Maintaining Performance History Files

These methods are available for maintaining Performance History Files.

Procedure

  1. Method 1. Reduce the number of retained intervals. (Recommended) The recommended procedure for maintaining Performance History Files is to allow Db2 Query Monitor to manage the data sets using the RETAIN start-up parameter. If you reduce the number of intervals retained (via altering the RETAIN start-up parameter) the excess Performance History Files are deleted via the IDCAMS DELETE command. This process can require long time periods if there are many Performance History Files to be deleted.
    Note: During this process, Db2 Query Monitor should not be canceled.

    If Method 1 does not meet your site's specific needs, then consider the alternate procedures:

    • Method 2: Manually delete Performance History Files, or
    • Method 3: Delete all Performance History Files and reset interval count to the desired limit.
  2. Method 2: Manually delete Performance History Files. You can delete Performance History Files using ISPF option 3.4.
    Note: If a data set is deleted and you attempt to access the deleted interval, message CQM149E is issued indicating a dynamic allocation error.
  3. Method 3: Delete all Performance History Files and reset interval count to the desired limit. If you want to delete all interval backstore data sets, you can do so using the following procedure. This procedure resets the interval count to 1 and therefore should only be undertaken with a full understanding of the resulting impact on your Db2 Query Monitor data (for instance, resetting the interval count might result in the re-use of a previously assigned interval number).
    To delete all Performance History Files:
    1. Stop the Query Monitor Subsystem.
    2. Delete the INTERVAL data set.
    3. Use ISPF option 3.4 to delete the unwanted Performance History Files.
    4. Redefine the INTERVAL data set using SCQMSAMP library member CQMINTER.
    5. Set the RETAIN start-up parameter to the desired value (minimum of 3).
    6. Restart the Query Monitor Subsystem.