* - the task is a set of one or more client emulation activities with the same behavior.
** - one thread corresponds to one client activity emulator also known as a virtual user.
*** - one iteration corresponds to one or more transaction depends on the task definition and settings. In other words, it is one task's script execution.
All mentioned metrics are collected and stored at the client side where DTM DB Stress executing. The user should operate with system performance counters to add server side metrics to the report. Please refer to your DBMS manual for details.
The enterprise edition if the stress tool allows the user to compare results of a few job executions or different jobs results. It provides comparison results as HTML report (sample) or set of diagrams.