Load Testing Blog
How HTTP Authentication works and why load testers should care
The most commonly used authentication method for websites is a login form on a web page. We’ve all seen them – enter your username and password into fields on the web page and press the Submit or Login button. From the standpoint of the underlying technology, this is no different than submitting any other form – only the names of the fields distinguish them as login or password fields and the security mechanism is implemented within the web application.
The next most common form is authentication via … Continue reading »
What’s new in Load Tester 4.2
The 4.2 release focuses on platform compatibility and productivity increases from our services work in the past year with such clients as the US Census and the New York Marathon.
With a slew of new browsers and operating systems available, this release also includes support for 64-bit Windows and AIX operating systems, the latest versions of Internet Explorer, as well as the Chrome and Safari browsers.
On the productivity side there are some pretty big changes to allow testers to configure more complex testcases with less effort than ever before. Some of … Continue reading »
Load Testing Data Population: How Many Rows?
A common problem when setting up a load testing configuration in Load Tester is figuring out how many rows of data you need for a particular test. For example, you need to have a set of user names and passwords to be used during the test, but how many do you need to ensure that the test will complete?
To answer this question, you need to know three things: the duration of the test, the expected duration of the test case, and how many concurrent users the test will simulate. … Continue reading »
How To Manually Modify HTTP Requests in Load Tester 4.2
In older versions, Load Tester provided a simple interface for modifying the URI portion of an HTTP request. For example, you could add a query parameter or a path segment by adding it directly to the request line in the Edit HTTP Request-line/URL dialog.
In Load Tester 4.2, this process has been made slightly more complex but vastly more powerful. We’ll start by manipulating the URI field directly. To do so, select the specific transaction you wish to edit, then select the Fields View, … Continue reading »
Load Testing Basics: How Many Concurrent Users is Enough?
The most common question regarding a website’s performance is not how fast the website is or how it scales, but something more fundamental:
What should the performance goal be in terms of concurrent users?
Should it be one hundred concurrent users? A thousand? Ten thousand? Does it require one server or a hundred to handle the load?
There’s a good reason for how many times this question comes up: it’s tricky and there’s no definitive answer. If it is a new website it’s anyone’s guess what the … Continue reading »
Load Testing Back to Basics: Avoiding the KeepAliveTimeout Race Condition
You’ve recorded your test case, configured your datasets, and run your replays. You start up the load test and … you see numerous errors like this:
“The connection with the server was unexpectedly closed before starting the response.”
What’s going on? Well, one common reason for this error is a connection-related race condition between Load Tester and the web server due to the server’s configured persistent connection timeout.
Persistent connections are an HTTP mechanism for minimizing network connection overhead between the browser and the web server. If the client … Continue reading »
How-To: Updating Recorded URLs
We sometimes get support questions where a customer has recorded a site using one URL and would now like to use the same recording on a different URL. If the content on both servers is very similar, for example if one is a production server and the other is a development server, a re-recording of the site may not be necessary. Simply replacing the recorded URLs with the new server’s URLs could be all that is needed to get the recording working with the new server. Below are the steps on how … Continue reading »
IE8, favicon.ico and silly server stunts
At first glance, load testing software seems like it should be pretty straightforward. And like most things, it turns out to be really complex — at least, if you want to do it well. Simulating a browser could be pretty easy – except for the need to do it very, very, very efficiently, so that the solution can scale to simulate hundreds or thousands of virtual users per computer.
What does this have to do with favicon.ico and IE8? Occasionally while helping a customer use Load Tester, we run into some … Continue reading »
AIX Monitoring Support on the Horizon
We’ve got a lot of new exciting progress making it’s way into Load Tester 4.2. Among these features, Load Tester 4.2 will be introducing an Advanced Server Analysis™ module designed for AIX servers. Like our other Advanced Server Analysis™ agents, the AIX module is capable of running offline, and will continue to collect data about your server even when normal connectivity to the server has been overloaded (unlike some of our competitors solutions). The monitoring agent can collect vital information from your server, including:
CPU
Memory
Disk activity … Continue reading »
Load Testing Anti-Patterns: Building the Perfect Test
We run into a wide variety of customers who need load testing software and/or services. While many are working their way through the process on-the-fly, others have toiled long and hard to develop a thorough testing plan, complete with detailed descriptions of exactly how the load test should be performed. On occasion, this testing plan is incredibly specific – detailing exactly how many users should be doing this or doing that, exactly how many users should click a button at the same time, exactly which search result the user … Continue reading »
