User action metrics

For web applications, Dynatrace calculates the following user action metrics.

Milestone metrics

Milestone metrics represent events that occur at a specific point in time during a user action. However, they are measured in (m)sec, because they are calculated relative to the user action start time. In other words, user action start time serves as a reference point from which the time for the milestone metrics is measured. A value for example of 47msec for Navigation start indicates that this event occurred 47msec after the action start time.

Speed Index and Visually Complete are only available on browsers that support mutationobservers. This includes the following browsers:

  • Microsoft Internet Explorer 11
  • Microsoft Edge 15 or later
  • Firefox 57 or later
  • Google Chrome 61 or later

Phase metrics

As opposed to milestone metrics, phase metrics imply a duration.

Metric Description Applicable to
Blocking The time between the moment the browser realizes it needs to download a resource and the time that it actually starts downloading the resource. This includes the time spent on waiting for a free TCP socket, the time required for generating disk cache entries and the time spent in proxy negotiation. Load actions
Application cache The time spent checking any relevant application caches. It includes the time before the connection to the server is established. Load actions
DNS lookup The time spent on the domain name lookup for the current document. Load actions
TCP connect The time spent on establishing the connection to the server including SSL. Load actions
Secure connect The time spent on making the established connection to the server secure. This includes the SSL handshake and SOCKS. Load actions
Request The time spent on requesting the current document from the server until the first byte is received. Load actions
Response The time spent on receiving the response. Load actions
Processing The time between DOM loading and Load event start. Load actions
OnLoad The time spent on processing the load event. Load actions
OnDOMContentLoaded The time spent on executing onDomContentLoaded handlers. Load actions
Response end The elapsed time from when the first byte of the server response is received until either when the last byte of the current document of the response is received or when the response completes, whichever happens first. XHR actions Load actions
Redirect time The time spent on subsequent HTTP requests. Load actions

Key performance metrics

From the metrics listed above, Dynatrace has specified some as key. Key performance metrics enable you to select the ideal user experience metric for each of your applications. These key metrics provide you with valuable performance insights that promote success in your digital business. The key performance metrics include:

  • User action duration
  • Visually complete
  • Speed index
  • DOM interactive
  • Load event end
  • Load event start
  • HTML downloaded
  • Time to first byte

Dynatrace allows you to choose the right performance metric for each application condition.