ADMIN [SET|SHOW|UNSET] BDR ROLE

Use ADMIN SET BDR ROLE to set the BDR role of the cluster. Currently, you can set the following BDR roles for a TiDB cluster: PRIMARY and SECONDARY. For more information about BDR roles, see DDL Synchronization in TiCDC Bidirectional Replication.
Use ADMIN SHOW BDR ROLE to show the BDR role of the cluster.
Use ADMIN UNSET BDR ROLE to unset the BDR role of the cluster.

Synopsis

By default, a TiDB cluster has no BDR role. Run the following command to show the BDR role of the cluster.

ADMIN SHOW BDR ROLE;

+------------+
| BDR_ROLE   |
+------------+
|            |
+------------+
1 row in set (0.01 sec)

Run the following command to set the BDR role to PRIMARY.

ADMIN SET BDR ROLE PRIMARY;

Query OK, 0 rows affected (0.01 sec)

ADMIN SHOW BDR ROLE;
+----------+
| BDR_ROLE |
+----------+
| primary  |
+----------+
1 row in set (0.00 sec)

Run the following command to unset the BDR role of the cluster.

ADMIN UNSET BDR ROLE;

Query OK, 0 rows affected (0.01 sec)

ADMIN SHOW BDR ROLE;
+----------+
| BDR_ROLE |
+----------+
|          |
+----------+
1 row in set (0.01 sec)

This statement is a TiDB extension to MySQL syntax.