On the application settings page of each APM application in the New Relic user interface (Left-hand column → “Settings” section → Application) there is a field for setting an “Application alias” for your application.
Changing the value of that field will change the name displayed in the UI for that application. However, as noted in the caption underneath the text field, setting a display alias does not change the actual name of the application. The actual name of the application is determined by the data reporting from the APM language agent (Java .NET, Node, Ruby, etc.) on your host(s) to New Relic.
Undoubtedly this functionality can be useful in some situations, but it can also lead to some confusion in some cases. This is especially true when a display alias is set for an application reporting with a generic, default name.
For example, the .NET agent ships with a generic name,
My Application, set in its configuration file. If the agent is installed and no other naming configuration is set, all applications monitored on that host will report to New Relic as “My Application”.
Admittedly, “My Application” is not a very useful name for an application. So, if you’ve just gotten the agent set up and reporting data for your development “user log-in” application, you may be tempted to simply set the display alias to “user-login-dev” in the UI and move on.
However, if you were to do that, you’d be putting yourself in the following situation:
Any other application that reports with the name “My Application”, on this host or any other, will have its data lumped in with (what looks like) your “user-login-dev” application in the UI.
This can cause data pollution in the “user-login-dev” application, since data from unknown applications could be reporting into this app.
This could also cause confusion for anyone installing the agent on another host for the first time, as they may be expecting to see a “My Application” app in the UI and not know it has been changed to “user-login-dev”.
Once data has reported to an application in the UI, it can’t be migrated to a different application. If you change the name reporting from your host, the data starts flowing into a new/different application in the UI. In this case, your new data would be disconnected from the historical data collected when the application was reporting under “My Application”.
For this reason, I advise that you use caution when setting a display alias for applications in the UI, and you should never set a display alias for applications reporting with an agent’s default name (like “My Application”).