For Each flow logic

  • Release version: Yokohama
  • Updated January 30, 2025
  • 2 minutes to read
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    Summary of For Each flow logic

    The For Each flow logic in ServiceNow allows you to apply one or more actions to each record within a list sequentially. It processes each item individually, enabling granular handling of records in workflows. This flow logic is particularly useful for scenarios like sending notifications or updating multiple records based on a list generated dynamically.

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    Important: Data pill values set inside a For Each branch are only accessible within that branch and cannot be referenced outside it. Processing large lists can be resource-intensive, so performance optimization may be necessary.

    Inputs and Outputs

    • Inputs: Accepts a list of records or Sys ID values, typically produced by actions like Look Up Records. You can sort these records beforehand if processing order matters.
    • Outputs: Provides the current record in the loop as a data pill, which can be used by subsequent actions within the loop branch.

    Performance Considerations

    • Avoid processing lists larger than 1000 records in a single For Each loop to maintain optimal flow performance.
    • For larger datasets, split the list into smaller batches and use multiple flows.
    • Disable reporting via the com.snc.processflow.reporting.level system property to reduce overhead when iterating over many records.

    General Guidelines

    • Do not place stages inside a For Each block; stages can only be added before or after the block.
    • Avoid nesting For Each loops that process many records to prevent exceeding flow transaction quotas (flows running longer than one hour).

    Example Use Case

    An example flow triggers when a change request is created. It uses a Look Up Records action to find Configuration Items related to the requester and then applies a For Each loop to send emails about each potentially affected Configuration Item. The flow execution details track each configuration item processed in the loop.

    Additional Resources

    For comprehensive flow design, consider related flow logic such as Assign subflow outputs, Call a workflow, Do the following until, If flow logic, and more to build complex and efficient workflows.

    Apply one or more actions to each record in a list of records.

    The For Each flow logic applies one or more actions to a list of records. The flow applies the actions contained within the flow logic to each record in the list.
    Note:
    When you set a data pill value from inside a For each item branch of flow logic, the data pill value is only available to other actions in the same branch. Referencing a data pill value that was set inside a For each branch from outside of the flow logic branch produces a null value.

    Iterating over a large number of records can be resource intensive, especially when the For Each logic block includes complex actions for each iteration. To avoid performance issues, turn off reporting using the com.snc.process_flow.reporting.level system property. For more information, see Workflow Studio flow system properties.

    Inputs

    Items
    Data type: Records
    List of Sys ID values or Records data pill specifying the records to process in sequence. You can use a Look Up Records action to generate a list of records. For more information, see Look Up Records action.
    Note:
    If you want to process items in a particular order, you must first sort the items in this input in advance. For example, use the Order by option to sort the results of a Look Up Records action.

    Outputs

    [Table name] Record
    Data type: Record
    Current record in the loop.
    Note:
    By default, all flow loops only store execution details for the first and last iterations of a loop. To report on all iterations of a loop, create a flow execution setting record for each flow that you want to collect loop execution details. For more information about flow execution settings, see Flow execution settings.

    Send an email for each configuration item potentially affected by a change

    Configuration of the For Each flow logic using a list of Configuration Item records

    This example flow starts when a change request record is created. The flow uses a Look Up Records action to find Configuration Item records assigned to the requester of the change request. The flow uses For Each flow logic to send an email about each configuration that might be affected by the change request. The output of the Look Up Records action contains the list of records to process.

    Flow execution details of the For Each flow logic

    The flow execution details show the configuration item record used for each iteration of the loop.

    General guidelines

    Use these general guidelines with a For Each flow logic.

    Avoid adding more than 1000 items
    Avoid iterating over lists with more than 1000 records. Keep your list of records smaller to optimize flow performance. To iterate over lists with more than 1000 records, divide the list into smaller sections and use multiple flows.
    Avoid defining stages that depend on a For Each flow logic
    Flow Designer prevents you from adding stages within a For Each block. You can only add stages before or after a For Each block.
    Avoid nested For Each loops
    Avoid nested For Each loops that process many records. Nested loops may cause the flow to run until it is stopped by the flow transaction quota rule, which prevents flows from running longer than an hour. For more information about transaction quotas, see Transaction quotas.