Correlation
Summarize
Summary of Correlation
Correlation establishes a synchronization relationship between records on different instances, allowing data from a remote record to update a local record. This process is essential for maintaining consistency across systems, with two types of correlation available: Classic correlation fields and Integration Hub Correlation records.
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Key Features
- Classic Correlation Field: Limited to specific record types (Configuration Item, Service, Task) with a Correlation ID field, creating a one-to-one relationship.
- Integration Hub Correlation Records: Utilizes dedicated correlation records, allowing for enhanced management and flexibility.
- Correlation Record Fields: Includes Local Correlation ID, Remote Correlation ID, Local Table, Local Record, Remote System, and State to manage synchronization effectively.
- State Management: Active correlations receive updates, while inactive ones can be queried and reactivated.
Key Outcomes
With correlation capabilities, ServiceNow customers can:
- Synchronize records efficiently between local and remote systems.
- Manage multiple remote correlations for a single local record.
- Track and audit synchronization states without risking data integrity.
- Utilize distinct Correlation IDs to prevent disruptions due to changes in records.
Note: Direct edits to correlation records may disrupt synchronization and lead to data loss; management should be handled through Integration Hub Remote Process Sync.
Establish a synchronization relationship between records that reside on separate instances.
A correlation identifies record data from a remote instance you want to use on a local instance. An integration can use data from a correlated remote record to update a local record. Typically, integrations correlate records to synchronize them and ensure that record changes propagate across instances.
- Classic correlation field
- Integration Hub Correlation records
Classic correlation field
Prior to Integration Hub Remote Process Sync, you could only create correlations with a limited set of record types that had a Correlation ID field. By default, the Correlation ID field is only available to Configuration Item, Service, and Task records. The Correlation ID field stores the globally unique ID of a matching remote record. The Correlation ID identifies the remote record whose data values should be used to update the local record. For example, suppose incident record INC100001 correlates to problem record PRB123456 on a remote instance. Whenever changes are made to fields in remote problem PRB123456, the system uses the Correlation ID to identify that local incident INC100001 receives the same field updates.
A classic correlation creates a one-to-one relationship between a record on the local system and a record on a remote system. One local record can only ever correlate to one remote record. The correlation provides no information about the remote system nor the current state of the correlation. Administrators manually manage classic correlations from the records being updated.
Integration Hub Correlation records
Integration Hub Remote Process Sync extends the functionality of classic correlation with the introduction of dedicated Correlation [ih_sync_correlation] records.
- Local Correlation ID
- The globally unique ID that identifies the correlation on the local system. By default, Integration Hub Remote Process Sync generates a unique sys_id value for this field. The distinct sys_id acts as an alias which prevents the correlation from breaking due to changes in the local record. When Integration Hub Remote Process Sync sends this ID value to a remote system, the receiving instance uses it as the Remote Correlation ID.
- Remote Correlation ID
- The globally unique ID that identifies the correlation on the remote system. By default, Integration Hub Remote Process Sync generates a unique sys_id value for this field. The distinct sys_id acts as an alias which prevents the correlation from breaking due to changes in the remote record. When Integration Hub Remote Process Sync sends this ID value to a remote system, the receiving instance uses it as the Local Correlation ID.
- Local Table
- The table where the correlation creates or updates records. An Integration Hub Remote Process Sync capture definition monitors this table for record changes. Integration Hub Remote Process Sync uses this field to find correlations by table name.
- Local Record
- The record created or updated by a correlation. This field stores the same value as the Correlation ID field from a classic correlation. When other business logic makes changes to this record, the changes do not overwrite the correlation.
- Remote System
- The remote instance where Integration Hub Remote Process Sync sends and receives record changes. Each correlation record can only refer to one remote instance. To correlate the same local record to multiple remote systems simultaneously, you can create multiple correlation records.
- State
- The synchronization state of the correlation. Active correlations receive additions and updates. Inactive correlations do not produce additions or updates, but can be queried for auditing purposes and reactivated as needed.
- Allow management of correlations by Remote Process Sync
- Identify the remote system associated with a correlation
- Provide separate Correlation ID values for the local and remote systems
- Allow correlation of a single local record with multiple remote systems
- Allow correlations to be deactivated and reactivated as needed
- Allow Correlation ID values to be distinct from the sys_id of a remote record