Which system to choose for monitoring and subsequent optimization of the database?

Question

MySQL

Good afternoon.
It is necessary to develop a system for monitoring performance and subsequent optimization of the database.
What is:
A system that processes various data and runs on a separate server. DB - MySQL, most InnoDB tables, the number of records in the tables is from 1 million to 50 million, in the future the volume will grow. OS - Ubuntu 12.04.
What you need:
A system that will monitor the state of the database, tables, and if performance drops, somehow notify.
It is necessary to find algorithms, methods and ways of monitoring.

Answer 1

Watch the presentation Finding bottlenecks in production...
Based on it, you can determine what parameters should be monitored.