The slides of my talk on B+Tree Indexes and InnoDB are now available for download. This slide was presented during Percona Live London 2011. You can download the slides from here. There are many other interesting and informative talks that were presented during Percona Live London 2011, and I think you should definitely check them out, if you haven't. They are available here.
The purpose of this post is to describe what covering indexes are and how they can be used to improve the performance of queries. People mostly use indexes to filter or sort the results but not much thought is given to actually reduce the disk reads by using proper indexes. So I will show you how to reduce disk reads and hence improve the performance of queries by utilizing indexes properly.