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TrendMiner uses tag names as identifiers in saved work and analysis since the tag names are the only common denominators between all different time series data sources. As a result tag names need to be unique and duplicate tag names are not supported.

Impact/Behavior

Technically nothing prevents you from syncing the same tag name via different data sources but the behavior in TrendMiner is undefined. When searching for the tag you might see multiple search results but adding the tag to the chart might fail as underlying a different tag with the same name might be linked. Loading saved work might start failing (e.g. "Oops, something went wrong" or other loading errors), searches and monitors might start behaving unpredictable, ...

For this reason TrendMiner support will not investigate issues which might be caused by duplicate tags and will ask to remove duplicate tags before proceeding investigation.

How to prevent duplicate tags?

To avoid/prevent duplicate tags we always recommend to configure a prefix when adding a data source. Note that it is not possible to configure a prefix after a data source is added or to edit a prefix of an existing prefix as this would also update the tag name and therefore break existing saved work based on tags from this data source.

Only in exceptional cases and when admins can guarantee no duplicate tag names will be synced from different data sources it is allowed to add data sources without prefixes.

How to solve?

In case you accidentally end up with duplicate tag names the only solution is to delete one of the data sources which includes the duplicate tags and add it again with a prefix. Saved work based on tags from the deleted data sources will break and users will need to be edit/update their work to include the new prefixed tags.

Renaming/reusing tags

If a tag is renamed in the data source TrendMiner will consider the old tag deleted and will create a new tag with the new name. No link between the old and the new tag name will exist in TrendMiner. As a result saved work based on the old tag name will break and the new tag will need to re-index (the old historical data will not be linked to the new tag).

If a tag gets deleted in the data source and the name is reused for a different tag TrendMiner will consider this to be the same (old) tag (the old tag will be undeleted). As a result, the historical data of the old tag will become available again in searches, monitors and other analysis and data from the new tag will just be appended to the old tag's data. Re-indexing the tag would clear the full history but the saved work (views, dashboards, searches, ...) based on this tag will load the new tag.