MySQL Router Release Notes
MySQL Router supports Read-Write splitting. This configuration enables you to direct all read traffic to read-only instances, and all write traffic to read-write instances.
Read-write instances are primaries or sources. Read-only instances are secondaries in an InnoDB Cluster or the primary or secondary instances in a Replica Cluster.
MySQL Router classifies each query as read or write and directs it to
the appropriate backend. It is also possible to manually, or
programmatically, specify the type of query using ROUTER
SET or query_attributes.
Note
Each client session can communicate with one read_write and one read_only destination.