How can I initialize sample variable in Jmeter?

Question

I have scenario as :

While Controller

CSV Data Config
  Switch Controller
    Register_Scenario
       HTTP Request
          HTTP Header Manager
          Regular Expression Extractor
       JDBC Request
          Response Assertion
    Cancel_Scenario
       HTTP Request
          HTTP Header Manager
          Regular Expression Extractor
       JDBC Request
          Response Assertion

View Result Tree

In my CSV I have multiple scenarios to Register and Cancel with different data Eg:

Scenario,Subject,StudentID

Register_Scenario,ABC,1

Cancel_Scenario,XYZ,5

Register_Scenario,MATH,200

I am running Web API and getting the output from Database in one variable(its in Json format in Database), I would like to store that response data coming from JDBC request into the CSV file:

My expected OUTPUT should be:

expected output

Now, I used sample variable in JDBC request in the "Variable names"=Json_Response

I ran the scenario using data mentioned above

I am getting this as output:

Actual output

I believe my result is generating twice as in one scenario I have HTTP request and JDBC request, However variable is defined only on JDBC request and not HTTP request. and for it stays same until value changes..

Dmitri T Dmitri T · Accepted Answer · 2017-01-09T04:18:06

If you don't like the null value when your Register_Scenario variable has not been initialized yet you can explicitly set its value to whatever you want (empty or something else) using User Defined Variables configuration element

How can I initialize sample variable in Jmeter?

1 Answers