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Limits on Task Resource Usage

Using system generation parameters, you can limit task usage of the following resources:

You can establish limits for online tasks. Since external request units are processed using online task, limits may also be specified for them.

You use the following parameters to define online task limits and control their enforcement.

Establishing Resource Limits

The CALL/DBIO/LOCK/STORAGE LIMIT FOR ONLINE TASKS parameter of the system generation SYSTEM statement defines the limit for each resource.

Overriding Limits

You can override these limits:

Enforcing Defined Limits

The LIMITS FOR ONLINE ARE ENABLED/DISABLED/ OFF parameter of the system generation SYSTEM statement controls the enforcement of defined limits. You can override the system generation specification at runtime by means of the DCMT VARY LIMITS command.

Note: Limits on task resource usage can be enforced only if TASK is specified on the Statistics parameter of the SYSTEM statement. Task statistics are described briefly under Statistics Collection.

Limiting the Number of Application Threads

You can achieve additional control over task resource usage by limiting the number of threads that can be active concurrently for a given task. For tasks that are large consumers of system resources, you should include the MAXIMUM CONCURRENT THREADS parameter in the system generation TASK statement. Alternatively, the MAXIMUM CONCURRENT parameter of the DCMT VARY TASK command can be used at runtime to limit the number of concurrently active task threads.

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