https://www.slideshare.net/olavsa/presentations
https://www.slideshare.net/oysteing/presentations
https://dev.mysql.com/doc/refman/5.7/en/cost-model.html
http://www.unofficialmysqlguide.com/cost-based-optimization.html
https://www.slideshare.net/oysteing/how-to-analyze-and-tune-sql-queries-for-better-performance-webinar
https://www.slideshare.net/oysteing/using-optimizer-hints-to-improve-mysql-query-performance
https://stackoverflow.com/questions/45551920/why-the-cost-does-not-include-the-cpu-cost-for-rows-that-are-not-filtered-out-in
https://www.percona.com/live/17/sites/default/files/slides/MySQL8.0OptimizerGuide-OracleDeck.pdf
https://www.slideshare.net/olavsa/mysql-optimizer-cost-model
http://mysql.taobao.org/monthly/2016/07/02/