Optimizing a four-year-old MySQL database I developed an application with MySQL 5.1 back-end four years ago. After that, I only gave remote support a couple of times, but that too for application crashes, and not for database. The database is still running well. The customer takes the backup on decided schedules. I want to optimize the database as I think in these years many records have been deleted and many added.

How do I tune up the database and bring it into proper shape? What things need attention?
I want to optimize the database as I think in these years many records
  have been deleted and many added.


You have some other reason for wanting to fiddle with a database that is "running well"?

Good reasons might include:


The backups are getting unmanageably large
The customer has mentioned a specific area of performance they want improved


If you don't have a good reason, then my advice would be to do nothing