Update Parameter Value at Each Occurrence

Problem:

  • How to update the parameter value taken from the CSV file at each occurrence in an iteration in JMeter?
    Or
  • How to pass a new value of a parameter fetched from the CSV file in the same iteration in JMeter?

Explanation:

When a new iteration starts in JMeter then a value gets assigned to the parameter from the CSV file (when CSV Data Set Config is used for test data). This assigned value remains the same across the iteration. But in some scenarios, a new value of the parameter needs to be passed at each occurrence of the parameter within the same iteration.

Note: LoadRunner has an option “Each Occurrence” under the “Update Value On” attribute in the Parameter List. This option helps to update the value every time when the parameter appears in the script within the same iteration.

Solution:

Add the same CSV Data Set Config element as a child of the request where the next parameter value needs to be passed. This child element will fetch the next value present in the CSV file.

Example:

A CSV file contains below values:
perfValue01
perfValue02
perfValue03
perfValue04
perfValue05

Consider, there are 2 more occurrences of the same parameter in an iteration. Each occurrence of the parameter (in Request 3 and Request 4) should have a new value from the CSV file. Refer to the screenshot:

Update Parameter at Each Occurrence in JMeter
Figure 01: Add ‘CSV Data Set Config’ as a child element of the request

See the result:

Update Parameter Value at each occurrence in JMeter
Figure 02: View Results Tree

Important Point:

If samplers (requests) are in the same transaction controller then JMeter will not update the parameter value and pass the same value in each occurrence. Hence it is recommended to add the samplers in a separate transaction controller.


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