Sampling using Javaagent

[itsmaneesh]

Hi,
Can you please let me know the steps to enable Sampling using Javaagent.
We were using Jaeger sampling (JAEGER_SAMPLER_TYPE, JAEGER_SAMPLING_PARAM variables) using OpenTracing earlier and now migrating to OpenTelemetry.

[trask]

hi @itsmaneesh, check out https://github.com/open-telemetry/opentelemetry-java/blob/main/sdk-extensions/autoconfigure/README.md#sampler

[itsmaneesh]

@trask I understand that OpenTelemetry expects the below properties for Sampling to take place:
OTEL_TRACES_SAMPLER
OTEL_TRACES_SAMPLER_ARG
Our requirement is to have Sampling strategy as [type: ratelimiting, param: 2.0] i.e. Sample request with the rate of 2 traces per second.
I couldn't find clear mapping for Sampler Types
like const, probabilistic, ratelimiting and remote details in the OpenTelemetry auto configure README)

So, Can you please clarify whether the below configuration works for our case:
OTEL_TRACES_SAMPLER = parentbased_traceidratio
OTEL_TRACES_SAMPLER_ARG = 2.0

Thank you.

[trask]

hi @itsmaneesh, if you are looking for a ratelimiting sampler, check out ConsistentRateLimitingSampler at https://github.com/open-telemetry/opentelemetry-java-contrib/tree/main/consistent-sampling

[itsmaneesh]

@trask Thank you for the input.
I have couple of follow up questions on this consistent-sampling:

1. ConsistentRateLimitingSampler seems to be sampling the spans per second as per targetSpansPerSecondLimit method param value.

   for e.g.: In our use case number of spans per request will vary. So, if we define targetSpansPerSecondLimit value as 5 then we
   would miss the spans if there are more than 5 spans per second and that would not give us the complete information.
   So, we are looking for a Rate limiting Sampling strategy that samples the traces per second so that we sample the number of
   traces and will have the complete spans information.

2. I couldn't come across a documentation that explains how to use this consistent-sampling project. Could you please guide me to a documentation that provide more insights to how to use this project.

[itsmaneesh]

@trask Can you please provide your clarifications to the above questions.
Thanks.

[itsmaneesh]

@trask Can you please provide clarifications to the above questions.