This document explains what the "Lost" column value in the "Queue processing subtask statistics - collection totals" section of the "Detector Collection Detail Display" means.
What does the "Lost" count on the Collection Detail Display mean?
z/OS 1.11 and above.
The "Lost" count relates to the Message PXM3200 which is issued in the xmanager log when the collection task cannot keep up with the volume of metrics being passed to it. You can review this message to find the percentage of data loss.
This message means that the tasks in the Xmanager address space are not being dispatched quickly enough to keep up with the incoming work. The Xmanager address space needs a higher dispatching priority than any allied address space that executes SQL.