Start Polling and End Polling

Polling nodes are used to trigger the execution of tasks continuously at a given time interval, after completing previous execution.

Polling nodes will wait for the previously running task to finish execution, then waits for the specified interval of time and then starts the next execution.
Note: All the nodes can be used within the Start and End Polling nodes.
The execution of polling nodes is continued until it is stopped manually, irrespective of child tasks whether they are successfully executed or failed. So, this can be considered as a scheduler which can trigger the execution of other child tasks at a given time interval.

Note: While exporting a polling task, it will export related child tasks as well.

Conditions:

• Only task nodes are allowed within the polling nodes. In case if any other nodes are used, the polling will not be executed and the status in the Polling History and Execution Summary screen will be updated as INVALIDATED.
• No iterations are allowed within the polling nodes.
• Polling nodes are not allowed in components.
• Nested polling nodes are not allowed that is tasks which has polling node cannot be selected in Task nodes that is those tasks cannot be used as child tasks.
• RESTART functionality will not be available for polling tasks.

Designing a Task Using Polling Nodes:

1. Use an existing task or create a new task based on the requirement.
   Note: Refer Create A Task for more details on how to create a task and how to open an existing task.
2. In the Task Design: Overview screen, select the Single Run check box based on the requirement.
   
   Note: “Single Run” feature in task level is used to avoid parallel running of same task (if we use same task inside 2 different polling tasks).
   Therefore, it allows the task to run only once at a time. If two polling tasks have the same child task, then both will be executing at the same point of time if Single Run check box is cleared. If the Single Run check box selected, then one child task will execute and the other will abort.
   
3. Drag and drop the Start Polling, Task and End Polling nodes from the Objects -> SubTasks section and connect the nodes.
   
   
4. Click on the Start Polling node and specify the properties:
   
   
   • Name: Name of the node. A default name is displayed in this field, which the user can edit according to the task and the intent of using the node.
   • Description: A short note on the purpose of the node.
   • Delay (in seconds): Minimum delay is 15 sec by default which can be altered by changing the value of Minimum polling delay in the Edit Server Settings page.
     Do the following to change the value of Minimum polling delay:
     • Click on the Settings drop-down.
     • Click on the Server Settings option.
       
       
     • Edit the desired the Minimum polling delay value.
       
       
5. Click on the Task node and specify the properties. For more details, click here.
6. Click on the End Polling node and specify the properties:
   
   
   • Name: Name of the node. A default name is displayed in this field, which the user can edit according to the task and the intent of using the node.
   • Description: A short note on the purpose of the node.
7. Click on the Trial Run icon to run the task.
   
   
   
   Note: The execution of polling nodes is continued until it is stopped manually. Polling task execution can be triggered either from the Task Design or Task Execution -> Run Tasks screen.
   
8. If the polling task execution is triggered from the Task Design screen, it creates the following:
   • An entry in Polling History screen with STATUS as POLLING, which indicates that the execution is in progress.
     
     
   • An entry in Execution Summary screen for the task with details on how many times the child tasks are executed along with successful/failed count.
     
     
   • An entry in Execution History screen for each round of execution, details of all the child tasks within polling nodes that is if the child task within the polling nodes are executed 50 times, the execution history will have 50 entries with the details of each round of execution.
     
     
     
9. If the polling task is triggered from the Task Execution -> Run Tasks screen, in addition to the above-mentioned entries there will be an entry for parent task in the Execution Summary screen and Execution History screen.
10. Once the execution is triggered, it can be stopped by selecting the record from Polling History screen.
11. Click on the following highlighted icon from the table to display the Stop Confirmation dialog.
    
    
    • Click on the Stop after current run button to stop polling after the current execution.
    • Click on the Stop immediately button to stop polling immediately.
    • Click on the Cancel button to close the window without stopping the polling node execution.
12. If the execution is triggered from the Task Design screen, user can also stop the execution by using Stop Run button available in the Task Design screen.
    
    
13. When the user clicks on Stop Run button, the Stop Confirmation dialog is displayed.
    
    
    • Click on the Stop after current run button to stop polling after the current execution.
    • Click on the Stop immediately button to stop polling immediately.
    • Click on the Cancel button to close the window without stopping the polling node execution.
14. Once polling is stopped, the status of polling task in the Polling History screen will be updated as STOPPED.