How is the user load adjusted for a load test with a goal based load pattern?

This post describes how the user load is adjusted when a load test scenario uses a goal based load pattern.    First of all, if there is a warm-up period specified, the goal based pattern does not apply during the warmup period.  Instead, the load test creates a temporary step load pattern that is used during the…


Hot fix available for think time bug introduced in VSTS 2008 SP1

There is now a hot fix available at for the bug introduced in VSTS 2008 SP1 where think times were being ignored during a load test for Web test requests that resulted in redirect responses (described in my earlier post:  


Collecting SQL counters from a non-default SQL instance in a VSTS Load Test

If you want to collect performance counters from a SQL Server instance while running a load test, you can do this easily by selecting checking the SQL counter set in the “Manager Counter Sets” dialog in the VSTS load test editor.   Doing this includes the default counter set for SQL Server in your load test.   The performance…


Diagnosing OutOfMemoryExceptions that occur when running load tests

We’ve had a number of users report OutOfMemoryExceptions occurring in the QTAgent process (or the VSTestHost process when running locally).     There can be several different causes of the OutOfMemoryExceptions.   This article attempts to help diagnose and prevent these problems.    First a bit of background information: the QTAgent.exe and VSTestHost.exe processes are both 32-bit processes in…


Bug in VSTS 2008 SP1 causes think time for redirected requests to be ignored in a load test

Unfortunately, late last week we discovered a nasty bug with load testing in VSTS 2008 SP1 that is a regression from the original RTM version of VSTS 2008: for Web test requests that result in redirects, any think time that is specifed on the request is ignored when the Web test is run in a load test.   Even more…


Running Load Tests with VSTS 2008 SP1 requires that SP1 be installed on VS client, controller, and agents

As mentioned in previous blog posts, the beta version of VSTS 2008 SP1 is now available.   In order to implementation the Load Test API enhancements (described here: we moved some of the classes that are used to implement the different load test patterns into the LoadTestFramework.dll to make them public and also changed the…


Disabling caching of all dependent requests

 In a previous blog post here:, I described the behavior of caching with VSTS 2005.     With VSTS 2008, the default caching behavior is the same.   However, with VSTS 2008, if you want completely disabling caching of all dependent requests and always fetch them, you can so by adding the following WebTestPlugin to your Web test:     public…



This is my first blog post of a personal nature.   I heard on TV this morning that today marks the 40th anniversary of the assassination of Bobby Kennedy (     Today though I’m remembering another great American who died a year ago today: my oldest son Thomas who was 22 years old.   You can read his somewhat heartbreaking…


Articles Posted on Web and Load Test API enhancements available in VSTS 2008 SP1 beta

The beta for Visual Studio 2008 SP1 is now available and includes enhancements to both the Web test and load test APIs that are described in these articles: