This session was presented at RivieraJUG, Nice, France on September 2022. Nobody complains that the database is too fast. But when things slow down, the complaints come quickly. The two most popular approaches to speeding up queries are indexes and histograms. But there are so many options and types on indexes that it can get confusing. Histograms are fairly new to MySQL but they do not work for all types of data. This talk covers how indexes and histograms work and shows you how to test just how effective they are so you can measure the performance of your queries.