All About Caching and How Visual Studio Simulates Browser Caches

Simulation of Browser Caching during load tests In a VS load test that contains Web tests, the load test attempts to simulate the caching behavior of the browser.  Here are some notes on how that is done: There is a property named on each request in a Web test named “Cache Control” in the Web…


How to Export Perfmon Counter Values from the Visual Studio Load Test Results Database

How Are Perfmon Results Stored When Visual Studio collects perfmon data during a load test, it stores the data in the SQL database using four tables that allow it to normalize the data into a relational hierarchy. The four tables are: Dbo.LoadTestPerformanceCounterCategory – holds the list of machine names and counter category names (such as…


How many vUsers can my machine run?

I just love this question. It has such a simple answer…. Right? (uh, yeah. Sure). You can start off with this post from the product group ( , which is as good a starting place as any, but as a teammate just said “That’s sort of a ‘Your Mileage May Vary’ answer. Right?” Yep, it is….


Explanation of V.S. Load Test warm-up, load patterns, and cool-down, and how this affects the reported results

These graphs show what test iterations are stored and reported in the results of a Visual Studio load test based on the load pattern and warmup used. It is important to note the following things when considering the results: If the test’s active run settings is set to store “All Individual Details” then all iterations…


Explanation of “Off-Box Inclusive Testing” and how it impacts results and troubleshooting

Explanation of “Off-Box Inclusive testing” and how it impacts troubleshooting An “Off-Box” request is any request that is made by a client to a machine that is not part of the core environment. As an example, if a user opens Internet Explorer and goes to the main website, Internet Explorer will go to the…


Random Data Generator

This tool is used to create realistic random data for use in performing load testing. It includes a PowerPoint that discusses the importance of good data and includes information about how the tool generates data you can use.