Avoid reaching the history quota

AWS Step Functions has a hard quota of 25,000 entries in the execution event history. When an execution reaches 24,999 events, it waits for the next event to happen.

• If the event number 25,000 is ExecutionSucceeded, the execution finishes successfully.

• If the event number 25,000 isn't ExecutionSucceeded, the ExecutionFailed event is logged and the state machine execution fails because of reaching the history limit

To avoid reaching this quota for long-running executions, you can try one of the following workarounds:

• Use the Map state in Distributed mode. In this mode, the Map state runs each iteration as a child workflow execution, which enables high concurrency of up to 10,000 parallel child workflow executions. Each child workflow execution has its own, separate execution history from that of the parent workflow.

• Start a new state machine execution directly from the Task state of a running execution. To start such nested workflow executions, use Step Functions' StartExecution API action in the parent state machine along with the necessary parameters. For more information about using nested workflows, see Start Workflow Executions from a Task State or Using a Step Functions API action to continue a new execution tutorial.

  Tip

  To deploy an example of a nested workflow to your AWS account, see Module 13 - Nested Express Workflows.

• Implement a pattern that uses an AWS Lambda function that can start a new execution of your state machine to split ongoing work across multiple workflow executions. For more information, see the Using a Lambda function to continue a new execution tutorial.