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
ALTERRESOURCEGROUPIfExistsResourceGroupNameResourceGroupOptionList
IfExists
IFEXISTS
ResourceGroupName
Identifier
ResourceGroupOptionList
DirectResourceGroupOptionResourceGroupOptionListDirectResourceGroupOptionResourceGroupOptionList,DirectResourceGroupOption
DirectResourceGroupOption
RU_PER_SECEqOptstringLitPRIORITYEqOptResourceGroupPriorityOptionBURSTABLE
ResourceGroupPriorityOption
LOWMEDIUMHIGH

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。

参数含义举例
RU_PER_SEC每秒 RU 填充的速度RU_PER_SEC = 500 表示此资源组每秒回填 500 个 RU。
PRIORITY任务在 TiKV 上处理的绝对优先级PRIORITY = HIGH 表示优先级高。若未指定则默认为 MEDIUM
BURSTABLE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。

DROP RESOURCE GROUP IF EXISTS rg1;
Query OK, 0 rows affected (0.22 sec)
CREATE RESOURCE GROUP IF NOT EXISTS rg1 RU_PER_SEC = 100 BURSTABLE;
Query OK, 0 rows affected (0.08 sec)
SELECT * FROM information_schema.resource_groups WHERE NAME ='rg1';
+------+------------+----------+-----------+ | NAME | RU_PER_SEC | PRIORITY | BURSTABLE | +------+------------+----------+-----------+ | rg1 | 100 | MEDIUM | YES | +------+------------+----------+-----------+ 1 rows in set (1.30 sec)
ALTER RESOURCE GROUP rg1 RU_PER_SEC = 200 PRIORITY = LOW;
Query OK, 0 rows affected (0.08 sec)
SELECT * FROM information_schema.resource_groups WHERE NAME ='rg1';
+------+------------+----------+-----------+ | NAME | RU_PER_SEC | PRIORITY | BURSTABLE | +------+------------+----------+-----------+ | rg1 | 200 | LOW | 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