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15.7.2.2 CREATE RESOURCE GROUP Statement

CREATE RESOURCE GROUPgroup_name    TYPE = {SYSTEM|USER}    [VCPU [=]vcpu_spec [,vcpu_spec] ...]    [THREAD_PRIORITY [=]N]    [ENABLE|DISABLE]vcpu_spec: {N |M -N}

CREATE RESOURCE GROUP is used for resource group management (seeSection 7.1.16, “Resource Groups”). This statement creates a new resource group and assigns its initial attribute values. It requires theRESOURCE_GROUP_ADMIN privilege.

group_name identifies which resource group to create. If the group already exists, an error occurs.

TheTYPE attribute is required. It should beSYSTEM for a system resource group,USER for a user resource group. The group type affects permittedTHREAD_PRIORITY values, as described later.

TheVCPU attribute indicates the CPU affinity; that is, the set of virtual CPUs the group can use:

  • IfVCPU is not given, the resource group has no CPU affinity and can use all available CPUs.

  • IfVCPU is given, the attribute value is a list of comma-separated CPU numbers or ranges:

    • Each number must be an integer in the range from 0 to the number of CPUs − 1. For example, on a system with 64 CPUs, the number can range from 0 to 63.

    • A range is given in the formM −N, whereM is less than or equal toN and both numbers are in the CPU range.

    • If a CPU number is an integer outside the permitted range or is not an integer, an error occurs.

ExampleVCPU specifiers (these are all equivalent):

VCPU = 0,1,2,3,9,10VCPU = 0-3,9-10VCPU = 9,10,0-3VCPU = 0,10,1,9,3,2

TheTHREAD_PRIORITY attribute indicates the priority for threads assigned to the group:

  • IfTHREAD_PRIORITY is not given, the default priority is 0.

  • IfTHREAD_PRIORITY is given, the attribute value must be in the range from -20 (highest priority) to 19 (lowest priority). The priority for system resource groups must be in the range from -20 to 0. The priority for user resource groups must be in the range from 0 to 19. Use of different ranges for system and user groups ensures that user threads never have a higher priority than system threads.

ENABLE andDISABLE specify that the resource group is initially enabled or disabled. If neither is specified, the group is enabled by default. A disabled group cannot have threads assigned to it.

Examples:

  • Create an enabled user group that has a single CPU and the lowest priority:

    CREATE RESOURCE GROUP rg1  TYPE = USER  VCPU = 0  THREAD_PRIORITY = 19;

  • Create a disabled system group that has no CPU affinity (can use all CPUs) and the highest priority:

    CREATE RESOURCE GROUP rg2  TYPE = SYSTEM  THREAD_PRIORITY = -20  DISABLE;

Resource group management is local to the server on which it occurs.CREATE RESOURCE GROUP statements are not written to the binary log and are not replicated.