The read replica load balancer and the associated DB system has certain limitations.

• Currently the read replica load balancer supports up to 8 Gbps bandwidth to access the read replicas.
• The account name that you use to connect to the read replica consists of the user name and client host name. If you connect to the read replicas using the read replica load balancer, you cannot use the client host name or host based access control rules. In this case, the account name must consist of the user name only. See Connection Verification.
• You cannot configure the read replica load balancer as a backend server of an Oracle Cloud Infrastructure Network Load Balancer.
• During outbound replication, you cannot configure a read replica as the source; you can configure only a DB system as the source.
• Prior to MySQL 8.3.0-u2, you cannot create read replicas on a DB system with HeatWave Lakehouse enabled.
• You cannot create read replicas on an IPv6 enabled subnet. The DB system and read replicas must be created on an IPv4-only subnet.
• The read replica load balancer has a maximum limit of about 21,500 active connections to the read replicas. This restricts the maximum number of concurrent active connections to the read replica load balancer to about 21,500.
• Each TCP connection has an idle timeout of 8 hours. If the connection has no traffic between the client and server after the timeout, it is removed from the read replica load balancer and the client needs to reconnect.
• Read replica is not supported on an Always Free DB system.