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Task flow

Last Updated: May 11, 2020

Definition

  • A task flow is a group of one or more tasks which are organized as a directed acyclic graph (DAG).
    • The task flow is the basis of data analysis. The following section describes how to create a task flow.

Create a task flow

  • On the Data Analysis tab, double-click Add Task Flow on the left of the tab, or click the Add Task Flow button in the middle of the tab.
    Add a task flow

View and edit a task flow

  • To view a task flow, double-click the target task flow in the left-side directory tree, or right-click the target task flow and click DAG.
    View a task flow

  • On the preceding tab, you can click the target task, or click Schedule, Staffing, or Operation Records to view and configure parameters as required.

Dependencies between tasks in a task flow

Create a dependency

  • Move the pointer over a task in the DAG and drag a line, as shown in the following figure. You can drag the line to connect the task to another one. In this way, you create a dependency.Create a dependency

Dependency direction

Tasks in a task flow are run in the order as indicated by the dependency direction. Take the following task flow as an example.DependencyIn the preceding task flow, tasks are run in the following order:

  1. a
  2. b
  3. c and e (concurrently)

Schedule

  • Enable: indicates whether to enable the recurring schedule. You can turn on this switch to enable the recurring schedule.
  • Valid Period: the validity period for the schedule. The default value is 1970-01-01~9999-01-01, indicating that the schedule is always enabled.
  • Schedule Cycle: the frequency for the schedule. Valid values are Days, Weeks, and Months.
  • Schedule Time: the specific time when the schedule is executed.
  • Cron Expression: a string that represents the schedule cycle and time.

After you complete the preceding configuration, click OK. Then, DMS Enterprise schedules tasks based on the configuration.

Staffing

  • Owner: Only the owner of a task flow has the permissions to edit the task flow and task configurations. The owner can also perform a dry run on tasks and receive task running alerts.
  • Stakeholder: A stakeholder of a task flow has the permissions to view the task flow and task configurations and perform a dry run on tasks. However, a stakeholder does not have the permissions to edit the task flow and task configurations.
  • Administrator and DBA: In addition to the permissions of a stakeholder, the administrator and DBA have the permissions to edit and reassign the owner of a task flow.

Operation Records

In the Operation Records dialog box, you can find all modifications to the task flow.