What is the IBM i DG8SVCPRF used for?
When an application requests a DataGate job on the IBM i, the ASNA DG8SVC initiates that job through an ASNA DG8_START job. DG8_START jobs run under the DG8SVCPRF user profile. Once DG8_START gets user credentials from the DataGate client, it adopts authority of the incoming user profile and then submits a DG8_NET job for the application. DG8_START then fades back into the background awaiting a another application request. Note that prior to DataGate 16.x, DG8_START jobs were spun up on demand; with DataGate 16.x three (by default) DG8_START jobs persist. (See this article for details on DataGate IBM i jobs).
Anytime you have issues with ASNA DataGate, taking a look at DG8SVCPRF's spool file is a good place to start.