about_Checkpoint-Workflow
SHORT DESCRIPTION
Describes the Checkpoint-Workflow activity, which takes a checkpoint in a workflow.
LONG DESCRIPTION
The Checkpoint-Workflow activity takes a checkpoint, which saves state and data in the workflow. If the workflow is suspended or interrupted, it can be resumed from the most recent checkpoint, rather than having to be restarted.
The Checkpoint-Workflow activity is valid only in a workflow.
SYNTAX
Workflow <Verb-Noun>
{
Checkpoint-Workflow
}
The Checkpoint-Workflow activity does not accept any parameters, including common parameters and workflow common parameters.
You can place the Checkpoint-Activity checkpoint anywhere in a workflow after the CmdletBinding or Param statement. However, when placing checkpoints, consider the performance cost of collecting the data and writing it to disk on the computer that is running the workflow.
Be sure that the time it takes to rerun a section of the workflow if it is interrupted is greater than the time it takes to write the checkpoint state and data to disk.
Consider taking checkpoints after critical steps so the workflow can be resumed rather than restarted. For example, take a checkpoint after commands that are not idempotent.
ABOUT CHECKPOINTS
A checkpoint is a snapshot of the current state of the workflow, including the current values of variables, and any output generated up to that point, and it saves it to disk.
If a workflow is interrupted, intentionally or unintentionally, Windows PowerShell Workflow automatically uses the data in newest checkpoint to recover and resume the workflow.
When you run the workflow as a job, such as by using the AsJob workflow common parameter, the workflow checkpoints are retained until you delete the job, such as by using the Remove-Job cmdlet. Otherwise, workflow checkpoints are deleted when the workflow completes.
OTHER CHECKPOINTING TECHNIQUES
In addition to the Checkpoint-Workflow activity, Windows PowerShell Workflow supports other checkpointing techniques, including the following:
- PSPersist workflow common parameter
- PSPersist activity common parameter
- PSPersistPreference variable (in a workflow)
For more information about adding a checkpoint to a workflow, see "How to Add Checkpoints to a Workflow."
Examples
The following workflow includes a call to the Checkpoint-Workflow activity after completing a long-running function and a script that share data.
Workflow Test-Workflow
{
$a = Invoke-LongRunningFunction
InlineScript { \\Server\Share\Get-DataPacks.ps1 $Using:a}
Checkpoint-Workflow
Invoke-LongRunningFunction
{
...
}
}
