I have written a
new post on the MySQL blog about the hypergraph optimizer, which is now available in MySQL 9.7 Community Edition.
The post gives a high-level technical overview of what is different from the classic join optimizer, why it can produce better plans for some multi-table queries, and where it is most useful to try. It also includes early benchmark results and some caveats, since the feature is still evolving and remains off by default.