Primary-replica replication is commonly used for disaster recovery, where a replica server at a remote location maintains a real-time copy of the primary server's data. This allows the replica to take over in case the primary server fails.

CHAR and VARCHAR are string datatypes in MySQL. CHAR is for fixed-length strings, and VARCHAR is for variable-length strings. BLOB is a binary large object, and INT is a numeric datatype.

HeatWave Cluster is specifically designed to optimize complex analytical queries. It accelerates query performance by executing these queries in memory and in parallel, making it ideal for real-time analytics on large datasets.

MySQL Router is responsible for routing client connections to available and healthy nodes in the MySQL InnoDB Cluster. It helps ensure high availability by routing traffic to active servers in case of failure.

Normalization reduces data redundancy and ensures data integrity by organizing data into related tables. This leads to better data consistency across the database.