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MySQL Replication  /  ...  /  Configuring Multi-Source Replication

2.5.1 Configuring Multi-Source Replication

A multi-source replication topology requires at least two sources and one replica configured. In these tutorials, we assume that you have two sources source1 and source2, and a replica replicahost. The replica replicates one database from each of the sources, db1 from source1 and db2 from source2.

Sources in a multi-source replication topology can be configured to use either GTID-based replication, or binary log position-based replication. See Section 2.3.4, “Setting Up Replication Using GTIDs” for how to configure a source using GTID-based replication. See Section 2.2.1, “Setting the Replication Source Configuration” for how to configure a source using file position based replication.

Replicas in a multi-source replication topology require TABLE repositories for the replica's connection metadata repository and applier metadata repository, which are the default in MySQL 8.0. Multi-source replication is not compatible with file repositories, and the FILE setting for the master_info_repository and relay_log_info_repository system variables is now deprecated.

You can modify an existing replica that is using FILE repositories for the replication applier metadata repositories to use TABLE repositories. To convert the existing repositories dynamically, first stop replication by using the mysql client to issue the STOP REPLICA | SLAVE statement on the replica. Then issue the following statements:

mysql> SET GLOBAL master_info_repository = 'TABLE';
mysql> SET GLOBAL relay_log_info_repository = 'TABLE';

Create a suitable user account on all the sources that the replica can use to connect. You can use the same account on all the sources, or a different account on each. If you create an account solely for the purposes of replication, that account needs only the REPLICATION SLAVE privilege. For example, to set up a new user, ted, that can connect from the replica replicahost, use the mysql client to issue these statements on each of the sources:

mysql> CREATE USER 'ted'@'replicahost' IDENTIFIED BY 'password';
mysql> GRANT REPLICATION SLAVE ON *.* TO 'ted'@'replicahost';

For more details, and important information on the default authentication plugin for new users from MySQL 8.0, see Section 2.2.3, “Creating a User for Replication”.