ALTER RESOURCE POOL

Purpose

The ALTER RESOURCE POOL statement is used to modify the properties of a resource pool, including UNIT, UNIT_NUM, and ZONE_LIST.

Limitations and considerations

• When using the ALTER RESOURCE POOL statement to modify resource pool properties, each statement can only modify one property at a time. If you need to modify two or more properties from UNIT, UNIT_NUM, and ZONE_LIST simultaneously, you need to execute multiple statements.

• OceanBase Database supports both homogeneous and heterogeneous zone modes for tenants. In homogeneous zone mode, the number of units in each zone of the tenant must be the same. In heterogeneous zone mode, the number of units in each zone of the tenant can be different, but a tenant can have at most two different unit_num values. When increasing or decreasing UNIT_NUM:

  • In heterogeneous zone mode, you can use the ALTER RESOURCE POOL statement to increase or decrease UNIT_NUM regardless of whether the resource pool is allocated to the tenant.

    Notice

    By default, existing tenants or upgraded tenants are in homogeneous zone mode. To enable heterogeneous zone mode, you need to set the zone_deploy_mode parameter to hetero. After modification, it is not supported to change it back to homo.

  • In homogeneous zone mode, if the resource pool is allocated to the tenant, you cannot use the ALTER RESOURCE POOL statement to modify it. Instead, you need to use the ALTER RESOURCE TENANT statement. For more information about the ALTER RESOURCE TENANT statement, see ALTER RESOURCE TENANT.

Privilege requirements

Only the root user of the sys tenant (root@sys) can modify a resource pool. Other tenants do not support modifying resource pools.

Syntax

ALTER RESOURCE POOL

ALTER RESOURCE POOL pool_name
      UNIT [=] unit_name
    | UNIT_NUM [=] unit_num [DELETE UNIT = (unit_id_list)]
    | ZONE_LIST [=] ('zone_name' [, 'zone_name' ...]);

Parameters

Examples

• You cannot modify multiple properties of a resource pool in a single statement. For example, the following statement attempts to modify the UNIT, UNIT_NUM, and ZONE properties of resource pool pool1, which will result in an error.

  obclient [oceanbase]> ALTER RESOURCE POOL pool1 UNIT='unit2', UNIT_NUM=1, ZONE_LIST=('zone1');
  ERROR 1235 (0A000): alter unit_num, resource_unit, zone_list in one cmd not supported
  

  Specifically, when decreasing UNIT_NUM, you can delete the specified unit.

  obclient [oceanbase]> ALTER RESOURCE POOL pool1 UNIT_NUM=1 DELETE UNIT = (1002);
  

• Change the resource specification used by resource pool pool1 to unit2.

  obclient [oceanbase]> ALTER RESOURCE POOL pool1 UNIT='unit2';
  

References

• View resource pools

• Modify resource pool properties