Please consider going through Andy Pavlo's superb video courses on building databases. http://www.cs.cmu.edu/~pavlo/ http://www.cs.cmu.edu/~pavlo/ He discusse

Please consider going through Andy Pavlo's superb video courses on building databases. http://www.cs.cmu.edu/~pavlo/ http://www.cs.cmu.edu/~pavlo/ He discusses many common pitfalls and architectural decisions that impact database quality and performance, including map and why it's bad.