Index span tags to create a Troubleshooting MetricSet

Create custom span tags to improve filtering and troubleshooting capabilities in Tag Spotlight in Splunk RUM.

You must be an admin to do this task.

You can create custom span tags that are meaningful to your team, such as:

  • Process IDs that are unique to your team

  • Customer support tier or loyalty level

  • Department

  • Internal geographic locations for facilities

  • Branch locations

For information to help you decide which span tags to index, see Reference and best practices for span tags and Troubleshooting MetricSets.

Tip: Your Splunk Observability Cloud contract may determine the number of span tags you can index to generate Troubleshooting MetricSets. If you choose not to index any additional span tags, you can still view tags in your spans when analyzing whole traces.
  1. Create a custom span tag:
    Tip:

    Avoid high cardinality in MetricSets

    Choose tags with a reasonable amount of cardinality. Tags like userID, or sessionID have high cardinality because there is a unique value for users in your organization and visitors to your application. Creating a troubleshooting MetricSet for each userID is not optimal for performance. For high-cardinality, ID-based tags, full-fidelity session search is a better option, see Filter your data by tags in Splunk RUM.

    High cardinality MetricSets can also affect your org limits System limits for Splunk RUM. Limits are determined by your subscription: enterprise and standard. For more information on each type of subscription, see Splunk RUM Pricing .

  2. To add attributes to the span, see Splunk RUM’s API Methods.
  3. Index the span tag by adding it to a MetricSet.
    1. Navigate to the MetricSets configuration page through either of these paths:

      • Select Digital Experience and then in the Real user monitoring section select Overview. On the Overview page, select RUM Configuration > RUM MetricSet as seen in the following screenshot.

        Settings panel for adding metric sets.

      • From the left navigation menu, select Settings > APM & RUM MetricSets > RUM

        Settings panel for adding metric sets.

    2. Choose the tag you want to index to trigger the cardinality analyzer.
    3. View the results of the cardinality check:

      • If the cardinality check passes, select Add MetricSet and confirm with the check mark.

      • If the cardinality check fails, check to see if you've exceeded your entitlements.

View custom tags in Tag Spotlight.