What are the possible use cases for MySQL Router?

Some of the applications for MySQL Router include:

1. Distributed Deployment: MySQL Router can be used in scenarios requiring distributed deployment, routing client requests to different instances of MySQL to achieve load balancing and fault recovery.
2. Master-slave replication: MySQL Router can act as an intermediary layer in master-slave replication architecture, responsible for routing write operations to the master node and read operations to the slave node, achieving read-write separation and improving system performance.
3. Multi-tenant system: MySQL Router can route client requests to different database instances based on different tenants, achieving isolation and management of multi-tenant systems.
4. Database migration: MySQL Router can serve as an intermediary layer during the database migration process, routing requests from the original database to the new database instance for a smooth transition with zero downtime.
5. Data Sharding: MySQL Router can act as a middle layer in a data sharding architecture, routing client requests to different data shards, enabling horizontal splitting and scaling of the database.

In conclusion, MySQL Router can serve as an intermediary in various scenarios, achieving functions such as load balancing, fault recovery, read-write separation, multi-tenant management, database migration, and data sharding.