2022-11-11 myql Block Nested-Loop and Batched Key Access Joins

MySQL :: MySQL 5.7 Reference Manual :: 8.2.1.11 Block Nested-Loop and Batched Key Access Joins

8.2.1.11 Block Nested-Loop and Batched Key Access Joins

In MySQL, a Batched Key Access (BKA) Join algorithm is available that uses both index access to the joined table and a join buffer. The BKA algorithm supports inner join, outer join, and semijoin operations, including nested outer joins. Benefits of BKA include improved join performance due to more efficient table scanning. Also, the Block Nested-Loop (BNL) Join algorithm previously used only for inner joins is extended and can be employed for outer join a