First HTTP request is taking more time than usual

Question

First Business transaction:

• First HTTP request - performing edit functionality on the Add User Page (Login --> Homepage --> Adduser) is taking more time than usual. (Delay in launching URL)

Second Business transaction:

• First HTTP request - performing edit functionality on the Add Registration Page(Login --> Homepage --> Registration) is taking less time. (Now it's working very fast)

Could you please guide me on why the application behaves like this?

Answer 1

Most often this is configuration of the web-application. Each service used could have a cold-start/sleep. The service goes to sleep after X time of being idle, this to save resources. Or it needs to compile/load the run-time after a reboot. Some of our application that run on MS InternetInformationServices take upto 25 seconds to start for the first call.

So verify that in production this disabled. You could argue that this might not be an issue in production if your application has users worldwide, because someone would always keep the application alive.

In your tests you could add a wait time for the first call, or disable the auto sleep of the (web)-services in your environment if possible.

Reads:

• https://softwareengineering.stackexchange.com/questions/97538/why-after-each-restart-my-local-net-sites-take-time-to-load-for-the-first-time
• https://mikhail.io/serverless/coldstarts/aws/

Answer 2

If you have HTTP Cache Manager in the test plan that explains everything because so called "embedded resources" - images, scripts, styles, fonts, sounds, etc. take the most bandwidth while HTML response is comparably small.

So when you execute the very first request to the application each JMeter thread (virtual user) downloads all the content from the server and when you make the second request the content is being returned from the cache manager so no actual requests for "heavy" content items are being made.

More information: HTTP Caching