Modify UNIT_NUM

You can also increase the UNIT_NUM value of the resource pool to scale out a tenant. At present, you cannot decrease the UNIT_NUM value for the resource pool to scale in a tenant.

Prerequisites

Before you perform a scale-out operation on a tenant, you must perform the following steps:

• If the tenant is deleted, delete the resource pool of the tenant to release resources. Resources in an idle resource pool are also considered occupied resources.

  For more information about how to delete a resource pool, see Delete a resource pool.

• View the allocation of resources in the cluster to understand resource usage.

  For more information about how to view the total amount of resources and the resource allocation on OBServer nodes, see View the resource information about a cluster.

  Notice

  When you increase the UNIT_NUM value for a resource pool, ensure that the new UNIT_NUM value is smaller than or equal to the number of available OBServer nodes in each zone.

Modify the UNIT_NUM parameter of a tenant by using SQL statements

You can increase the value of the UNIT_NUM parameter to scale out a tenant.

Background

Assume that you have a cluster that has three zones, which are z1, z2, and z3, and each zone has three OBServer nodes. Create a user tenant named MySQL in the cluster. The following code shows the resource distribution of the tenant:

obclient> CREATE RESOURCE UNIT unit1 MAX_CPU 6, MIN_CPU 6, MEMORY_SIZE '36G', MAX_IOPS 1024, MIN_IOPS 1024, IOPS_WEIGHT=0, LOG_DISK_SIZE '2G';

obclient> CREATE RESOURCE POOL pool1 UNIT 'unit1', UNIT_NUM 1, ZONE_LIST ('z1','z2','z3');

obclient> CREATE TENANT MySQL resource_pool_list=('pool1');

Increase the value of the UNIT_NUM parameter

When the business volume increases, one resource unit in each zone is insufficient. In this case, you must increase the value of UNIT_NUM to improve the service capabilities of the tenant to meet increasing business needs.

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

2. Execute the following statement to go to the database named oceanbase:

   obclient>USE oceanbase;
   

3. Execute the following statement to query the resource configurations of the current tenant.

   obclient> SELECT a.TENANT_NAME, b.RESOURCE_POOL_ID,b.NAME resource_pool_name,b.UNIT_CONFIG_ID,b. UNIT_COUNT FROM oceanbase.DBA_OB_TENANTS a,oceanbase.DBA_OB_RESOURCE_POOLS b WHERE b.TENANT_ID=a.TENANT_ID;
   +-------------+------------------+--------------------+----------------+------------+
   | TENANT_NAME | RESOURCE_POOL_ID | resource_pool_name | UNIT_CONFIG_ID | UNIT_COUNT |
   +-------------+------------------+--------------------+----------------+------------+
   | sys         |                1 | sys_pool           |              1 |          1 |
   | tenant1     |             1001 | pool1              |           1001 |          2 |
   | Oracle      |             1002 | pool002            |           1002 |          1 |
   +-------------+------------------+--------------------+----------------+------------+
   3 rows in set
   
   obclient> SELECT * FROM oceanbase.DBA_OB_UNIT_CONFIGS WHERE UNIT_CONFIG_ID='1001';
   +----------------+-------+---------+---------+-------------+---------------+----------+----------+-------------+
   | UNIT_CONFIG_ID | NAME  | MAX_CPU | MIN_CPU | MEMORY_SIZE | LOG_DISK_SIZE | MAX_IOPS | MIN_IOPS | IOPS_WEIGHT |
   +----------------+-------+---------+---------+-------------+---------------+----------+----------+-------------+
   |           1001 | unit1 |       6 |       6 | 38654705664 |    2147483648 |     1024 |     1024 |           0 |
   +----------------+-------+---------+---------+-------------+---------------+----------+----------+-------------+
   1 row in set
   

   UNIT_COUNT indicates the number of resource units (UNIT_NUM) allocated to the current tenant.

4. Execute the following statement to increase the value of UNIT_NUM.

obclient>ALTER RESOURCE TENANT MySQL UNIT_NUM = 2;

After the statement is executed, the system adds a resource unit to each zone.

More information

When you scale out a tenant, you can query the following internal tables or views for resource information about the tenant:

• oceanbase.DBA_OB_UNIT_CONFIGS

  The DBA_OB_UNIT_CONFIGS view displays the unit_config information of all tenants in the current cluster.

  Example:

  obclient> SELECT * FROM oceanbase.DBA_OB_UNIT_CONFIGS;
  +----------------+-----------------+---------+---------+-------------+---------------+----------+----------+-------------+
  | UNIT_CONFIG_ID | NAME            | MAX_CPU | MIN_CPU | MEMORY_SIZE | LOG_DISK_SIZE | MAX_IOPS | MIN_IOPS | IOPS_WEIGHT |
  +----------------+-----------------+---------+---------+-------------+---------------+----------+----------+-------------+
  |              1 | sys_unit_config |     2.5 |     2.5 | 17179869184 |   17179869184 |    25000 |    25000 |           2 |
  |           1001 | unit001         |       1 |       1 |  6442450944 |   19327352832 |    10000 |    10000 |           1 |
  |           1002 | unit002         |       1 |       1 |  6442450944 |   19327352832 |    10000 |    10000 |           1 |
  |           1003 | unit003         |       1 |       1 |  6442450944 |   19327352832 |    10000 |    10000 |           1 |
  |           1004 | unit004         |       1 |       1 |  6442450944 |   19327352832 |    10000 |    10000 |           1 |
  |           1005 | unit1           |       6 |       6 | 38654705664 |    2147483648 |     1024 |     1024 |           0 |
  +----------------+-----------------+---------+---------+-------------+---------------+----------+----------+-------------+
  6 rows in set
  

• oceanbase.GV$OB_UNITS

  The GV$OB_UNITS view displays the resource allocation information of all tenants in the cluster.

