(This article is part of the JMeter Series)

Useful ways to debug JMeter as far as I know:

  • insert a “Debug Sampler”

the “Debug Sampler” will emit “everything that’s known” to JMeter. That output can be displayed in the “View Results Tree Listener”:

  • have a look at the JMeter log file (which is usually dumped from where you’ve started JMeter)

  • check the output of one of the listeners such as the “View Results Tree Listener”.

  • if you need to debug regexes of a “Regular Expression Extractor” then you can have a look at the source code of the page you want to extract a value from inside the “View Results Tree Llistener” and enter the same regular expression in the “Search” field (searching is only implemented in JMeter > v2.4).

In that picture you can see JMeter matching and displaying the regex entered in the search field inside an HTML page retrieved though the “HTTP Client Sampler”.

Tomáš Pospíšek, 1.1.2011