Defining Workload Attributes¶

Introduction¶

A typical database has more than one workload running simultaneously with a different acceptable level of latency and throughput. By defining the attributes of each workload, you can specify how ScyllaDB will handle requests depending on the workload to which they are assigned.

You can define a workload’s attribute using the service level concept. The service level CQL commands allow you to attach attributes to users and roles. When a user logs into the system, all of the attributes attached to that user and to the roles granted to that user are combined and become a set of workload attributes.

See Service Level Management for more information about service levels.

Prerequisites¶

• An authenticated and authorized user

• At least one role created.

Procedure¶

1. Create a service level with the desired attribute.

   CREATE SERVICE LEVEL <service_level_name> WITH <attribute> [ AND <attribute>];
   

   For example:

   CREATE SERVICE LEVEL sl2 WITH timeout = 500ms AND workload_type=interactive;
   

   See Available Attributes.

2. Assign a service level to a role or user:

   ATTACH SERVICE_LEVEL <service_level_name> TO <role_name|user_name>;
   

   For example:

   ATTACH SERVICE LEVEL sl2 TO scylla;
   

You can modify the service level attributes with the ALTER SERVICE LEVEL command:

ALTER SERVICE LEVEL <service_level_name> WITH <attribute> [ AND <attribute>];

For example:

ALTER SERVICE LEVEL sl2 WITH timeout = null;

Available Attributes¶

Specifying Service Level Timeout¶

You can specify the timeout for a service level (in milliseconds or seconds) with the timeout attribute.

For example:

CREATE SERVICE LEVEL primary WITH timeout = 30ms;

Specifying the timeout value is useful when your workloads have different acceptable latency levels.

Specifying Workload Type¶

You can specify the workload type for a service level with the workload_type attribute.

For example:

CREATE SERVICE LEVEL secondary WITH workload_type = 'batch';

Specifying the workload type allows ScyllaDB to handle sessions more efficiently (for example, depending on whether the workload is sensitive to latency).