  Sample statement:

  obclient> SELECT * FROM oceanbase.GV$OB_UNITS\G
  *************************** 1. row ***************************
           SVR_IP: xx.xx.xx.xx
        SVR_PORT: 2882
           UNIT_ID: 1
        TENANT_ID: 1
              ZONE: zone1
           MAX_CPU: 2.5
           MIN_CPU: 2.5
     MEMORY_SIZE: 17179869184
        MAX_IOPS: 25000
        MIN_IOPS: 25000
     IOPS_WEIGHT: 2
     LOG_DISK_SIZE: 17179869184
  LOG_DISK_IN_USE: 191441460
  DATA_DISK_IN_USE: 406847488
           STATUS: NORMAL
     CREATE_TIME: 2022-07-19 11:04:39.226231
  *************************** 2. row ***************************
           SVR_IP: xx.xx.xx.xx
        SVR_PORT: 2882
           UNIT_ID: 1001
        TENANT_ID: 1001
              ZONE: zone1
           MAX_CPU: NULL
           MIN_CPU: NULL
     MEMORY_SIZE: 644245094
        MAX_IOPS: NULL
        MIN_IOPS: NULL
     IOPS_WEIGHT: NULL
     LOG_DISK_SIZE: 1932735283
  LOG_DISK_IN_USE: 155042605
  DATA_DISK_IN_USE: 211812352
           STATUS: NORMAL
     CREATE_TIME: 2022-07-19 13:48:36.308843
  *************************** 3. row ***************************
           SVR_IP: xx.xx.xx.xx
        SVR_PORT: 2882
           UNIT_ID: 1001
        TENANT_ID: 1002
              ZONE: zone1
           MAX_CPU: 1
           MIN_CPU: 1
     MEMORY_SIZE: 5798205850
        MAX_IOPS: 10000
        MIN_IOPS: 10000
     IOPS_WEIGHT: 1
     LOG_DISK_SIZE: 17394617549
  LOG_DISK_IN_USE: 154632504
  DATA_DISK_IN_USE: 121634816
           STATUS: NORMAL
     CREATE_TIME: 2022-07-19 13:48:36.308843
  *************************** 4. row ***************************
           SVR_IP: xx.xx.xx.xx
        SVR_PORT: 2882
           UNIT_ID: 1002
        TENANT_ID: 1005
              ZONE: zone1
           MAX_CPU: NULL
           MIN_CPU: NULL
     MEMORY_SIZE: 644245094
        MAX_IOPS: NULL
        MIN_IOPS: NULL
     IOPS_WEIGHT: NULL
     LOG_DISK_SIZE: 1932735283
  LOG_DISK_IN_USE: 152132563
  DATA_DISK_IN_USE: 211812352
           STATUS: NORMAL
     CREATE_TIME: 2022-07-19 13:51:56.627867
  *************************** 5. row ***************************
           SVR_IP: xx.xx.xx.xx
        SVR_PORT: 2882
           UNIT_ID: 1002
        TENANT_ID: 1006
              ZONE: zone1
           MAX_CPU: 1
           MIN_CPU: 1
     MEMORY_SIZE: 5798205850
        MAX_IOPS: 10000
        MIN_IOPS: 10000
     IOPS_WEIGHT: 1
     LOG_DISK_SIZE: 17394617549
  LOG_DISK_IN_USE: 158023991
  DATA_DISK_IN_USE: 134217728
           STATUS: NORMAL
     CREATE_TIME: 2022-07-19 13:51:56.627867
  5 rows in set
  

• oceanbase.DBA_OB_RESOURCE_POOLS

  The DBA_OB_RESOURCE_POOLS view displays the resource configurations of all resource pools in the current cluster. unit_count indicates the number of resource units in the resource pool.

  Sample statement:

  obclient> SELECT * FROM oceanbase.DBA_OB_RESOURCE_POOLS;
  +------------------+----------+-----------+----------------------------+----------------------------+------------+----------------+-----------+--------------+
  | RESOURCE_POOL_ID | NAME     | TENANT_ID | CREATE_TIME                | MODIFY_TIME                | UNIT_COUNT | UNIT_CONFIG_ID | ZONE_LIST | REPLICA_TYPE |
  +------------------+----------+-----------+----------------------------+----------------------------+------------+----------------+-----------+--------------+
  |                1 | sys_pool |         1 | 2022-07-19 11:05:18.168896 | 2022-07-19 11:05:18.175708 |          1 |              1 | zone1     | FULL         |
  |             1001 | pool001  |      1002 | 2022-07-19 13:47:55.854548 | 2022-07-19 13:48:36.307978 |          1 |           1001 | zone1     | FULL         |
  |             1002 | pool002  |      1006 | 2022-07-19 13:49:53.869792 | 2022-07-19 13:51:56.626742 |          1 |           1001 | zone1     | FULL         |
  +------------------+----------+-----------+----------------------------+----------------------------+------------+----------------+-----------+--------------+
  3 rows in set