One time I tried to change a column name in a production database. I learned that when you change a column name, mysql doesn't just change a string somewhere, i

One time I tried to change a column name in a production database. I learned that when you change a column name, mysql doesn't just change a string somewhere, it creates a new table and copies all the values from the old table into the new one and when that table has millions of rows in it, it really slows down your production server.