Prior to v5.0, when a parameter was databound to a dataset, the databinding method is specified on that parameter level (as described here). Starting in v5.0, databinding can also be defined on the dataset level.

The key benefit to databinding on the dataset level is that it is easy to change the databinding mode of all parameters in one place instead of deleting and recreating all parameters as required in the previous versions.

Default databinding mode

The default databinding mode can be changed in the property grid below the dataset.

There are available six modes:

  • VU-Bound
  • VU-Iter-Bound
  • VU-Iter-Random
  • Iter-Bound
  • Iter-Req-Bound
  • Req-Bound

All are described here.

Create parameter with default databinding

When creating a parameter using a dataset with default binding, select the column name to bind to in the variable picker. You do not have to select the databind method as described here.

When the parameter is created, the databind method will say Dataset, which means the default dataset binding will be used for this parameter.

Override default databinding mode

To override the default databinding method (or return to the previous version of creating parameters), set the Hide advanced databinding selection property to No.

That will show all available databinding methods in the variable picker.

Mapping VUs to dataset rows

By VU number

VU-bound and VU-Iteration-Bound both, by default, use the VU number to calculate which dataset row will be bound to a particular parameter. The advantage of this approach is that it is known ahead of time which record will be used for which VU and iteration. 


In V5.8, only the VUs that use the dataset are considered when calculating row mapping. This removes the need for padding the dataset with dummy data that will never be used. 

Changing VUs during the test run

If the test has a unique data row constraint, then By VU number mapping will not work for tests that have changed VUs during the test run.


This will assign rows to parameters on a first-come basis in run-time on-demand only for VUs that actually require data binding. Since the rows are assigned on-demand, there is no way to tell ahead of time which row will be assigned to which parameter. This method supports changed VUs during the test run

Distributed testing

To use this method in a distributed test where VUs from different load agents share this dataset, agent-designated data is required. 

When the last record is reached

During a test, in the event, a virtual user needs a new record from the dataset, but the dataset does not have any new records left, StresStimulus can perform different actions by setting the dataset property Action after reaching the last Dataset record to the following values:

  • Round-robin (default): starts using the dataset records from the beginning.
  • Use last: continue using the last record until the end of the test
  • Abort VU: abort executing the current VU.

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