CREATE RESOURCE GROUP

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CREATE RESOURCE GROUP

Warning: Resource groups are an experimental feature and are not intended for use in a production environment. Experimental features are subject to change without notice in future releases.

Defines a new resource group.

Synopsis

CREATE RESOURCE GROUP name WITH (group_attribute=value [, ... ])

where group_attribute is:

CPU_RATE_LIMIT=integer
MEMORY_LIMIT=integer
[ CONCURRENCY=integer ]
[ MEMORY_SHARED_QUOTA=integer ]
[ MEMORY_SPILL_RATIO=integer ]

Description

Creates a new resource group for Greenplum Database resource management. A resource group is assigned to one or more roles and identifies concurrent transaction, memory, and CPU limits for the role when resource groups are enabled. Only a superuser can create a resource group.

Greenplum Database pre-defines two default resource groups: admin_group and default_group. These group names are reserved.

The max_resource_groups server configuration parameter governs the maximum number of resource groups you can create.

To set appropriate limits for resource groups, the Greenplum Database administrator must be familiar with the queries typically executed on the system, as well as the users/roles executing those queries.

After defining a resource group, assign the group to one or more roles using the ALTER ROLE or CREATE ROLE commands.

Parameters

name
The name of the resource group.
CONCURRENCY integer
The maximum number of concurrent transactions, including active and idle transactions, that are permitted for this resource group. The CONCURRENCY value must be an integer in the range [1 .. max_connections]. The default CONCURRENCY value is 20.
CPU_RATE_LIMIT integer
Required. The percentage of CPU resources to allocate to this resource group. The minimum CPU percentage you can specify for a resource group is 1. The maximum is 100. The sum of the CPU_RATE_LIMIT values specified for all resource groups defined in the Greenplum Database cluster must be less than or equal to 100.
MEMORY_LIMIT integer
Required. The total percentage of Greenplum Database memory resources to allocate to this resource group. The minimum memory percentage you can specify for a resource group is 1. The maximum is 100. The sum of the MEMORY_LIMIT values specified for all resource groups defined in the Greenplum Database cluster must be less than or equal to 100.
MEMORY_SHARED_QUOTA integer
The quota of shared memory in the resource group. Resource groups with a MEMORY_SHARED_QUOTA threshold set aside a percentage of memory allotted to the resource group to share across transactions. This shared memory is allocated on a first-come, first-served basis as available. A transaction may use none, some, or all of this memory. The minimum memory shared quota percentage you can specify for a resource group is 0. The maximum is 100. The default MEMORY_SHARED_QUOTA value is 20. The sum of the MEMORY_SHARED_QUOTA and MEMORY_SPILL_RATIO values specified for a resource group cannot exceed 100.
MEMORY_SPILL_RATIO integer
The memory usage threshold for memory-intensive operators in a transaction. When the transaction reaches this threshold, it spills to disk. The minimum memory spill ratio percentage you can specify for a resource group is 1. The maximum is 100. The upper limit is (100 - MEMORY_SHARED_QUOTA). The default MEMORY_SPILL_RATIO value is 20. The sum of the MEMORY_SHARED_QUOTA and MEMORY_SPILL_RATIO values specified for a resource group cannot exceed 100.

Notes

You cannot submit a CREATE RESOURCE GROUP command in an explicit transaction or sub-transaction.

Use the gp_toolkit.gp_resgroup_config system view to display the limit settings of all resource groups:

SELECT * FROM gp_toolkit.gp_resgroup_config;

Examples

Create a resource group with CPU and memory limit percentages of 35:

CREATE RESOURCE GROUP rgroup1 WITH (CPU_RATE_LIMIT=35, MEMORY_LIMIT=35);

Create a resource group with a concurrent transaction limit of 30, a memory limit of 15, and a CPU limit of 25:

CREATE RESOURCE GROUP rgroup2 WITH (CONCURRENCY=20, 
  MEMORY_LIMIT=15, CPU_RATE_LIMIT=25);

Compatibility

CREATE RESOURCE GROUP is a Greenplum Database extension. There is no provision for resource groups or resource management in the SQL standard.