View locality

This topic describes how to view the replica types and distribution of tenants through the DBA_OB_TENANTS view.

For more information about the DBA_OB_TENANTS view, see DBA_OB_TENANTS.

Procedure

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

   obclient -h172.30.xxx.xxx -P2883 -uroot@sys#obdemo -pxxxx -A
   

2. Access the database named oceanbase.

   obclient>use oceanbase;
   

3. Query the types and distribution of replicas for tenants from the oceanbase.DBA_OB_TENANTS view.

   obclient> SELECT TENANT_ID,TENANT_NAME,TENANT_TYPE,PRIMARY_ZONE,LOCALITY FROM oceanbase.DBA_OB_TENANTS;
   +-----------+-------------+-------------+----------------------------------------+------------------------------------------------------------------+
   | TENANT_ID | TENANT_NAME | TENANT_TYPE | PRIMARY_ZONE                           | LOCALITY                                                         |
   +-----------+-------------+-------------+----------------------------------------+------------------------------------------------------------------+
   |         1 | sys         | SYS         | sa128_obv4_2;sa128_obv4_1,sa128_obv4_3 | FULL{1}@sa128_obv4_1, FULL{1}@sa128_obv4_2, FULL{1}@sa128_obv4_3 |
   |      1001 | META$1002   | META        | sa128_obv4_2;sa128_obv4_1,sa128_obv4_3 | FULL{1}@sa128_obv4_1, FULL{1}@sa128_obv4_2, FULL{1}@sa128_obv4_3 |
   |      1002 | midas0_3790 | USER        | sa128_obv4_2;sa128_obv4_1,sa128_obv4_3 | FULL{1}@sa128_obv4_1, FULL{1}@sa128_obv4_2, FULL{1}@sa128_obv4_3 |
   |      1003 | META$1004   | META        | sa128_obv4_1,sa128_obv4_2              | FULL{1}@sa128_obv4_1, FULL{1}@sa128_obv4_2                       |
   |      1004 | mq_t1       | USER        | sa128_obv4_1,sa128_obv4_2              | FULL{1}@sa128_obv4_1, FULL{1}@sa128_obv4_2                       |
   +-----------+-------------+-------------+----------------------------------------+------------------------------------------------------------------+
   5 rows in set
   

   Note

   The locality FULL{1}@sa128_obv4_1, FULL{1}@sa128_obv4_2 in the preceding example is for illustration only. In practice, ensure that the number of zones added can satisfy the majority principle.

The LOCALITY column in the DBA_OB_TENANTS view indicates the replica types and distribution of a tenant. Locality describes the replica types of a tenant and their distribution across zones in the cluster.

For example, for tenant mq_t1, LOCALITY = 'FULL{1}@sa128_obv4_1, FULL{1}@sa128_obv4_2' indicates that there is one full-featured replica in each of sa128_obv4_1 and sa128_obv4_2.

References

• Locality overview

• Modify locality

• Add replicas