Docs » Analyze services with span tags and MetricSets in Splunk APM » Learn about MetricSets in APM

Learn about MetricSets in APM πŸ”—

MetricSets are key performance indicators, like request rate, error rate, and request duration, that are calculated from traces and spans in Splunk APM. There are 2 categories of MetricSets: Troubleshooting MetricSets (TMS), used for high-cardinality troubleshooting, and Monitoring MetricSets (MMS), used for real-time monitoring. MetricSets are similar to the metric time series (MTS) used in Splunk Infrastructure Monitoring to populate charts and generate alerts. See Metric time series to learn more. MetricSets are MTS that are specific to Splunk APM.

Troubleshooting MetricSets πŸ”—

Troubleshooting MetricSets (TMS) are metric time series (MTS) you can use for troubleshooting high-cardinality identities in APM. You can also use TMS to make historical comparisons across spans and workflows.

Splunk APM indexes and generates Troubleshooting MetricSets for several span tags by default. For more details about each of these tags, see Default indexed span tags in APM. You can’t modify or stop APM from indexing these span tags.

You can also create custom TMS by indexing additional span tags and processes. To learn how to index span tags and processes to generate new Troubleshooting MetricSets, see Index span tags to generate Troubleshooting MetricSets.

Available TMS metrics πŸ”—

Every TMS generates the following metrics, known as request, error, and duration (RED) metrics. RED metrics appear when you select a service in the service map. See Scenario: Kai investigates the root cause of an error with the Splunk APM service map to learn more about using RED metrics in the service map.

  • Request rate

  • Error rate

  • Root cause error rate

  • p50, p90, and p99 latency

The measurement precision of Troubleshooting MetricSets is 10 seconds. Splunk APM reports quantiles from a distribution of metrics for each 10-second reporting window.

Use TMS within Splunk APM πŸ”—

TMS appear on the service map and in Tag Spotlight. Use TMS to filter the service map and create breakdowns across the values of a given indexed span tag or process.

See View dependencies among your services in the service map and Analyze service performance with Tag Spotlight.

TMS retention period πŸ”—

Splunk Observability Cloud retains TMS for the same amount of time as raw traces. By default, the retention period is 8 days.

For more details about Troubleshooting MetricSets, see Reference and best practices for span tags and Troubleshooting MetricSets.

Monitoring MetricSets πŸ”—

Monitoring MetricSets (MMS) are metric time series (MTS) that power the real-time monitoring capabilities in Splunk APM, including charts and dashboards. MMS power the APM landing page and the dashboard view. MMS are also the metrics that detectors monitor to generate alerts.

MMS are available for a specific endpoint or for the aggregate of all endpoints in a service.

Endpoint-level MMS reflect the activity of a single endpoint in a service, while service-level MMS aggregate the activity of all of the endpoints in the service. MMS are limited to spans where the span.kind has a value of SERVER or CONSUMER.

Spans might lack a kind value, or have a different kind value, in the following situations:

  • The span originates in self-initiating operations or inferred services

  • An error in instrumentation occurs.

In addition to the following default MMS, you can create custom MMS. See Generate a Monitoring MetricSet with a custom dimension.

Available default MMS metrics and dimensions πŸ”—

MMS are available for the following APM components:

  • service.request

  • spans

  • traces

  • workflows (Workflow metrics are created by default when you create a Business Workflow. Custom MMS are not available for Business Workflows.)

Each MMS includes 6 metrics for each component. For histogram MMS, there is a single metric for each component. Use the histogram functions to access the specific histogram bucket you want to use.

For each metric, there is 1 metric time series (MTS) with responses sf_error: true or sf_error: false.

Description

MMS

Histogram MMS

Request count

<component>.count

<component> with a count function

Minimum request duration

<component>.duration.ns.min

<component> with a min function

Maximum request duration

<component>.duration.ns.max

<component> with a max function

Median request duration

<component>.duration.ns.median

<component> with a median function

Percentile request duration

<component>.duration.ns.p90

<component> with a percentile function and a percentile value

Percentile request duration

<component>.duration.ns.p99

<component> with a percentile function and a percentile value

Each MMS has a set of dimensions you can use to monitor and alert on service performance.

Service dimensions πŸ”—

  • sf_environment

  • deployment.environment - This dimension is only available for histogram MMS.

  • sf_service

  • service.name - This dimension is only available for histogram MMS.

  • sf_error

Span dimensions πŸ”—

  • sf_environment

  • deployment.environment - This dimension is only available for histogram MMS.

  • sf_service

  • service.name - This dimension is only available for histogram MMS.

  • sf_operation

  • sf_kind

  • sf_error

  • sf_httpMethod, where relevant

Trace dimensions πŸ”—

  • sf_environment

  • deployment.environment - This dimension is only available for histogram MMS.

  • sf_service

  • service.name - This dimension is only available for histogram MMS.

  • sf_operation

  • sf_httpMethod

  • sf_error

Workflow dimensions πŸ”—

Workflow metrics and dimensions are created by default when you create a Business Workflow.

  • sf_environment

  • deployment.environment - This dimension is only available for histogram MMS.

  • sf_workflow

  • sf_error

Use MMS within Splunk APM πŸ”—

Use MMS for alerting and real-time monitoring in Splunk APM. You can create charts, dashboards, and alerts based on Monitoring MetricSets.

Task

Documentation

Create charts

Create charts in Splunk Observability Cloud

Create dashboards

Create and customize dashboards

Create an alert

Configure detectors and alerts in Splunk APM

Monitor services in APM dashboards

Track service performance using dashboards in Splunk APM

MMS retention period πŸ”—

Splunk Observability Cloud stores MMS for 13 months by default.

Comparing Monitoring MetricSets and Troubleshooting MetricSets πŸ”—

Because endpoint-level and service-level MMS include a subset of the TMS metrics, you might notice that metric values for a service are different depending on the context in Splunk APM. This is because MMS are the basis of the dashboard view and MMS can only have a kind of SERVER or CONSUMER. In contrast, TMS are the basis of the troubleshooting and Tag Spotlight views and TMS aren’t restricted to specific metrics.

For example, values for checkout service metrics displayed in the host dashboard might be different from the metrics displayed in the service map because there are multiple span kind values associated with this service that the MMS that power the dashboard don’t monitor.

To compare MMS and TMS directly, restrict your TMS to endpoint-only data by filtering to a specific endpoint. You can also break down the service map by endpoint.