Advanced MySQL 8

Changing the group mode

We can switch from single-primary to multi primary and vice versa. Use the grop_replication_switch_to_single_primary_mode() UDF to change a group running in multi-primary mode to single_primary_mode:

mysql> SELECT group_replication_switch_to_single_primary_mode(Optional UUID);

If we do not pass any argument, the election of the primary will happen based on weights assigned to the members or the UUID lexicographic order. And if you want a specific member to be primary, then you need to specify the UUID of the member.

Use the group_replication_switch_to_multi_primary_mode() UDF to change a group running in single-primary mode to multi_primary_mode by issuing the following command:

mysql> SELECT group_replicaiton_switch_to_multi_primary_mode() ...