ALTER RESOURCE GROUP

ALTER RESOURCE GROUP 语句用于在当前所选数据库中修改资源组。

语法图

AlterResourceGroupStmt:
   "ALTER" "RESOURCE" "GROUP" IfExists ResourceGroupName ResourceGroupOptionList

IfExists ::=
    ('IF' 'EXISTS')?

ResourceGroupName:
   Identifier

ResourceGroupOptionList:
    DirectResourceGroupOption
|   ResourceGroupOptionList DirectResourceGroupOption
|   ResourceGroupOptionList ',' DirectResourceGroupOption

DirectResourceGroupOption:
    "RU_PER_SEC" EqOpt stringLit
|   "BURSTABLE"

TiDB 支持以下 DirectResourceGroupOption, 其中 Request Unit (RU) 是 TiDB 对 CPU、IO 等系统资源统一抽象的单位。

如果设置了 BURSTABLE 属性，TiDB 允许对应的资源组超出配额后使用空余的系统资源。

示例

创建一个名为 rg1 的资源组，并修改它的属性。

mysql> DROP RESOURCE GROUP IF EXISTS rg1;
Query OK, 0 rows affected (0.22 sec)
mysql> CREATE RESOURCE GROUP IF NOT EXISTS rg1
    ->  RU_PER_SEC = 100
    ->  BURSTABLE;
Query OK, 0 rows affected (0.08 sec)
mysql> SELECT * FROM information_schema.resource_groups WHERE NAME ='rg1';
+------+-------------+-----------+
| NAME | RU_PER_SEC  | BURSTABLE |
+------+-------------+-----------+
| rg1  |         100 | YES       |
+------+-------------+-----------+
1 rows in set (1.30 sec)
mysql> ALTER RESOURCE GROUP rg1
    ->  RU_PER_SEC = 200;
Query OK, 0 rows affected (0.08 sec)
mysql> SELECT * FROM information_schema.resource_groups WHERE NAME ='rg1';
+------+-------------+-----------+
| NAME | RU_PER_SEC  | BURSTABLE |
+------+-------------+-----------+
| rg1  |         200 | NO        |
+------+-------------+-----------+
1 rows in set (1.30 sec)

MySQL 兼容性

MySQL 也支持 ALTER RESOURCE GROUP，但是接受的参数和 TiDB 不同，两者并不兼容。

另请参阅

• DROP RESOURCE GROUP
• CREATE RESOURCE GROUP
• RU