IBM BPM, V8.0.1, All platforms > Authoring services in Integration Designer > Developing monitor models > Debugging monitor models > Stepping through a running monitor model
Viewing data while debugging
To view data while debugging a monitor model, you can use the Variables view or the Instances view.
You cannot change values in these views.
Variables view
The Variables view shows data only when an inbound event is being processed. After an inbound event arrives, you can inspect the content of the event in the Variables view by opening an event and inspecting the event attribute details.
After one or more monitoring context instances have been created or selected by correlation processing, the Variables view shows not only the values of the inbound event but also the value of anything in your active monitoring context instance (such as metrics, stopwatches, and counters) that has a value. (If a metric has not yet been set by a previous step in your debugging session, and does not have a default value, it will not be shown here.) As you step through your model in the debugger, the Variables view shows the values in a context while the event is being processed in that context. The last value that has been updated is highlighted in yellow. As you move to another context during your debugging session (either repeating the low-level steps for another context, or passing the next inbound event definition in the high-level steps list), the Variables view changes to reflect the new context that is being debugged.
If nested monitoring contexts are defined in the monitor model, click a monitoring context identifier in the Debug view to show its associated data in the Variables view.
KPIs are shown when the event is processed in a KPI context. Measures are shown when the event is processed in a cube.
In addition to the values of the current inbound event, the Variables view shows the contents of outbound events as they are created and sent from the debugger.
Instances view
The Instances view shows all of the monitoring context instances (or KPI contexts, or cubes) that exist, including the one that is in scope for the current event as well as all the ones that have been created by previous events and are not currently being updated. It provides a system-wide view of the values of all metrics, counters, stopwatches, and so on in the running monitor model.
The contents of the Instances view are refreshed automatically when you are stepping through the processing of an inbound event. You can also refresh the Instances view by clicking Refresh 
.
An instance that is not a target of the current event is not in scope while the event is being processed, but the metrics of the instance are still used in calculating aggregations for KPIs and measures. The Instances view can help you investigate why a certain value was the result for a KPI or measure.
As another example, imagine that you processed an Order Canceled event for order #54321 and you expected the event to be delivered to the monitoring context instance that tracks the fulfillment of that order. Instead, the event is put into the retry queue. You might then want to use the Instances view to inspect the existing instances, to understand why none of their correlation expressions matched the correlation criteria for this event.
You can also view parent and child instances in the Instances view. Child instances are shown in a parent instance using the plus sign (+), which you can click to view the values.
Metrics, measures, and KPIs that are defined in the model but have not been initialized with a value are not shown in the Instances view. When a metric is listed with no apparent value, its value is the empty string, which is different from the metric having no value at all (and not appearing in the view).
After an event has been processed, the Variables view is empty because there is no active context, but the Instances view still shows you the details of all instances that have been created.
You can clear the terminated instances by restarting the debugger using the Clear data from previous debug sessions check box.