Tags & Labels
What are Tags & Labels?
In Factry Historian, tags and labels are two separate but complementary ways of attaching metadata to your Measurements and Calculations.
- Tags are written into the time-series database together with each data point. They are part of the underlying storage structure (e.g. in InfluxDB).
- Labels are managed within Factry Historian itself. They are used to group, filter, and organize data for data management, or forwarding.
Why does it matter?
Both tags and labels help you make sense of your data at scale. They enable you to:
- Filter or group measurements by metadata (such as product, location, or asset type)
- Route specific subsets of data to external systems using Forwarders
- Keep your system maintainable as your setup grows
Using tags and labels consistently allows you to manage hundreds or thousands of signals without relying on naming conventions alone.
How does it fit in the system?
Tags (TSDB-level)
Tags are part of each data point in the time-series database. In InfluxDB, they are indexed key-value pairs used for fast querying and grouping. They are attached at write time, meaning they must be defined prior to the data being written.
Example: A temperature measurement might be stored with the following tags:
- asset=Line1.Furnace
- unit=Celsius
- phase=heating
You can use these tags to filter data in dashboards or aggregate across a group.
Labels (Historian-level)
Labels are maintained in Factry Historian and apply to measurements and calculations. They are used to:
- Categorize data sets for easy management
- Select subsets of data for forwarding to external systems using the Forwarders feature
Labels can be changed at any time without touching the underlying TSDB.
Example: You might apply these labels to a set of measurements:
- Energy
- Team A
- Forward_to_Corporate
These labels can then be used to filter data while administering Factry Historian, or to selectively forward it.
Example
Let’s say you have energy meters on five different lines.
Each measurement is written with the following tags:
- line=LineX (with X from 1 to 5)
Inside Factry Historian, you assign labels to all five energy measurements:
- Energy
- Forward_to_Corporate
You now have:
- Fast filtering by line using tags
- Centralized control over what gets forwarded to the corporate MQTT broker
When you use it
You use tags:
- During data collection and ingestion
- For filtering and grouping in dashboards and queries
- To optimize time-series queries on indexed fields
You use labels:
- To manage configuration and routing within Factry Historian
- To group signals by purpose, not just origin
- When using the Forwarders feature to send specific sets of data to other systems
Common misconceptions
- Tags and labels are not interchangeable. Tags live in the TSDB and are fixed once written. Labels are managed in the Historian and can be updated at any time.
- Tags must be defined before data arrives. Labels can be applied later.
- Labels do not affect how data is stored in the TSDB, only how it is used and organized within the application.
Best practices
- Use tags for static metadata tied to the source of the data, such as asset or product.
- Use labels for categorization of data (e.g. energy, quality, process).
- Apply labels consistently across similar measurements to make administration and forwarding easier.
More information
- Creating and deleting labelsCreating and deleting labels
- Configuring forwarders using labels