To use inbound replication in MySQL HeatWave Service, the source and its network connection to the replica need this configuration.

• For an external source server, your VCN and local network must be configured to permit replication traffic between the DB system replica and the source. You can use Site-to-Site VPN, FastConnect, or OpenVPN Access Server for the connection.
  Note
  
  The source server must have a properly configured ingress seclist, VPN, or on-premise firewall to allow traffic from the entire subnet to which your DB system is attached, and not just the IP address of your DB system. This is because the IP address of the replication channel can change in some scenarios such as during upgrades.
• The minimum supported version of MySQL for a replication source is 5.7.9.
• The source cannot be running a higher version of MySQL than the DB system replica. The replica must be running the same version as, or a higher version of MySQL than, the source.
• If you intend to encrypt the communication between source and replica, the source must be configured to use SSL. See Server-side Configuration for Encrypted Connections.
• The source and the DB system replica must run with the same lower_case_table_names system variable value. See Initialization Variables.
• The source must use row-based binary logging, with the system variable binlog_format=ROW. This is the default in MySQL 8.0 and higher. Statement-based replication and mixed replication are not supported by MySQL HeatWave Service. See MySQL Reference Manual - binlog_format.
  Note
  
  It is recommended to enable GTID on the source, set the system variable gtid_mode to ON. See Enabling GTID Transactions Online. Even though binary log file position based replication is supported in MySQL HeatWave Service inbound replication, GTID-based replication is more robust.

  For MySQL source server prior to version 8.3.0, it is recommended to set binlog_transaction_dependency_tracking to WRITESET. This can increase the replication parallelism, and thus reduce replication lag.

• The replication user must be present on the source server with the required privileges. See Creating a Replication User On a Source Server.