The SQL Server Resource Governor

The SQL Server Resource Governor is available in the Enterprise and Developer editions of SQL Server. It is not available in the Standard, Web, or Express editions. The Enterprise edition of SQL Server provides the full set of Resource Governor features, including the ability to manage CPU, memory, and I/O resources, and the ability to configure resource pools, workload groups, and resource allocation policies. The Developer edition of SQL Server provides the same Resource Governor features as the Enterprise edition, but it is intended for non-production environments such as development, testing, and training. If you require Resource Governor functionality and have a version of SQL Server that does not support it, you may want to consider upgrading to the Enterprise edition or moving to a cloud-based solution that provides this feature.

The SQL Server Resource Governor has evolved over time, with new features and capabilities added in different versions of SQL Server. Here are some of the key differences in Resource Governor across different versions: SQL Server 2008: The Resource Governor was first introduced in SQL Server 2008 Enterprise edition. It provided the ability to limit CPU usage by defining resource pools and workload groups, and setting maximum CPU usage for each group. However, it did not support memory or I/O resource management. SQL Server 2012: In SQL Server 2012, the Resource Governor added support for memory resource management. This allowed you to control memory usage for different workloads and applications by setting maximum memory limits for each resource pool and workload group. SQL Server 2014: The Resource Governor in SQL Server 2014 introduced the ability to manage I/O resources. This allowed you to limit the amount of I/O that different workloads and applications could consume, helping to prevent I/O contention and improve overall server performance. SQL Server 2016: In SQL Server 2016, the Resource Governor introduced the ability to control the amount of physical I/Os per database file. This allowed you to prevent a single database from consuming too many physical I/Os and impacting the performance of other databases on the server. SQL Server 2017: The Resource Governor in SQL Server 2017 added support for the Intelligent Query Processing feature, which uses machine learning to improve query performance. This allowed you to apply Resource Governor policies to Intelligent Query Processing features, such as batch mode memory grant feedback and adaptive query processing. SQL Server 2019: The Resource Governor in SQL Server 2019 added support for Kubernetes containerization, which allows you to manage and allocate resources for SQL Server workloads running in containers.

To enable the SQL Server Resource Governor using T-SQL, you can use the following steps:

Enable the Resource Governor by running the following command:

ALTER RESOURCE GOVERNOR RECONFIGURE;

This command will enable the Resource Governor feature on your SQL Server instance.

Create a resource pool by running the following command:

CREATE RESOURCE POOL [PoolName] WITH
(
    [MAX_CPU_PERCENT] = 30, -- Maximum CPU usage percentage allowed for the pool
    [MAX_MEMORY_PERCENT] = 50 -- Maximum memory usage percentage allowed for the pool
);

This command will create a resource pool named "PoolName" with a maximum CPU usage of 30% and a maximum memory usage of 50%.

Create a workload group by running the following command:

CREATE WORKLOAD GROUP [GroupName] USING [PoolName];

This command will create a workload group named "GroupName" that uses the "PoolName" resource pool.

Assign a login or user to the workload group by running the following command:

ALTER LOGIN [LoginName] WITH
(
    WORKLOAD_GROUP = [GroupName]
);

This command will assign the login or user "LoginName" to the "GroupName" workload group.

Finally, create a Resource Governor classifier function to map incoming requests to the appropriate workload group based on the criteria you define. For example, you could create a classifier function that assigns requests to a workload group based on the user name, the application name, or other factors.

CREATE FUNCTION [ClassifierFunctionName]()
RETURNS SYSNAME
WITH SCHEMABINDING
ASBEGINDECLARE @workload_group_name AS SYSNAME;
    SET @workload_group_name = (
        SELECT [GroupName]
        FROM [dbo].[MyClassifierTable]
        WHERE [Criteria] = SUSER_SNAME()
    );
    RETURN @workload_group_name;
END;

This command will create a classifier function named "ClassifierFunctionName" that assigns requests to the appropriate workload group based on the criteria you define in the [dbo].[MyClassifierTable] table.

Once you have completed these steps, the Resource Governor will be enabled and configured on your SQL Server instance, and requests will be automatically routed to the appropriate workload group based on the criteria you have defined.

Here are some additional queries that you can use to manage the SQL Server Resource Governor using T-SQL:

To view the current configuration of the Resource Governor, including resource pools and workload groups, you can run the following command:

SELECT * FROM sys.resource_governor_configuration;

This command will display a list of all the resource pools and workload groups configured on your SQL Server instance, along with their associated settings.

To modify the settings of an existing resource pool or workload group, you can use the ALTER RESOURCE POOL or ALTER WORKLOAD GROUP command, respectively. For example, to change the maximum CPU usage for a resource pool named "PoolName" to 40%, you could run the following command:

ALTER RESOURCE POOL [PoolName] WITH MAX_CPU_PERCENT = 40;

This command will modify the "PoolName" resource pool to allow a maximum CPU usage of 40%.

To remove a resource pool or workload group from the Resource Governor, you can use the DROP RESOURCE POOL or DROP WORKLOAD GROUP command, respectively. For example, to remove a workload group named "GroupName", you could run the following command:

DROP WORKLOAD GROUP [GroupName];

This command will remove the "GroupName" workload group from the Resource Governor.

To view the current status of the Resource Governor, including CPU usage and memory usage for each resource pool and workload group, you can run the following command:

SELECT * FROM sys.dm_resource_governor_resource_pools;
SELECT * FROM sys.dm_resource_governor_workload_groups;

These commands will display information about the current resource usage for each resource pool and workload group, allowing you to monitor and optimize your SQL Server resource allocation.

By using these and other T-SQL commands, you can effectively manage the SQL Server Resource Governor and optimize the performance of your SQL Server instances.

To view the current workload group assignments for a given user or login, you can run the following command:

SELECT SUSER_SNAME(), request_id, group_id
FROM sys.dm_exec_sessions
WHERE group_id IS NOT NULL;

This command will display the current workload group assignments for the currently logged-in user, along with the request ID for each session.

To view the current active requests and their associated workload groups, you can run the following command:

SELECT session_id, request_id, group_id
FROM sys.dm_exec_requests
WHERE group_id IS NOT NULL;

This command will display a list of all currently active requests on the SQL Server instance, along with their associated workload groups.

To view the current resource usage by each session or request, you can run the following command:

SELECT session_id, request_id, scheduler_id, current_tasks_count, active_requests_count, pending_io_count
FROM sys.dm_exec_sessions
WHERE is_user_process = 1;

This command will display a list of all currently active user sessions on the SQL Server instance, along with their current resource usage statistics.

To manually force a request to run in a specific workload group, you can use the SET WORKLOAD GROUP command. For example, to force a request with a specific session ID to run in a workload group named "GroupName", you could run the following command:

SET WORKLOAD GROUP [GroupName] FOR SESSION <session_id>;

This command will force the specified session to run in the "GroupName" workload group.

By using these and other T-SQL commands, you can effectively manage the SQL Server Resource Governor and optimize the performance of your SQL Server instances.