Architecture of the administrative task scheduler

The administrative task scheduler is a started task that can be seen as an additional Db2 address space, even if it is in a separate process. The administrative task scheduler is accessed through an SQL API and stores the scheduled tasks in two redundant task lists.

The administrative task scheduler is part of Db2 for z/OS. When properly configured, it is available and operable with the first Db2 start. The administrative task scheduler starts as a task on the z/OS® system during Db2 startup. The administrative task scheduler has its own address space, named after the started task name.

Each Db2 subsystem has its own distinct administrative task scheduler connected to it. Db2 is aware of the administrative task scheduler whose name is defined in the subsystem parameter ADMTPROC. The administrative task scheduler is aware of Db2 by the subsystem name that is defined in the DB2SSID parameter of the started task.

The administrative task scheduler has an SQL interface consisting of stored procedures (ADMIN_TASK_ADD and ADMIN_TASK_REMOVE) and user-defined table functions (ADMIN_TASK_LIST and ADMIN_TASK_STATUS) defined in Db2. This SQL interface allows you to remotely add or remove administrative tasks, and to list those tasks and their execution status.

The administrative task scheduler executes the tasks according to their defined schedules. The status of the last execution is stored in the task lists as well, and you can access it through the SQL interface.

The following figure shows the architecture of the administrative task scheduler.

Figure 1. Architecture of the administrative task scheduler
Begin figure description. This figure shows the lifecycle of the administrative task scheduler and how it uses task lists. End figure description.