JMeter "if controller" with parameters? - jmeter

Question

I was reading the JMeter documentation and came across this info box about "If Controllers":
No variables are made available to the script when the condition is interpreted as Javascript. If you need access to such variables, then select "Interpret Condition as Variable Expression?" and use a __javaScript() function call. You can then use the objects "vars", "log", "ctx" etc. in the script.
I don't quite follow this. Does this mean if I want access to a "User Defined Parameter" then I can access it only by writing some JavaScript? The example that follows this box then refers to "${COUNT}"
Could someone clarify the usage of the If Controller, maybe with an example or two?

Answer 1

All these answers are wrong! You need to put the variable reference in quotes, like so:
"${my_variable}"=="foo"

Answer 2

You can simply use something like
${my_variable}=='1'
Sometimes JMeter documentation can be confusing :)
Edit 27 september 2017:
The answer here works but has a very bad performance impact when number of threads exceeds 40.
See below for correct and most performing answer:
https://stackoverflow.com/a/46976447/460802
See:
https://bz.apache.org/bugzilla/show_bug.cgi?id=61675

Answer 3

UNCHECK the CHECKBOX
"Interpret condition as variable expression"
I wasted a couple of hours without unchecking this checkbox. It worked with and without semicolon(;) at the end of the statement. Make sure that you have set the User-Defined Variables before calling the if controller.
All the following variations worked for me in Jakarta Jmeter 1.5
${__javaScript("${HOMEPAGE}"=="Y")}
${__javaScript("${HOMEPAGE}"=="Y")};
"${HOMEPAGE}"=="Y"
"${HOMEPAGE}"=="Y";

Answer 4

If Controller will internally use javascript to evaluate the condition but this can have a performance penalty.
A better option (default one starting from JMeter 4, see https://bz.apache.org/bugzilla/show_bug.cgi?id=61675) is to check "Interpret Condition as Variable Expression?", then in the condition field you have 2 options:
Option 1 : Use a variable that contains true or false. For example If you want to test if last sample was successful, you can use
${JMeterThread.last_sample_ok}
or any variable you want that contains true/false
${myVar}
Option 2 : Use a function (${__jexl3()} is advised) to evaluate an expression that must return true or false.
For example if COUNT is equal to 1:
${__jexl3("${COUNT}"== "1",)}
OR
${__jexl3(${COUNT}== 1,)}
Starting with 4.0, if you don't use the "Interpret Condition as Variable Expression?", a warning in RED will be displayed:
If you'd like to learn more about JMeter and performance testing this book can help you.

Answer 5

God bless the http://habrahabr.ru
Have tried until found these.
Using the quotes was my solution.

Answer 6

As Gerrie said you need to check your variable
${my_var} == 'value'
But be careful with the 'User Defined Variables'
Note that all the UDV elements in a
test plan - no matter where they are -
are processed at the start.
That basically means that you cannot define 'User Defined Variables' inside an 'If Controller'. Take a look to the 'BeanShell' instead.

Answer 7

Replace:
${my_variable}=='1'
with
"${my_variable}" == "1"

Answer 8

if it's string value pass as below and its performance effective
${__groovy("${key}"=="value")}

Answer 9

I have used ${code_g1}== 200 in condition and it worked for me.