How Db2 Automation Expert initiates object monitoring for reorganization recommendations

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The initial (setup) build of a Db2 Automation Expert job profile that specifies a REORG TABLESPACE utility, the QUERY PERFORMANCE REORG OVERRIDE exception, and at least one additional exception condition starts the interaction between Db2 Query Monitor and Db2 Automation Expert.

When the job profile is built, the following process is set into motion:

  1. Db2 Automation Expert sends information about the objects and the time period to be monitored (the performance window) to Db2 Query Monitor. The setup build initiates reorganization recommendation monitoring during the specified time period, so that Db2 Query Monitor can later make recommendations as to whether or not the objects need to be reorganized. During performance windows, the CAE server analyzes data for the intervals to decide whether to keep or ignore the intervals (if they do not have sufficient data).
    Note: Reorganization recommendation monitoring does not affect Db2 Query Monitor SQL monitoring.
  2. To start making recommendations, Db2 Query Monitor needs a baseline performance window. The baseline performance window is the first occurrence of the performance window after the last completed REORG for a table space and contains one or more Db2 Query Monitor intervals. Db2 Query Monitor checks to see when the last REORG was performed for an object and whether performance data has already been collected on the objects during the performance window that was passed in by Db2 Automation Expert.
    • If past intervals exist during which performance data was collected for the object and that precisely fit the time period, those past intervals are used to create the baseline performance window.
    • If the interval that contains the collected performance data does not precisely align with the requested time period, Db2 Query Monitor marks a larger period of collected intervals as the baseline performance window. For example, if you have four intervals of collected performance data:
      1 pm - 2 pm
      2 pm - 3 pm
      3 pm - 4 pm
      4 pm - 5 pm

      and Db2 Automation Expert requests the performance window from 2:30 pm to 3:30 pm, Db2 Query Monitor saves two intervals as the baseline performance window:

      2 pm - 3 pm
      3 pm - 4 pm

      In this case, the performance window (2:30 pm – 3:30 pm) overlaps these two Db2 Query Monitor intervals, which together include the full baseline performance window.

  3. Reorganization recommendation monitoring is started.