Performance Testing for AJAX-based Applications

http://www.aztecsoft.com/downloads/Aztecsoft_Whitepaper_Performance_Testing_AJAX-based_Applications.pdf

.............

The AJAX approach can yield a number of important advantages:

- Since the response does not contain the entire page, a smaller amount of data gets transferred across the network thus resulting in better network utilization.

- Instead of reloading an entire page, AJAX applications update only parts of the page, thus improving the responsiveness of the application.

On the other hand, a badly designed/tuned AJAX application can have a counter-productive effect. For example, an AJAX engine can send too many AJAX requests and increase, rather than reduce, the load on the network.

It is therefore imperative that an AJAX application be put through a thorough performance testing cycle before it is released for general use. We have selected "Google Suggest" as a real-world example so that our discussions retain a practical flavor.

.................

It would therefore seem reasonable to vary the frequency of AJAX requests in "Google Suggest" as a function of the network speed and the user's typing abilities, in other words to optimize the AJAX engine.

...................

"What is the function that currently determines the frequency at which the AJAX engine makes an AJAX request, where the two inputs are (1) observed server-reponse times and (2) observed user typing speeds?"

...................

Script designers need to gain a deep understanding of the AJAX implementation.

...................

There are two broad approaches that can be adpted - one can either embed the AJAX engine code into the test script in the form of a plug-in (the "heavy" model) or simulate it using the Load Testing tool's scripting functionality (the "light" model). The test scripter has to decide which approach to take based on a number of factors"

..................

Thus the approach of embedding the actual AJAX engine into the Load Testing script should be considered only in situations where this engine is very light-weight and does not make too many demands on the machine it is hosted on.

...................

Debugging test scripts is harder.