Filter and troubleshoot with custom tags

Use custom tags to improve filtering and troubleshooting capabilities in Splunk RUM.

Create custom tags to improve filtering and troubleshooting capabilities in Tag Spotlight in Splunk RUM. First, create a custom span tag, then index it by adding a MetricSet to the span tag. Adding a MetricSet to a span tag gives you all of the features associated with indexed span tags.

Key concepts

How span tags, indexed span tags, and MetricSets relate to each other.

Span tags

Use span tags or processes to break down services and inter-service calls along trace characteristics or attributes. To get additional value from a span tag or process, an administrator can run an action known as indexing, which activates additional analysis of the indexed span tag or process. One benefit of indexing is to get aggregated metrics, called MetricSets, across all spans that contain a specified indexed tag or process.

MetricSets

MetricSets are metric time series (MTS) you can use to track the performance of specific metrics over time.

Default tags

The following tags are automatically indexed during ingestion by default depending on the metric:

  • URL name

  • operation

  • HTTP method and status code

  • custom event name

  • browser and version

  • OS name and version

  • city, region, country

Use cases for span tags

Use span tags to add additional context to existing spans (for example, page loads network requests). Adding custom tags helps you refine results and glean insights most pertinent to you. Tags are attributes of an event, such as the environment or the user associated with an existing action.

Here are some examples of what you can use as span tags:

  • Customer support tier or loyalty level

  • Internal geographic locations for facilities

  • Branch locations

Additionally, you can use custom workflow spans in RUM. Custom workflow spans capture specific, discrete occurrences or milestones that are not automatically tracked by the RUM agent. For more information, see Create workflow spans.

Add custom tags to Tag Spotlight

You need to be an admin to do this task. Follow these steps to add custom tags to Tag Spotlight:

  1. Add a span tag as explained in Create a span. To add attributes to the span, see RUM’s API Methods.

  2. Choose from the following ways to navigate to the MetricSets configuration page:

    • 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.

  3. Choose the tag you want to index to trigger the cardinality analyzer. If the cardinality check passes, select Add MetricSet and confirm with the check mark.

Troubleshooting

If the cardinality analysis fails, you may have exceeded your entitlements.

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 .