Not sure how "db security" factors in, but yes it's likely a premature optimization for many users, but these three are some of the most frequently abused RDBMS

Not sure how "db security" factors in, but yes it's likely a premature optimization for many users, but these three are some of the most frequently abused RDBMS items I see on a regular basis. And often the major limiting factor in the client's performance. While it is "raw performance of one part of the system", it's also the hardest aspect of a system to scale properly. Not doing these three things can often get a user months or years further down the line without having to worry about it at all.