20.2.1.4 Launching Group Replication

It is first necessary to ensure that the Group Replication plugin is installed on server s1. If you used plugin_load_add='group_replication.so' in the option file then the Group Replication plugin is already installed, and you can proceed to the next step. Otherwise, you must install the plugin manually; to do this, connect to the server using the mysql client, and issue the SQL statement shown here:

mysql> INSTALL PLUGIN group_replication SONAME 'group_replication.so';

Important

The mysql.session user must exist before you can load Group Replication. mysql.session was added in MySQL version 8.0.2. If your data dictionary was initialized using an earlier version you must perform the MySQL upgrade procedure (see Chapter 3, Upgrading MySQL). If the upgrade is not run, Group Replication fails to start with the error message There was an error when trying to access the server with user: mysql.session@localhost. Make sure the user is present in the server and that mysql_upgrade was ran after a server update.

To check that the plugin was installed successfully, issue SHOW PLUGINS; and check the output. It should show something like this:

mysql> SHOW PLUGINS;
+----------------------------+----------+--------------------+----------------------+-------------+
| Name                       | Status   | Type               | Library              | License     |
+----------------------------+----------+--------------------+----------------------+-------------+
| binlog                     | ACTIVE   | STORAGE ENGINE     | NULL                 | PROPRIETARY |

(...)

| group_replication          | ACTIVE   | GROUP REPLICATION  | group_replication.so | PROPRIETARY |
+----------------------------+----------+--------------------+----------------------+-------------+