is QHST.


Displaying the list of history log files

  1. To view a list of history log files:
    • Use the Display Object Description (DSPOBJD) command 
    • The files reside in the library QSYS and begin with letters QHST, followed by a number.

      2.  To display the list of history logs and to view its contents:

    • Type WRKF QHST* from any command line.
    • Select option 5 to display the contents of the file.
    • Type DSPLOG from the command line. The Display Log (DSPLOG) command uses the history log files to show the messages sent to the QHST message queue.


 QHST files deletion

A log version is created such that only the security officer is authorized to delete it:

  • The Operational Assistant provides a cleanup function which includes the deletion of old QHST files.
  • Another alternative as a security officer, specify:
    WRKOBJ OBJ(QSYS/QHST*)OBJTYPE(*FILE)Use option 4 to delete old unneeded files.


System Values

  • You can use this system value to specify the maximum number of records in the history log.
    QHSTLOGSIZ – Maximum records in history log
  •  You can use this system value to specify whether to display status messages or not.
    QSTSMSG – Display status messages

Note: Log version physical files accumulate on a system and you should periodically delete old logs that are not needed.