About Historian tag ownership
- Last UpdatedFeb 27, 2025
- 2 minute read
Although all tags are created and stored with their associated data in a Historian server, each tag has an implicit "owner". That owner is the entity responsible for creation and re-creation of that tag and for sending data associated with it. Tag ownership may change over time, but at any point in time it can be clearly identified. A tag can have one of three possible owners:
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AVEVA Application Server. When an application server is deployed, a tag is created and its name is automatically generated from the object hierarchy. If, for some reason, that Historian tag completely disappeared from the Historian server, the AVEVA Application server could recreate that tag automatically at the next deployment.
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AVEVA Historian SDK application, if it adds a tag before sending data. As in the case with the AVEVA Application Server, that application can re-create the tag automatically if necessary.
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AVEVA Historian, if that tag is an IDAS tag or one created manually through the Configuration Editor or a stored procedure.
AVEVA Historian can become a tag owner for already-collected data if the associated AVEVA Application Server deployment or SDK application no longer exists and is no longer able to re-create or send data.
If a tag must be renamed, the first step is renaming it in the owner and then forcing the owner to re-create a tag with the new name. For AVEVA Application Server, it means making changes in the object hierarchy and redeploying. For an SDK application, it means renaming the tag in the application, restarting the application to reconnect to the Historian, and then reconfiguring the current most recent version of the tag.
If, however, the Application Server no longer exists or the application is no longer used, the tag ownership is already transferred to the Historian and that first step is unnecessary.
After the tag owner re-creates the tag with a new name, the new incoming data will be stored under that new tag name. However, previously collected data is still associated with the old name. To make that old data visible, you can use the Tag Rename Utility to update previous tag metadata records with the new tag name without changing the tagids of those records.