In this first entry in a multipart series on indexes, I will cover the most important index type in MySQL, B-Tree Indexes. Applying indexes of any type in MySQL is nuanced task – they are used to speed up the performance of our search queries at the expense of having to be maintained when data is changed in the table. This in turn slows down INSERT, DELETE statements (though typically an index will also help with DELETE operations because the rows to be deleted do have to be located.) UPDATE operations may or may not be affected depending on whether you