How to fix ER_RESOURCE_GROUP_EXISTS (3650): Resource group already exists in MySQL

Query the INFORMATION_SCHEMA to see all existing resource groups:

SELECT * FROM INFORMATION_SCHEMA.RESOURCE_GROUPS;

Or check for a specific resource group:

SELECT * FROM INFORMATION_SCHEMA.RESOURCE_GROUPS 
WHERE RESOURCE_GROUP_NAME = 'your_group_name';

This will help you verify whether the resource group already exists and view its current configuration.

If you need to replace the existing resource group with new settings, drop it first:

DROP RESOURCE GROUP your_group_name;

Note: You cannot drop the default system resource groups (USR_default and SYS_default). You also need the RESOURCE_GROUP_ADMIN privilege to drop resource groups.

After dropping, you can recreate it:

CREATE RESOURCE GROUP your_group_name
  TYPE = USER
  VCPU = 0-3
  THREAD_PRIORITY = 5;

If you want to change the configuration of an existing resource group instead of recreating it, use ALTER RESOURCE GROUP:

ALTER RESOURCE GROUP your_group_name
  VCPU = 0-7
  THREAD_PRIORITY = 10;

This approach is safer than dropping and recreating, as it preserves the resource group and updates its properties without disrupting threads currently assigned to it.

If the existing resource group should remain unchanged, simply choose a different name:

CREATE RESOURCE GROUP new_group_name
  TYPE = USER
  VCPU = 4-7
  THREAD_PRIORITY = 8;

Resource group names must be unique within the MySQL instance, so using a descriptive, unique name prevents conflicts.

For migration or initialization scripts, add checks to prevent duplicate creation attempts. While MySQL does not support CREATE RESOURCE GROUP IF NOT EXISTS syntax, you can check existence programmatically:

-- Check if resource group exists
SET @group_exists = (SELECT COUNT(*) FROM INFORMATION_SCHEMA.RESOURCE_GROUPS 
                     WHERE RESOURCE_GROUP_NAME = 'your_group_name');

-- Conditional creation would need to be handled in application code

In application code (e.g., Node.js):

const [groups] = await connection.query(
  "SELECT * FROM INFORMATION_SCHEMA.RESOURCE_GROUPS WHERE RESOURCE_GROUP_NAME = ?",
  ['your_group_name']
);

if (groups.length === 0) {
  await connection.query(
    "CREATE RESOURCE GROUP your_group_name TYPE = USER VCPU = 0-3"
  );
}