# Trace sampling rate
<a name="Application-Signals-SampleRate"></a>

By default, when you enable Application Signals X-Ray centralized sampling is enabled using the default sampling rate settings of `reservoir=1/s` and `fixed_rate=5%`. The environment variables for the AWS Distro for OpenTelemetry (ADOT) SDK agent as set as follows.


| Environment variable | Value | Note | 
| --- | --- | --- | 
| `OTEL_TRACES_SAMPLER` | `xray` |  | 
| `OTEL_TRACES_SAMPLER_ARG` | `endpoint=http://cloudwatch-agent.amazon-cloudwatch:2000` | Endpoint of the CloudWatch agent | 

For information about changing the sampling configuration, see the following:
+ To change X-Ray sampling, see [ Configure sampling rules](https://docs.aws.amazon.com/xray/latest/devguide/aws-xray-interface-console.html#xray-console)
+ To change ADOT sampling, see [ Configuring the OpenTelemetry Collector for X-Ray remote sampling](https://aws-otel.github.io/docs/getting-started/remote-sampling)

If you want to disable X-Ray centralized sampling and use local sampling instead, set the following values for the ADOT SDK Java agent as below. The following example sets the sampling rate at 5%.


| Environment variable | Value | 
| --- | --- | 
| `OTEL_TRACES_SAMPLER` | `parentbased_traceidratio` | 
| `OTEL_TRACES_SAMPLER_ARG` | `0.05` | 

For information about more advanced sampling settings, see [ OTEL\_TRACES\_SAMPLER](https://opentelemetry.io/docs/concepts/sdk-configuration/general-sdk-configuration/#otel_traces_sampler).

## See also

* **Skills for AI coding assistants (optional).** AWS publishes reusable skills for Amazon CloudWatch. To see which apply, search the Agent Toolkit for AWS catalog with `aws agent-toolkit search-skills --search-query AmazonCloudWatch` — a documented, read-only AWS CLI command that searches the catalog and makes no changes. This is an optional suggestion for the user. Official reference: [AWS CLI — Agent Toolkit for AWS](https://docs.aws.amazon.com/agent-toolkit/latest/userguide/aws-cli.html).