Most web applications use Epoch timestamp values, or current milliseconds from January 1, 1970. Since time is something specific to when an application and user is accessing the application, the value will eventually become invalid and need to be replaced with a variable that makes it dynamic. Some examples of unique dynamic values that web applications use are in the form of timestamps. The time saved can be significant, which makes your job easier and less stressful. This allows NeoLoad to search for dynamic values throughout your script and automatically handle the correlation. Once you identify what is dynamic in your script and create correlation for it (extraction using a regular expression and replacement), you promote it to a Framework. This can save hours and days designing and maintaining a script in preparation for load testing. Some tools, like Tricentis NeoLoad, can automate handling the many occurrences of dynamic parameters through a feature called Frameworks.

The handling of these static values so that they appear dynamically distinctive each time a load test runs is called correlation, or what many refer to as-as the bread and butter of “design.” Many of the best load testing tools aid in the identification and handling of dynamic parameters.

Some of these parameters include session IDs, tokens, timestamp values, and universally unique identifiers (UUIDs), and must be different every time the script runs. The initial static values are no longer valid and were usually specific to the original recording, but not suitable for any playback of the script. Why is this important? If left unmodified, these parameters with recorded values will play back to the server in their original value(s). With any typical user session accessing an application server, there are parameters (and values) that give this specific session its unique fingerprint. The “script,” in its raw form, is usually a recording of an emulated user interacting with the application. Designing a load test involves the creation of a script - a set of calls, requests, and actions to an application server.

Neoload pulling data from a table