Significance of Caching Detail report in Rational Performance Tester
What does the Caching Detail report signify in IBM Rational Performance Tester (RPT)?
Understanding the caching report information would help you to implement the best practices during the recording process in RPT.
If something is cached (like a .gif element ) during the recording process then at playback it will be cached (unless the server provides a new version of the file). It's the same as the browser. Note that the browser (or RPT) has no jurisdiction on caching, it is ultimately up to the server.
During the recording of a browser session in RPT, one of the things recorded is whether your browser had cached the page or image you have selected. If your browser did not need to get the page refreshed because it was cached, then RPT playback will EXACTLY mimic the behavior of your browser at recording time. That is why flushing your file cache is recommended as a step in starting your recording session.
From a high level, there are two ways Rational Performance Tester (RPT) will handle cookie data; the method is chooses is based on how the cookie data was captured in the original recording.
- Pre-existing cookies:
In this scenario, cookie data exists prior to the recording.
If you are already logged into local intranet site (Say in this example you would have used the internal IBM site) and perform a new recording,. The first request of the first page will have a cookie already set (as seen below).
GET / HTTP/1.1
Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg,
application/vnd.ms-excel, application/vnd.ms-powerpoint, */*
Accept-Encoding: gzip, deflate
User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET
CLR 1.1.4322; .NET CLR 2.0.50727)
Since this is pre-existing cookie, RPT has no knowledge of how the cookie obtained its original value. Hence at runtime, the cookie value in the Test will be the one used at Runtime. Potentially, this could be an issue if the cookie has an expiration date. To avoid this scenario always delete the cookie cache from the browser prior to recording.
- Acquired Cookies:
In this scenario cookie data is set during the recording.
If you have cleared the cookie cache prior to the recording, and perform another recording against the local intranet site, the cookie will be set during the recording. You can verify this by the presence of the ?Set-Cookie? response header. This indicates a cookie was set by the server during the recording (as seen below)
In this case, RPT knows how the cookie is set and will capture and correlate the new value at run-time. Unlike standard data correlation values, RPT does not color code the cookie values; the correlation is
done behind the scenes.