To use inbound replication in 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 read-write endpoint IP address of the DB system. Any DB system created before July 2024 needs to be updated (either manually or through the automated maintenance), otherwise, it uses a different IP address in the subnet which can change in some scenarios such as switchover, failover, and 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 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 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.