There are substantial improvements in the Optimizer in MySQL 8.0. Most noticeably, we have added support for advanced SQL features like common table expressions, windowing functions and grouping() function. We also made DBAs' lives easier with invisible indexes, and additional hints that can be used together with the query rewrite plugin.
On the performance side, cost model changes will make a huge impact. We have made JSON support even more powerful by adding JSON table function, aggregation functions and more. Come and learn about new features in MySQL 8.0!
I have 20 years experience in the database field. I am currently working as director at Oracle, heading the MySQL optimizer and executor team. Previously, I held various positions both as product manager and engineering manager at Sun Microsystems.