View locality

This topic describes how to query for the types and distribution of replicas for tenants from the DBA_OB_TENANTS view.

For more information about the DBA_OB_TENANTS view, see oceanbase.DBA_OB_TENANTS.

Procedure

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

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

2. Access the database named oceanbase.

   obclient>use oceanbase;
   

3. Query for 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 in the preceding example is FULL{1}@sa128_obv4_1, FULL{1}@sa128_obv4_2. When you add zones, make sure that the majority principle is met.

The LOCALITY field in the DBA_OB_TENANTS table specifies the replica types and distribution tenants cross zones in the cluster.

For example, LOCALITY = 'FULL{1}@sa128_obv4_1, FULL{1}@sa128_obv4_2' for the mq_t1 tenant indicates that the tenant has one full-featured replica in both sa128_obv4_1 and sa128_obv4_2.

More information

• Locality

• Modify locality

• Add replicas