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Summary Metrics

Summary metrics are data related to entities that describes how certain parameters are behaving based the on the available telemetry.

We recommend to add a maximum of 10 metrics per entityType.

Defining summary metrics

Summary metrics are defined in a map where each key is a camel-case name that defines the intention of the metric:

memoryUsage:
  title: "A title explaining what the user is seeing"
  unit: PERCENTAGE
  query:
    select: average(host.memoryUsagePercent)
    from: Metric
    where: "tags.environment = 'production'"
    eventId: entity.guid

A summary metric can be either an NRDB-query-based metric, a Tag metric (summary tag), or a Derived metric, depending on the source of the information.

For this reason, exactly one of the query, tag and derive configuration needs to be provided. If less or more than one of them is found, the metric definition will not be valid.

Name Type Description
title String The human-readable name of the metric
unit Metric Unit The unit of the metric
query NRDB Query The configuration for an NRDB-query-based metric
tag Tag The configuration for a tag metric
derive Derive String The string to define a derived metric

Metric Unit

The unit of the metric must be a string with one of the following values:

  • REQUESTS_PER_SECOND
  • PAGES_PER_SECOND
  • MESSAGES_PER_SECOND
  • OPERATIONS_PER_SECOND
  • COUNT
  • SECONDS
  • PERCENTAGE
  • BITS
  • BYTES
  • BITS_PER_SECOND
  • BYTES_PER_SECOND
  • HERTZ
  • APDEX
  • TIMESTAMP
  • STRING

NRDB Query

The query map contains the information that is used to define a NRDB-query-based metric:

Name Type Description
from String A NRDB event, e.g. SystemSample, or Metric
select String What has to be selected from the given NRDB event, e.g count(*)
where String An optional NRQL filter, e.g. foo = 'bar'
eventId String The event attribute you want to facet and filter for, e.g. entity.guid

Tag

Name Type Description
key String The tag key you want to fetch the corresponding value for, e.g. providerAccountName

Derive string

The derive string can be used to derive a summary metric out of others. It is possible to reference other metrics using @metricName. Metrics can be added, subtracted, multiplied and divided by other metrics or numbers.

Example:

(@metricA * 100) / (@metricB + @metricC)

If a derive metric references a metric that does not exist, it will result in an error. If a derive metric references a metric whose value is null, its value will be null too. E.g.

@metricA + @metricB + 100

If either metricA or metricB is null, the value of the derived metric will be null too.

Aside from normal mathematical operations, the || (or) operator can be used, which returns the value of the first metric that has a value different than null. e.g.

@metricA || 10

It returns the value of metricA if it's not null, 10 otherwise.