--- title: ECC queue for Discovery description: The External Communication Channel \(ECC\) queue is a connection point between your ServiceNow instance and other systems that integrate with it, most commonly a MID Server. locale: en-US canonical_url: https://www.servicenow.com/docs/r/it-operations-management/discovery/r\_DiscoveryStatusECCQueue.html release: brazil product: Discovery classification: discovery topic_type: reference last_updated: "2026-09-10" reading_time_minutes: 3 breadcrumb: [Discovery status, Configuring Discovery, Discovery, ITOM Visibility, IT Operations Management] --- # ECC queue for Discovery The External Communication Channel \(ECC\) queue is a connection point between your ServiceNow instance and other systems that integrate with it, most commonly a MID Server. ## Contents of the ECC queue The ECC queue contains records that are created during all stages of discovery. Each record is a message from the instance to system your are targeting for discovery, classified as **output**, or a message from that system to the instance, classified as **input**. ECC queue records show the connected flow of probe and sensor activity. They include the XML payload sent to or from an instance and the assets you're targeting. ## Automatic deletion of ECC queue records As your IT Asset Discovery runs, the size of the ECC queue can grow to several gigabytes. Most of the “completed tasks” records are unnecessary, but some might be important for issue resolution. For example, if Discovery is not capturing disk drives on a Windows server, check the ECC Queue for data from the Windows - System Information probe. Retain ECC Queue data for at least a month. By default, records in the ECC queue older than 7 days are deleted automatically. You can set the deletion schedule by updating the ECC queue and the table rotation schedule. The table rotation names are: - **ecc\_queue\_event** - **ecc\_queue** ## Accessing the ECC queue You can access the ECC queue from either of these locations: - **Discovery** > **Output and Artifacts** > **ECC Queue** - **ECC** > **Queue** The following image is an example of a record in the ECC queue. This record shows that a ConnectorProbe was instructed to run and has been processed. Note the XML payload it returned as the discovery task collected data. See [The MID Server ECC queue](https://raw.githubusercontent.com/ServiceNow/ServiceNowDocs/brazil/markdown/servicenow-platform/ecc-queue-mid-server.md) for a description of each field. \[Omitted image "ECCQueue.png"\] Alt text: ECC queue record for a processed ConnectorProbe output message, including its XML payload. ## ECC queue states Input and output messages keep processing until the discovery is finished or terminated. You can monitor the ECC queue to see records populate during discovery and see the states of each record change. ECC queue input records are processed by business rules \(BR\), but not all business rules direct these ECC queue inputs to process. As a result, some ECC queue inputs remain in a ready state. The process is as follows: 1. When new probe instructions are available for the MID Server, the system creates an **output** record with the state of ready. 2. The MID Server then starts processing the probe instructions and the state changes to processing before it finally changes to processed. 3. When a result returns to the MID Server and is ready to be sent to the instance, the system creates an **input** record with the state of ready. 4. While the system processes the payload, the state changes to processing before it finally changes to processed. If any errors are encountered, the state changes to error. You can review errors as a starting point for troubleshooting a failed discovery. ## Debug processing of ECC queue records To use a script debugger, process the payload on the same session as the debugger. Review the business rule which processes the particular ECC queue record and the actual code which processes the payload. ## Properties and parameters that affect the ECC queue The following table lists properties that control aspects of the ECC queue.
Property Description
Save ECC queue attachments The normal behavior for Discovery sensors is to delete attachments to ECC queue entries on successful sensor processing. Enabling this property overrides this behavior and preserves attachments. This is typically done for debugging purposes.To enable this property, navigate to **Discovery Definition** > **Properties**.
**Parent Topic:**[Discovery status](https://raw.githubusercontent.com/ServiceNow/ServiceNowDocs/brazil/markdown/it-operations-management/discovery/c_DiscoveryStatus.md) **Related topics** [Manage ECC Queue content for a MID Server](https://raw.githubusercontent.com/ServiceNow/ServiceNowDocs/brazil/markdown/servicenow-platform/ecc-queue-mid-server.md)