# Continue-As-New - PHP SDK

> For the complete documentation index, see [llms.txt](https://docs.temporal.io/llms.txt).
> Any documentation page is available as raw Markdown by appending `.md` to its URL.

> Use Temporal's Continue-As-New in PHP to manage large Event Histories by atomically creating new Workflow Executions with the same Workflow Id and fresh parameters.

This page covers the following for PHP developers:

- [What is Continue-As-New?](#what)
- [Use Continue-As-New](#how)
- [When is it right to Continue-As-New?](#when)
- [Test Continue-As-New](#how-to-test)

## What is Continue-As-New? 

[Continue-As-New](/workflow-execution/continue-as-new) lets a Workflow Execution close successfully and creates a new Workflow Execution.
You can think of it as a checkpoint when your Workflow gets too long or approaches certain scaling limits.

The new Workflow Execution is in the same [chain](/workflow-execution#workflow-execution-chain); it keeps the same Workflow Id but gets a new Run Id and a fresh Event History.
It also receives your Workflow's usual parameters.

## Use Continue-As-New with the PHP SDK 

First, design your Workflow parameters so that you can pass in the "current state" when you Continue-As-New into the next Workflow run.
This state is typically set to `None` for the original caller of the Workflow.

[View the source code](https://github.com/temporalio/samples-php/blob/master/app/src/SafeMessageHandlers/MessageHandlerWorkflowInterface.php) in the context of the rest of the application code.

```php
final class ClusterManagerInput {
    public function __construct(
        public ?ClusterManagerState $state = null,
        public bool $testContinueAsNew = false,
    ) {}
}

#[Workflow\WorkflowInterface]
interface MessageHandlerWorkflowInterface
{
#[Workflow\WorkflowMethod]
public function run(ClusterManagerInput $input);
}

````
The test hook in the above snippet is covered [below](#how-to-test).

Inside your Workflow, call the [`continueAsNew()`](https://php.temporal.io/classes/Temporal-Workflow.html#method_continueAsNew) function with the same type.
This stops the Workflow right away and starts a new one.

[View the source code](https://github.com/temporalio/samples-php/blob/master/app/src/SafeMessageHandlers/MessageHandlerWorkflow.php) in the context of the rest of the application code.

```php
Workflow::continueAsNew(
    Workflow::getInfo()->type->name,
    [new ClusterManagerInput($this->state, $input->testContinueAsNew)],
);
````

### Considerations for Workflows with Message Handlers 

If you use Updates or Signals, don't call Continue-as-New from the handlers.
Instead, wait for your handlers to finish in your main Workflow before you run `continueAsNew`.
See the [`allHandlersFinished`](message-passing#wait-for-message-handlers) example for guidance.

## When is it right to Continue-As-New with the PHP SDK? 

Use Continue-as-New when your Workflow might hit [Event History Limits](/workflow-execution/event#event-history).

Temporal tracks your Workflow's progress against these limits to let you know when you should Continue-as-New.
Call `Workflow::getInfo()->shouldContinueAsNew` to check if it's time.

## Test Continue-As-New with the PHP SDK 

Testing Workflows that naturally Continue-as-New may be time-consuming and resource-intensive.
Instead, add a test hook to check your Workflow's Continue-as-New behavior faster in automated tests.

For example, when `testContinueAsNew == true`, this sample creates a test-only variable called `$this->maxHistoryLength` and sets it to a small value.
A helper method in the Workflow checks it each time it considers using Continue-as-New:

[View the source code](https://github.com/temporalio/samples-php/blob/master/app/src/SafeMessageHandlers/MessageHandlerWorkflow.php) in the context of the rest of the application code.

```php
private function shouldContinueAsNew(): bool
{
    if (Workflow::getInfo()->shouldContinueAsNew) {
        return true;
    }

    // This is just for ease-of-testing.  In production, we trust temporal to tell us when to continue as new.
    if ($this->maxHistoryLength !== null && Workflow::getInfo()->historyLength > $this->maxHistoryLength) {
        return true;
    }

    return false;
}
```