CREATE RESOURCE GROUP
You can use the CREATE RESOURCE GROUP statement to create a resource group.
Synopsis
- CreateResourceGroupStmt
- IfNotExists
- ResourceGroupName
- ResourceGroupOptionList
- DirectResourceGroupOption
- ResourceGroupPriorityOption
- ResourceGroupRunawayOptionList
- DirectResourceGroupRunawayOption
- WatchDurationOption
- ResourceGroupRunawayWatchOption
- ResourceGroupRunawayActionOption
CreateResourceGroupStmt ::=
"CREATE" "RESOURCE" "GROUP" IfNotExists ResourceGroupName ResourceGroupOptionList
IfNotExists ::=
('IF' 'NOT' 'EXISTS')?
ResourceGroupName ::=
Identifier
| "DEFAULT"
ResourceGroupOptionList ::=
DirectResourceGroupOption
| ResourceGroupOptionList DirectResourceGroupOption
| ResourceGroupOptionList ',' DirectResourceGroupOption
DirectResourceGroupOption ::=
"RU_PER_SEC" EqOpt stringLit
| "PRIORITY" EqOpt ResourceGroupPriorityOption
| "BURSTABLE"
| "BURSTABLE" EqOpt Boolean
| "QUERY_LIMIT" EqOpt '(' ResourceGroupRunawayOptionList ')'
| "QUERY_LIMIT" EqOpt '(' ')'
| "QUERY_LIMIT" EqOpt "NULL"
ResourceGroupPriorityOption ::=
LOW
| MEDIUM
| HIGH
ResourceGroupRunawayOptionList ::=
DirectResourceGroupRunawayOption
| ResourceGroupRunawayOptionList DirectResourceGroupRunawayOption
| ResourceGroupRunawayOptionList ',' DirectResourceGroupRunawayOption
DirectResourceGroupRunawayOption ::=
"EXEC_ELAPSED" EqOpt stringLit
| "ACTION" EqOpt ResourceGroupRunawayActionOption
| "WATCH" EqOpt ResourceGroupRunawayWatchOption WatchDurationOption
WatchDurationOption ::=
("DURATION" EqOpt stringLit | "DURATION" EqOpt "UNLIMITED")?
ResourceGroupRunawayWatchOption ::=
EXACT
| SIMILAR
| PLAN
ResourceGroupRunawayActionOption ::=
DRYRUN
| COOLDOWN
| KILL
The resource group name parameter (ResourceGroupName) must be globally unique.
TiDB supports the following DirectResourceGroupOption, where Request Unit (RU) is a unified abstraction unit in TiDB for CPU, IO, and other system resources.
| Option | Description | Example |
|---|---|---|
RU_PER_SEC | Rate of RU backfilling per second | RU_PER_SEC = 500 indicates that this resource group is backfilled with 500 RUs per second |
PRIORITY | The absolute priority of tasks to be processed on TiKV | PRIORITY = HIGH indicates that the priority is high. If not specified, the default value is MEDIUM. |
BURSTABLE | If the BURSTABLE attribute is set, TiDB allows the corresponding resource group to use the available system resources when the quota is exceeded. | |
QUERY_LIMIT | When the query execution meets this condition, the query is identified as a runaway query and the corresponding action is executed. | QUERY_LIMIT=(EXEC_ELAPSED='60s', ACTION=KILL, WATCH=EXACT DURATION='10m') indicates that the query is identified as a runaway query when the execution time exceeds 60 seconds. The query is terminated. All SQL statements with the same SQL text will be terminated immediately in the coming 10 minutes. QUERY_LIMIT=() or QUERY_LIMIT=NULL means that runaway control is not enabled. See Runaway Queries. |
Examples
Create two resource groups rg1 and rg2.
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
PRIORITY = HIGH
BURSTABLE;
Query OK, 0 rows affected (0.08 sec)
CREATE RESOURCE GROUP IF NOT EXISTS rg2
RU_PER_SEC = 200 QUERY_LIMIT=(EXEC_ELAPSED='100ms', ACTION=KILL);
Query OK, 0 rows affected (0.08 sec)
SELECT * FROM information_schema.resource_groups WHERE NAME ='rg1' or NAME = 'rg2';
+------+------------+----------+-----------+---------------------------------+
| NAME | RU_PER_SEC | PRIORITY | BURSTABLE | QUERY_LIMIT |
+------+------------+----------+-----------+---------------------------------+
| rg1 | 100 | HIGH | YES | NULL |
| rg2 | 200 | MEDIUM | NO | EXEC_ELAPSED=100ms, ACTION=KILL |
+------+------------+----------+-----------+---------------------------------+
2 rows in set (1.30 sec)
MySQL compatibility
MySQL also supports CREATE RESOURCE GROUP. However, the acceptable parameters are different from that of TiDB so that they are not compatible.