How to make a Callback to update any record in the database?

Question

Android

I need to make it so that when a record is added to the database on the server, a notification comes in the application. I don’t want to use Firebase, since all records and user roles already exist and are configured in another database. How to implement it? I read about Service, but the tutorial has this line: "As per Android Developer team, you can't perform long-running operations in the background without notifying users.". Because of this, the status constantly hangs in the curtain that the application is running in the background, but I don’t need it.