IMPORTANT: No additional bug fixes or documentation updates will be released for this version. For the latest information, see the current release documentation.
« Configure head-based sampling OpenTelemetry integration »
Elastic Docs › ›Elastic APM features ›Transaction sampling

Configure tail-based sampling

edit

Configure tail-based sampling

edit

Enable tail-based sampling in the APM integration settings. When enabled, trace events are mapped to sampling policies. Each sampling policy must specify a sample rate, and can optionally specify other conditions. All of the policy conditions must be true for a trace event to match it.

Trace events are matched to policies in the order specified. Each policy list must conclude with a default policy — one that only specifies a sample rate. This default policy is used to catch remaining trace events that don’t match a stricter policy. Requiring this default policy ensures that traces are only dropped intentionally. If you enable tail-based sampling and send a transaction that does not match any of the policies, APM Server will reject the transaction with the error no matching policy.

Example configuration

edit

This example defines three tail-based sampling polices:

- sample_rate: 1 
  service.environment: production
  trace.name: "GET /very_important_route"
- sample_rate: .01 
  service.environment: production
  trace.name: "GET /not_important_route"
- sample_rate: .1

Samples 100% of traces in production with the trace name "GET /very_important_route"

Samples 1% of traces in production with the trace name "GET /not_important_route"

Default policy to sample all remaining traces at 10%, e.g. traces in a different environment, like dev, or traces with any other name

Configuration reference

edit

Top-level tail-based sampling settings:

Enable Tail-based sampling

(bool) Enable and disable tail-based sampling.

Default: false

Interval

(duration) Synchronization interval for multiple APM Servers. Should be in the order of tens of seconds or low minutes.

Default: 1m

Policies

([]policy) Criteria used to match a root transaction to a sample rate. Order is important; the first policy on the list that an event matches is the winner. Each policy list must conclude with a default policy that only specifies a sample rate. The default policy is used to catch remaining trace events that don’t match a stricter policy.

Required when tail-based sampling is enabled.

Policy settings:

Sample rate

sample_rate

(int) The sample rate to apply to trace events matching this policy. Required in each policy.

Trace name

trace.name

(string) The trace name for events to match a policy.

Trace outcome

trace.outcome

(string) The trace outcome for events to match a policy. Trace outcome can be success, failure, or unknown.

Service name

service.name

(string) The service name for events to match a policy.

Service Environment

service.environment

(string) The service environment for events to match a policy.
« Configure head-based sampling OpenTelemetry integration »