CREATE RESOURCE POOL
Function
CREATE RESOURCE POOL creates a resource pool and specifies the Cgroup of the resource pool.
Precautions
Only a user with the CREATE permission on the current database can perform this operation.
Syntax
CREATE RESOURCE POOL pool_name
[WITH ({MEM_PERCENT=pct | CONTROL_GROUP="group_name" | ACTIVE_STATEMENTS=stmt | MAX_DOP = dop | MEMORY_LIMIT='memory_size' | io_limits=io_limits | io_priority='io_priority' | nodegroup="nodegroupname" | is_foreign=boolean }[, ... ])];
Parameter Description
pool_name
Specifies the name of a resource pool.
The name of a resource pool cannot be same as that of an existing resource pool.
Value range: a string. It must comply with the identifier naming convention.
group_name
Specifies the name of a Cgroup.
NOTE:- You can use either double quotation marks ("") or single quotation marks ('') in the syntax when setting the name of a Cgroup.
- The value of group_name is case-sensitive.
- If group_name is not specified, the string “Medium” will be used by default in the syntax, indicating the Medium Timeshare Cgroup under DefaultClass.
- If a database administrator specifies a Workload Cgroup under Class, for example, control_group set to class1:workload1, the resource pool will be associated with the workload1 Cgroup under class1. The level of the Workload Cgroup can also be specified. For example, control_group is set to class1:workload1:1.
- If a database user specifies the Timeshare Cgroup string (Rush, High, Medium, or Low) in the syntax, for example, control_group is set to High, the resource pool will be associated with the High Timeshare Cgroup under DefaultClass.
Value range: a string. It must comply with the rule in the description, which specifies the created Cgroup.
stmt
Specifies the maximum number of statements that can be concurrently executed in a resource pool.
Value range: numeric data ranging from –1 to 2147483647
dop
Specifies the maximum statement concurrency degree for a resource pool, equivalent to the number of threads that can be created for executing a statement.
Value range: numeric data ranging from 1 to 64
memory_size
Specifies the maximum memory size of a resource pool.
Value range: a string from 1 KB to 2047 GB
mem_percent
Specifies the proportion of available resource pool memory to the total memory or group user memory.
In multi-tenant scenarios, the value of mem_percent of group users or service users ranges from 1 to 100. The default value is 20.
In common scenarios, the value of mem_percent of common users ranges from 0 to 100. The default value is 0.
NOTE:
When both mem_percent and memory_limit are specified, only mem_percent takes effect.io_limits
Specifies the upper limit of IOPS in a resource pool.
The IOPS is counted by ones for column storage and by 10 thousands for row storage.
io_priority
Specifies the I/O priority for jobs that consume many I/O resources. It takes effect when the I/O usage reaches 90%.
There are three priorities: Low, Medium, and High. If you do not want to control I/O resources, use the default value None.
NOTE:
The settings of io_limits and io_priority are valid only for complex jobs, such as batch import (using INSERT INTO SELECT, COPY FROM, or CREATE TABLE AS), complex queries involving over 500 MB data on each DN, and VACUUM FULL.nodegroup
Specifies the name of a logical cluster. The logical cluster must already exist.
If the logical cluster name contains uppercase letters or special characters or begins with a digit, enclose the name with double quotation marks ("") in SQL statements.
is_foreign
In logical cluster mode, specifies the current resource pool to control the resources of common users who are not associated with the logical cluster specified by nodegroup.
NOTE:- nodegroup must specify an existing logical cluster, and cannot be elastic_group or the default node group (group_version1), which is generated during cluster installation.
- If is_foreign is set to true, the resource pool cannot be associated with users. That is, CREATE USER … RESOURCE POOL cannot be used to configure resource pools for users. The resource pool automatically checks whether the users are associated with its logical cluster. If they are not, they will be controlled by the resource pool when performing operations on database nodes in the logical cluster.
Examples
This example assumes that Cgroups have been created by users in advance. For details about how to create Cgroups, see Setting a Cgroup.
-- Create a default resource pool, and associate it with the Medium Timeshare Cgroup under Workload under DefaultClass.
openGauss=# CREATE RESOURCE POOL pool1;
-- Create a resource pool, and associate it with the High Timeshare Workload Cgroup under DefaultClass.
openGauss=# CREATE RESOURCE POOL pool2 WITH (CONTROL_GROUP="High");
-- Create a resource pool, and associate it with the Low Timeshare Workload Cgroup under class1.
openGauss=# CREATE RESOURCE POOL pool3 WITH (CONTROL_GROUP="class1:Low");
-- Create a resource pool, and associate it with the wg1 Workload Cgroup under class1.
openGauss=# CREATE RESOURCE POOL pool4 WITH (CONTROL_GROUP="class1:wg1");
-- Create a resource pool, and associate it with the wg2 Workload Cgroup under class1.
openGauss=# CREATE RESOURCE POOL pool5 WITH (CONTROL_GROUP="class1:wg2:3");
-- Delete the resource pool.
openGauss=# DROP RESOURCE POOL pool1;
openGauss=# DROP RESOURCE POOL pool2;
openGauss=# DROP RESOURCE POOL pool3;
openGauss=# DROP RESOURCE POOL pool4;
openGauss=# DROP RESOURCE POOL pool5;