reset face recognition training data?

[pbhj at alicious.com]

I notice there's an option to reset face recognition training data, I've 
been using Digikam for several years is there any benefit in resetting 
this data? Presumably it then uses recognised faces to "prime the pump", 
or would I then be starting again from scratch? What will it keep (face 
tags) and what gets discarded?

Perhaps I should inspect the recognition.db files to see if there's 
anything amiss?

Thanks for any suggestions.

[Why do I want to do this? Basically to try and optimise the recognition 
process as it appears to be very resource intensive at the moment.]