Resource Partitions - Teradata Database

Resource Partitions

Resource Partitions divide the Teradata Database users into groups based on some use or priority strategy, such as by subject area or type of work.

Priority Scheduler provides you with a default Resource Partition named Default. You can create up to four more Resource Partitions. The default Resource Partition has a default partition weight of 100 and has four Performance Groups accessible by users. You can define additional Performance Groups in the default Resource Partition.

The following table presents a logical view of Resource Partition 0.

Performance group...	has a weight of...
L (low)	5.
M (medium)	10.
H (high)	20.
R (rush)	40.

Resources are distributed to the Teradata Database system sessions that specify a Performance Group within a Resource Partition. The parameters associated with the Performance Groups and Allocations Groups of a Resource Partition control this resource allocation.

For detailed information, see the following:

“Performance Groups” on page 707

“Allocation Groups” on page 715

Resource Partition Parameters

You can define up to a maximum of four additional Resource Partitions. The following table briefly describes the parameters of a Resource Partition.

Parameter	Description
ID	An integer from 0 through 4 that identifies the Resource Partition. Priority Scheduler provides resource partition 0 as the default partition.
Resource Partition Name	A unique name for the Resource Partition. The name can contain no more than 16 characters.
Weight	An integer value that is converted into a relative weight at execution time. The relative weight determines the proportion of Teradata Database system resources the Resource Partition will receive.
Limit	An optional number from one through 100 that specifies a percentage limit on the total CPU usage. This limit will be applied to sessions assigned to the Performance Groups associated with the Resource Partition.

Determining the Relative Weight of a Resource Partition

Assigned Resource Partition weights are transformed into relative weights, based on the weights of the currently active resource partitions. Dividing the weight of a Resource Partition by the sum of the weights of all active resource partitions gives the percentage of total Teradata Database system resources that will be made available to that Resource Partition. This percentage is neither a guarantee or a limit on the amount of Resource a Partition will receive. This percentage is the proportion of resource the Resource Partition will be offered relative to other partitions.

Suppose three Resource Partitions are active. Their respective weights are shown in the following table.

Resource Partition...	Has a weight of...
1	10.
2	20.
3	30.

To determine the relative weight of each Resource Partition, do the following:

1 Add the individual respective weights of the active Resource Partitions (10 + 20 + 30) for a sum of 60.

2 Divide each respective weight (10, 20, and 30) by the sum of 60.

The relative weight for each partition is as follows:

Partition 1 = 16%

Partition 2 = 33%

Partition 3 = 50%

Note: The relative weight for Resource Partition 1 is 16%, rather than 17%, because Teradata Database truncates fractional values when doing relative weight calculations.

Limiting Resource Partition CPU Usage

Optionally, you can limit a Resource Partition to a specified percentage of CPU resource usage. This CPU limit has no effect on the scheduling strategy defined by other Priority Scheduler parameters, and does not apply to PE-only nodes. The relative weights of Allocation Groups and Resource Partitions are observed.

The normal distribution of resources prevails within the specified amount of CPU usage. Any other CPU resource limits defined by a Teradata Database system CPU limit are observed.

Suggested Resource Partition Setup

The following list shows a simple approach to Resource Partition setup.

1 Leave the default Resource Partition for internal work.

2 Assign user work to other Resource Partitions.

3 Group applications by the importance of the work.

The following table shows a simple example of this approach.

Resource Partition...	Has a weight of...	And is used for...
0	20	internal work and tools
1	60	tactical queries. These are short, highly-tuned queries that facilitate decision-making in a time-sensitive environment.
2	20	everything else.