Why am I doing this?
Even a well-executed Load Testing effort may fail if it does not answer the right questions…or answer them in the right way. The “right questions” might appear obvious, such as “How many hits/sec can the server handle?” Such questions, while well-intentioned, may not be the questions that really need to be answered. They may simply be the easiest questions to ask…and answer.
From a higher-level strategic level, the real questions sound something like:
1. Is this system ready to deploy?
2. Can we make this system available to another 350 users?
3. We deployed the system and the performance is … Continue reading »
We recently had a case of debugging a testcase where Load Tester reported an error with a page that looked and appeared just as it should, except it was missing a link the user needed to move forward. Debugging this case was easy: examine the replay two pages prior to the error, and the server had added a red error message to the page indicating the selected criteria was not valid.
So why didn’t Load Tester flag this error from the server? Beneath the error message, the page was exactly identical to the expect page: form fields were present and filled … Continue reading »
When I first started writing test cases with Load Tester, I found it easy to fall into the psychological trap of writing functional test cases. But load testing requires a different approach, and inadequate tests can cost you time and money.
Functional test cases (such as the unit tests popularized by JUnit) confirm the correctness of a system. These tests should be highly specific and have excellent code coverage. A good engineer approaches functional testing as though she were designing a jet engine: if any screw, flange, or circuit fails then the entire system is completely … Continue reading »
There are a few errors that are frequently reported by customers. One of them being the missing user variables error. A missing user variables error basically means that a variable that was suppose to be extracted on an earlier page was not extracted, and the user is now trying to use that variable. The error can be caused by a number of things, the most common are server connectivity issues and improper configuration of a dynamic value.
If the missing user variable error was caused by server connectivity issues, there tends to be a server error before … Continue reading »
We’ve seen that modern browsers have made great strides to improve efficiency in rendering and javascript performance. But, the differences seem to be less noticeable when the network is stubborn. On a recent trip, I ran into just this problem. During the evening, the hotel’s local Wi-Fi seemed at peak capacity, the DNS servers were sluggish, and just getting connections opened often added a couple seconds. Getting onto common sites like Slashdot seemed to take 30 seconds or more from the overburdened local connection.
This seemed like a golden opportunity to try out one of Opera’s new features: Opera … Continue reading »
In most cases Load Tester handles a file download during a testcase automatically. Fundamentally, there is no difference between downloading a spreadsheet or an image on the page. But in some cases, Load Tester does not automatically handle the dynamic URLs used in certain situations. Most commonly, these are cases where the file is being generated on-demand and is assigned a unique identifier that is part of the URL path, rather than a query parameter. In these cases, because there is no unique identifier that can be used to locate the value (i.e. a form field name or query parameter … Continue reading »
We are well into the development schedule for the next release of Load Tester – version 4.2. There are a number of great new features on the way as well as some enhancements to our underlying architecture that will enable Load Tester to handle far more complicated testcases in future versions.
One of the features coming soon is a version of Load Tester for 64-bit Windows. Load Tester can run on 64-bit Windows, of course, but it currently runs as a 32-bit process and is subject to the same limitations as if it were running on 32-bit Windows. Testers working … Continue reading »
With Load Tester 4, we’ve made it easy to harness Amazon’s power for Load Engines quickly and inexpensively. Once you’ve familiarized yourself with the basics, here are a few rules of thumb:
1. Get to know the Amazon EC2 Console . The console will quickly tell you what instances you have running – and subsequently what you are getting billed for.
Note that the console shows you only data for a selected region, so you should check each region separately. Load Tester will automatically prompt you after a test and before shutting down Load Tester if you have running engines … Continue reading »
NACON Consulting, provider of cyber security training solutions for the defense community, was aware of the concurrent user limitations of their online learning management system. In preparation for a major version release for an important client, COO Kent Leonard told his team that he wanted to see an improvement in performance, with documented proof that the system could not only handle the client’s required user load, but exceed it. “In my eighteen years of experience in IT development, I’ve found that testing is typically not as robust as it should be. I wanted to change that and do proper testing,” … Continue reading »
When a testcase has a file upload in it, Load Tester automatically handles the file upload during replays and load tests. However, in many tests each user should upload different file contents (and possibly use a different file name). Load Tester has streamlined this process to make it very easy to handle. Just follow these easy steps:
1) Gather the set of files to be uploaded
2) Import them into Load Tester (Window > Preferences > Web Performance > File Upload) and generate a dataset
3) Find the file field in the testcase using the Fields View
4) Configure the field to use the … Continue reading »