I think it is because a 'config element' is processed once when the test plan is loaded, but a 'pre-processor' is processed before each sample is run. There is a similar 'config element' called "User Defined Variables" that are processed at load-time for the test case. But bear in mind, if you use these - only the last one in the whole test plan is valid for a given variable. Whereas, if you use "User Parameters" those are valid for a specific sample based on the how they are defined as the test case is processing.
For example, say you have a test plan that looks like this: User Defined Variables: username = foobar Thread Group 1: (uses '${username}' variable) User Defined Variables: username = notfoobar In this case, when you run the test plan, the ${username} variable will be set to "notfoobar" - because the "User Defined Variables" are all processed _before_ the thread group runs - and the value is set to the last one that defined it. In example 2, we see User Parameters at work: Thread Group 1: User Parameter: username = foobar${__threadNum} Sampler A: (uses ${username} variable) Thread Group 2: User Parameter: username = notfoobar${__threadNum} Sampler B: (uses ${username} variable) In this example, Thread Group 1 will increment the 'username' value through "foobar1", "foobar2", etc. for as many different threads as you run through it. Likewise, thread group 2 will increment the username variable through "notfoobar1", "notfoobar2", etc. because the User Parameters are evaluated at the sample run time. -- Robin D. Wilson Sr. Director of Web Development KingsIsle Entertainment, Inc. VOICE: 512-777-1861 http://www.kingsisle.com -----Original Message----- From: Shmuel Krakower [mailto:shmul...@gmail.com] Sent: Monday, March 24, 2014 3:03 AM To: JMeter Users List Subject: User Parameters Pre Processor Hi, I was wondering why the User Parameters is a pre-processor rather than a Config Element? I just spent few minutes looking for it in the wrong place... ;) Best, Shmuel Krakower. www.Beatsoo.org - re-use your jmeter scripts for application performance monitoring from worldwide locations for free. --------------------------------------------------------------------- To unsubscribe, e-mail: user-unsubscr...@jmeter.apache.org For additional commands, e-mail: user-h...@jmeter.apache.org