Tasks are designed in Workflow Manager and represent an executable set of actions, functions or commands - which define the runtime behavior of thw whole ETL process.
Session task - it needed to run a mapping
Assignment task - can establish the value of a Workflow Variable whose value can be used at a later point in the workflow, as testing criteria to determine if (or when) other workflow tasks/pipelines should be run.
Decision task - enables the workflow designer to set criteria by which the workflow will or will not proceed to the next set of tasks, depending on whether the set criteria is true or false. It tests for a condition during the workflow and sets a flag based on the condition
Email task - sends an email from within a workflow. Email addresses, a subject line and the email message text can be defined. When called from within a Session task, the message text can contain variable session-related metadata.
Event wait task - pauses processing of the pipeline until a specified event occurs. Events can be Pre-defined (file watch) or User-defined (created by an Event Raise task elsewhere in the workflow)
Command task - specifies one or more UNIX command or shell script, DOS command or batch file for Windows servers to run during a workflow. Command task status (success or failure) is held in the task-specific variable: $command_task_name.STATUS.
Some of the most often used tasks:
UNIX and DOS commands can also be run pre- or post- session in a Session task.
Examples / useful tips
Session, Email and Command tasks can be reusable.
Reusable tasks are created within the Task Developer