Maintaining Performance History Files
These methods are available for maintaining Performance History Files.
- 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.
- 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.
- 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
(for instance, resetting the interval count might result in the re-use
of a previously assigned interval number). To delete all Performance History Files:
- Stop the Query Monitor Subsystem.
- Delete the INTERVAL data set.
- Use ISPF option 3.4 to delete the unwanted Performance History Files.
- Redefine the INTERVAL data set using SCQMSAMP library member CQMINTER.
- Set the RETAIN start-up parameter to the desired value (minimum of 3).
- Restart the Query Monitor Subsystem.