---
title: Clean alert history and impact status tables
description: Schedule jobs to mark and remove old alert records in the Alert History \[em\_alert\_history\] and Impact Status \[em\_impact\_status\] tables, to prevent the tables from becoming overloaded with data.
locale: en-US
canonical_url: https://www.servicenow.com/docs/r/australia/it-operations-management/event-management/clean-alert-tables.html
release: australia
product: Event Management
classification: event-management
topic_type: task
last_updated: "2026-03-12"
reading_time_minutes: 1
breadcrumb: [Purge impact status and alert history, Rotate event and alert table for cleanup, Manage and monitor alerts, Configure, Event Management, ITOM AIOps, IT Operations Management]
---

# Clean alert history and impact status tables

Schedule jobs to mark and remove old alert records in the Alert History \[em\_alert\_history\] and Impact Status \[em\_impact\_status\] tables, to prevent the tables from becoming overloaded with data.

## Before you begin

Role required: evt\_mgmt\_admin

## About this task

Schedule the following jobs to remove old alert records:

-   **Backfill**: Determines when alerts are to be marked for deletion.
-   **Clean**: Deletes the alerts.

**Note:** The records in the \[em\_alert\_history\] and \[em\_impact\_status\] tables are deleted by default after three months. This is controlled by the properties **evt\_mgmt.impact\_calculation.cleanup\_age\_seconds.em\_alert\_history** and **evt\_mgmt.impact\_calculation.cleanup\_age\_seconds.em\_impact\_status**. The default value is 7,776,000 seconds \(equivalent to 90 days\).

## Procedure

1.  Navigate to **All** > **System Definition** > **Scheduled Jobs**.

    The **Scheduled Jobs** page appears.

2.  To determine how often to mark alerts for deletion on the **Impact Status** table:

    1.  Locate and select the **Event Management - Backfill Impact Status Table** job.

        The **Scheduled Script Execution** page appears.

        \[Omitted image "scheduled-script-execution.png"\] Alt text: Scheduled Script Execution page

    2.  In the **Repeat Interval** field, configure how often you want the job to run.

        To run the job immediately, select **Execute Now**.

    3.  Select **Update**.

3.  To remove old alerts from the **Impact Status** table:

    1.  Locate and select the **Event Management - Clean Impact Status Table** job.

        The **Scheduled Script Execution** page appears.

        \[Omitted image "scheduled-scipt-execution-clean.png"\] Alt text: Scheduled Script Execution page

    2.  In the **Repeat Interval** field, configure how often you want the job to run.

        To run the job immediately, select **Execute Now**.

    3.  Select **Update**.

4.  Repeat steps [2](https://raw.githubusercontent.com/ServiceNow/ServiceNowDocs/australia/markdown/australia/it-operations-management/event-management/clean-alert-tables.md) and [3](https://raw.githubusercontent.com/ServiceNow/ServiceNowDocs/australia/markdown/australia/it-operations-management/event-management/clean-alert-tables.md) to perform the Backfill and Clean jobs on the **Alert History Table**.


**Parent Topic:**[Purge impact status and alert history](https://raw.githubusercontent.com/ServiceNow/ServiceNowDocs/australia/markdown/australia/it-operations-management/event-management/t_EMConfigurePurge.md)