Session: An Introduction to MySQL Indexes & Histograms
Nobody ever complains that the database is too fast. But tuning a database query can get tricky. You add one index and things go faster but adding a second one makes processing crawl. The MySQL optimizer uses historical information to develop a query plan and the two best known ways to augment that information are indexes and histograms. This session covers how indexes really work, how the optimizer evaluates those indices for processing, how secondary indexes piggy-back’ on primary indexes, and how to tell what index is really being used. And new in 8.0 are histograms but they may not fit your data. So if you want faster queries or just a better understanding of how MySQL works then this session is for you.