Modify attributes of a resource pool

You can modify the UNIT, UNIT_NUM, and ZONE_LIST parameters for a resource pool. This topic describes the modification procedure.

You can use the ALTER RESOURCE POOL statement to modify attributes of a resource pool.

You can scale up or down a tenant by modifying the attributes of its resource pool. For example, you can increase the value of UNIT_NUM to increase the number of nodes in each zone to scale out the tenant.

Procedure

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

   obclient -h172.30.xx.xx -P2883 -uroot@sys#cluster -p**** -A
   

2. Access the database named oceanbase.

   obclient(root@sys)[(none)]> USE oceanbase;
   

3. Query the DBA_OB_RESOURCE_POOLS view for the configuration information about resource pools.

   To query the configuration information about the resource pool named mq_pool_02, execute the following statement:

   obclient(root@sys)[oceanbase]> SELECT * FROM DBA_OB_RESOURCE_POOLS WHERE NAME = 'mq_pool_02';
   

   Query result:

   +------------------+------------+-----------+----------------------------+----------------------------+------------+----------------+-------------+--------------+
   | RESOURCE_POOL_ID | NAME       | TENANT_ID | CREATE_TIME                | MODIFY_TIME                | UNIT_COUNT | UNIT_CONFIG_ID | ZONE_LIST   | REPLICA_TYPE |
   +------------------+------------+-----------+----------------------------+----------------------------+------------+----------------+-------------+--------------+
   |             1026 | mq_pool_02 |      NULL | 2023-01-10 23:54:24.177685 | 2023-01-10 23:54:24.177685 |          1 |           1020 | zone1;zone2 | FULL         |
   +------------------+------------+-----------+----------------------------+----------------------------+------------+----------------+-------------+--------------+
   1 row in set
   

   For more information about the DBA_OB_RESOURCE_POOLS view, see DBA_OB_RESOURCE_POOLS.

4. Execute the ALTER RESOURCE POOL statement to modify the configurations of the resource pool.

   Notice

   • This statement modifies only one attribute at a time. To modify two or more of the UNIT, UNIT_NUM, and ZONE_LIST attributes, execute this statement multiple times.
   • When you modify the ZONE_LIST attribute, you can add or remove only one zone at a time.

   The syntax is as follows:

   ALTER RESOURCE POOL pool_name
       UNIT [=] unit_name,
       UNIT_NUM [=] unit_num,
       ZONE_LIST [=] ('zone' [, 'zone' ...]);
   

   The parameters are described as follows:

   • pool_name: the name of the resource pool.

   • UNIT: the unit config for the resource pool.

   • UNIT_NUM: the number of resource units. When you add resource units, make sure that the value of UNIT_NUM does not exceed the number of OBServer nodes in each zone.

     Notice

     The current version supports heterogeneous zone mode. When modifying UNIT_NUM:

     • In homogeneous zone mode, if the resource pool is already used by a tenant, you cannot modify it with the ALTER RESOURCE POOL statement. You need to use the ALTER RESOURCE TENANT statement instead.
     • In heterogeneous zone mode, even if the resource pool is already used by a tenant, you can modify it with the ALTER RESOURCE POOL statement. However, when making modifications, a tenant's resource pools can have at most two different UNIT_NUM values.

       For example, if a tenant has three resource pools: pool1, pool2, and pool3, with unit_num values of 2, 4, and 4 respectively, and you change pool3's unit_num to 1, the system will report a More than two distinct unit_num in a single tenant not allowed error.

     For more information about the ALTER RESOURCE POOL statement, see ALTER RESOURCE POOL.

     For more information about the ALTER RESOURCE TENANT statement, see ALTER RESOURCE TENANT.

   • ZONE_LIST: the distribution of the resource pool in zones.

   Here are some examples:

   Homogeneous zone mode

   Heterogeneous zone mode

   • The resource pool is not allocated to any tenant

     To set the unit config to 'S2_unit_config', the number of resource units to 3, and ZONE_LIST to 'zone1','zone2','zone3' for the resource pool mq_pool_02, execute the following statements:

     obclient(root@sys)[oceanbase]> ALTER RESOURCE POOL mq_pool_02 UNIT='S2_unit_config';
     

     obclient(root@sys)[oceanbase]> ALTER RESOURCE POOL mq_pool_02 UNIT_NUM=3;
     

     obclient(root@sys)[oceanbase]> ALTER RESOURCE POOL mq_pool_02 ZONE_LIST=('zone1','zone2','zone3');
     

   • The resource pool is allocated to a tenant

     In homogeneous zone mode, when modifying the resource pool configuration for a tenant that has already been assigned the resource pool, you must use the ALTER RESOURCE TENANT statement to modify UNIT_NUM.

     To set the unit config to 'S2_unit_config', the number of resource units to 3, and ZONE_LIST to 'zone1','zone2','zone3' for the resource pool mq_pool_02, execute the following statements:

     obclient(root@sys)[oceanbase]> ALTER RESOURCE POOL mq_pool_02 UNIT='S2_unit_config';
     

     obclient(root@sys)[oceanbase]> ALTER RESOURCE TENANT mq_t2 UNIT_NUM=3;
     

     obclient(root@sys)[oceanbase]> ALTER RESOURCE POOL mq_pool_02 ZONE_LIST=('zone1','zone2','zone3');
     

   Notice

   By default, existing tenants and upgraded tenants use homogeneous zone mode. To enable heterogeneous zone mode, set the tenant-level parameter zone_deploy_mode to hetero. After the change, you cannot revert to homo (homogeneous zone mode).

   To set the unit config to 'S2_unit_config', the number of resource units to 3, and ZONE_LIST to 'zone1','zone2','zone3' for the resource pool mq_pool_02, execute the following statements:

   obclient(root@sys)[oceanbase]> ALTER RESOURCE POOL mq_pool_02 UNIT='S2_unit_config';
   

   obclient(root@sys)[oceanbase]> ALTER RESOURCE POOL mq_pool_02 UNIT_NUM=3;
   

   obclient(root@sys)[oceanbase]> ALTER RESOURCE TENANT mq_t2 UNIT_NUM=3;
   

   obclient(root@sys)[oceanbase]> ALTER RESOURCE POOL mq_pool_02 ZONE_LIST=('zone1','zone2','zone3');
   

5. Query the DBA_OB_RESOURCE_POOLS view to verify the modification result.

   The query result shows that the values of UNIT_COUNT, UNIT_CONFIG_ID, and ZONE_LIST are updated.

   obclient(root@sys)[oceanbase]> SELECT * FROM DBA_OB_RESOURCE_POOLS WHERE NAME = 'mq_pool_02';
   

   The query result is as follows:

   +------------------+------------+-----------+----------------------------+----------------------------+------------+----------------+-------------------+--------------+
   | RESOURCE_POOL_ID | NAME       | TENANT_ID | CREATE_TIME                | MODIFY_TIME                | UNIT_COUNT | UNIT_CONFIG_ID | ZONE_LIST         | REPLICA_TYPE |
   +------------------+------------+-----------+----------------------------+----------------------------+------------+----------------+-------------------+--------------+
   |             1026 | mq_pool_02 |      NULL | 2023-01-10 23:54:24.177685 | 2023-01-10 23:56:04.961771 |          2 |           1021 | zone1;zone2;zone3 | FULL         |
   +------------------+------------+-----------+----------------------------+----------------------------+------------+----------------+-------------------+--------------+
   1 row in set