Enable arbitration service for a tenant

You can enable the arbitration service for a tenant when you create the tenant. For more information, see Create a tenant. If the arbitration service is not enabled for a tenant, you can enable it after the tenant is created. This topic describes how to enable the arbitration service for an existing tenant.

Prerequisites

• Make sure that the arbitration service is deployed in the current cluster. For more information, see Deploy an OceanBase cluster with two replicas and the arbitration service.

• Before you enable the arbitration service, make sure that the Locality of the tenant to be enabled is 2F or 4F. At present, the arbitration service can be enabled only for tenants whose Locality is 2F or 4F.

  Note

  The arbitration service can be enabled only for tenants whose Locality contains two F replicas. The number of R replicas in the Locality of a tenant does not affect whether the arbitration service can be enabled. For example, the arbitration service can be enabled for a tenant whose Locality is F@z1,F@z2 or F@z1,F@z2,R@z3.

Procedure

1. Log in to the sys tenant of the cluster as the root user.

   The following example shows how to connect to the database. Please replace the placeholders with actual values in your environment.

   obclient -h10.xx.xx.xx -P2883 -uroot@sys#obdemo -p***** -A
   

   For more information about how to connect to the database, see Overview of database connections (MySQL mode) and Overview of database connections (Oracle mode).

2. Execute the following command to view the connectivity status of nodes in the cluster.

   obclient(root@sys)[oceanbase]> SELECT * FROM oceanbase.GV$OB_ARBITRATION_SERVICE_STATUS;
   

   The query result is as follows.

   +----------------+----------+-----------------------------+----------+
   | SVR_IP         | SVR_PORT | ARBITRATION_SERVICE_ADDRESS | STATUS   |
   +----------------+----------+-----------------------------+----------+
   | xx.xx.xx.197   |     2882 | xx.xx.xx.192:2882           | ACTIVE   |
   | xx.xx.xx.194   |     2882 | xx.xx.xx.192:2882           | ACTIVE   |
   +----------------+----------+-----------------------------+----------+
   2 rows in set
   

   The value of the STATUS column indicates the connectivity status of a node with the arbitration service:

   • ACTIVE: indicates that the arbitration service can communicate with the node. The arbitration service can be enabled for a tenant only when all nodes are in the ACTIVE state.
   • INACTIVE: indicates that the arbitration service cannot communicate with the node. The arbitration service cannot be enabled for the tenant. Check the network connectivity between the node and the arbitration service.

3. Execute the following command to view the status of the arbitration service for the tenant.

   obclient(root@sys)[oceanbase]> SELECT * FROM oceanbase.DBA_OB_TENANTS WHERE tenant_name = 'oracle001'\G
   

   The query result is as follows.

   *************************** 1. row ***************************
                    TENANT_ID: 1004
                  TENANT_NAME: oracle001
                  TENANT_TYPE: USER
                  CREATE_TIME: 2026-01-26 19:40:21.457857
                  MODIFY_TIME: 2026-01-27 13:51:47.053502
                 PRIMARY_ZONE: zone1;zone2
                     LOCALITY: FULL{1}@zone1, FULL{1}@zone2
            PREVIOUS_LOCALITY: NULL
           COMPATIBILITY_MODE: ORACLE
                       STATUS: NORMAL
                IN_RECYCLEBIN: NO
                       LOCKED: NO
                  TENANT_ROLE: PRIMARY
            SWITCHOVER_STATUS: NORMAL
             SWITCHOVER_EPOCH: 0
                     SYNC_SCN: 1687845116605766616
               REPLAYABLE_SCN: 1687845116605766616
                 READABLE_SCN: 1687845116605766616
           RECOVERY_UNTIL_SCN: 4611686018427387903
                     LOG_MODE: NOARCHIVELOG
   ARBITRATION_SERVICE_STATUS: DISABLED
                     UNIT_NUM: 1
           ZONE_UNIT_NUM_LIST: zone1:1,zone2:1
                   COMPATIBLE: 4.6.0
                    MAX_LS_ID: 1002
            RESTORE_DATA_MODE: NORMAL
            FLASHBACK_LOG_SCN: NULL
                      COMMENT:
   1 row in set
   

   The arbitration service of a tenant can be in one of the following states:

   • ENABLED: indicates that the arbitration service is enabled for the tenant.

   • DISABLED: indicates that the arbitration service is disabled for the tenant.

   • ENABLING: indicates that the arbitration service is being enabled for the tenant.

   • DISABLING: indicates that the arbitration service is being disabled for the tenant.

   The query result shows that the ARBITRATION_SERVICE_STATUS column is DISABLED, which indicates that the arbitration service is disabled for the tenant.

   For more information about the DBA_OB_TENANTS view, see DBA_OB_TENANTS.

