KBI 311305 Message API HttpSendRequest Failed Can Happen When Doing Load Testing


Argent Defender all versions


Monday, 26 October 2015


When simulating more than 100 virtual users for load testing in Argent Defender, following message can be seen in task log many times:

(VUser# nnn) API ‘HttpSendRequest’ failed (http:…)

It is normal behavior for load testing

The virtual users encountering such API errors are those that are for generating loads only

When Argent Defender Engine simulates so many virtual users and generate so much network traffic, the machine NIC can be saturated

As a result, the WININET API calls might not be successful all the time

But that is expected

Argent Defender does not use the performance data from these virtual users who are intended for load generating only

Instead, Engine collects the performance data only from the virtual users that actually run the web session scripts

However, when NIC is saturated, the web session scripts might not be running successfully either

For heavy load testing, it is recommended to run the virtual users for load generating on a separated Trusted Agent other than the Engine that plays the actual web session script

Technical Background