4. Execute the following command to enable the arbitration service for the tenant.

   The statement is as follows:

   ALTER TENANT tenant_name [SET] ENABLE_ARBITRATION_SERVICE = true;
   

   In this statement, tenant_name specifies the name of the tenant for which you want to enable the arbitration service, and SET is an optional keyword.

   The following example shows how to enable the arbitration service for the oracle001 tenant.

   obclient(root@sys)[oceanbase]> ALTER TENANT oracle001 ENABLE_ARBITRATION_SERVICE = true;
   

5. After the command is executed, query the DBA_OB_TENANTS view again to confirm whether the arbitration service is enabled for the tenant.

   obclient(root@sys)[oceanbase]> SELECT * FROM oceanbase.DBA_OB_TENANTS WHERE tenant_name = 'oracle001'\G
   

   The query result is as follows.

   *************************** 1. row ***************************
                    TENANT_ID: 1004
                  TENANT_NAME: oracle001
                  TENANT_TYPE: USER
                  CREATE_TIME: 2026-01-26 19:40:21.457857
                  MODIFY_TIME: 2026-01-27 13:51:47.053502
                 PRIMARY_ZONE: zone1;zone2
                     LOCALITY: FULL{1}@zone1, FULL{1}@zone2
            PREVIOUS_LOCALITY: NULL
           COMPATIBILITY_MODE: ORACLE
                       STATUS: NORMAL
                IN_RECYCLEBIN: NO
                       LOCKED: NO
                  TENANT_ROLE: PRIMARY
            SWITCHOVER_STATUS: NORMAL
             SWITCHOVER_EPOCH: 0
                     SYNC_SCN: 1687845116605766616
               REPLAYABLE_SCN: 1687845116605766616
                 READABLE_SCN: 1687845116605766616
           RECOVERY_UNTIL_SCN: 4611686018427387903
                     LOG_MODE: NOARCHIVELOG
   ARBITRATION_SERVICE_STATUS: ENABLED
                     UNIT_NUM: 1
           ZONE_UNIT_NUM_LIST: zone1:1,zone2:1
                   COMPATIBLE: 4.6.0
                    MAX_LS_ID: 1002
            RESTORE_DATA_MODE: NORMAL
            FLASHBACK_LOG_SCN: NULL
                      COMMENT:
   1 row in set
   

   The query result shows that the ARBITRATION_SERVICE_STATUS column is ENABLED, which indicates that the arbitration service is enabled for the tenant.

6. After the arbitration service is enabled, some log streams of the tenant may still lack arbitration members. These log streams cannot be upgraded or downgraded. You can perform the following steps to confirm this.

   When the arbitration service is enabled for a tenant, all log streams created at that time can use the arbitration service. However, log streams created after the arbitration service is enabled may lack arbitration members. This is because the creation of log streams is not strictly enforced, and the arbitration members may not be created successfully. Therefore, you can use the following statement to check whether all log streams of the tenant have arbitration members.

   The statement is as follows:

   (SELECT distinct ls_id FROM GV$OB_LOG_STAT WHERE tenant_id = tenantid) EXCEPT
   (SELECT ls_id FROM GV$OB_LOG_STAT WHERE tenant_id = tenantid AND role = 'LEADER' AND arbitration_member = 'arb_server_ip:arb_server_port');
   

   The parameters are described as follows:

   • tenantid: specifies the tenant ID of the tenant for which you want to enable the arbitration service.

   • arb_server_ip: specifies the IP address of the arbitration service.

   • arb_server_port: specifies the RPC port of the arbitration service. The default value is 2882.

   The following example shows how to execute the statement.

   obclient(root@sys)[oceanbase]> (SELECT distinct ls_id FROM GV$OB_LOG_STAT WHERE tenant_id = 1004) EXCEPT
   (SELECT ls_id FROM GV$OB_LOG_STAT where tenant_id = 1004 and role = 'LEADER' and arbitration_member = '100.xx.xx.xx:2882');
   

   If the query result is empty, all log streams have arbitration members, and the arbitration service is available. If the query result is not empty, the Root Service will automatically add arbitration members to these log streams. You can query the CDB_OB_LS_ARB_REPLICA_TASKS view to check whether there are ongoing tasks for adding arbitration members. If such tasks exist and are ongoing, wait for them to complete.

   After the tasks for adding arbitration members are completed, you can query the CDB_OB_LS_ARB_REPLICA_TASK_HISTORY view to check the task results. If the tasks are successful, the log streams have arbitration members, and the arbitration service is available. If the tasks fail, contact OceanBase support for assistance.

   For more information about the fields in the GV$OB_LOG_STAT view, see GV$OB_LOG_STAT.

References

For more information about the arbitration service, see the following topics:

• Deploy an OceanBase cluster with two replicas and an arbitration service

• Disable the arbitration service for a tenant

• Modify the degradation timeout

• Replace the arbitration service for a cluster

• Remove the arbitration service for a cluster