Transaction_sample_rate minimun value allowed

Elastic Observability APM
1

Hello Everyone !

I would like to know if someone knows the minimum value allowed to set for the transaction_sample_rate property.
We have a service with high traffic load and we would like to set this value to 0.0002.
But when we reduce this value (is the 10% of the previous value setup) the amount of data ingested still remains the same, it seems the new config is not applied or is skipped by the apm-agent (java).

ElasticAPM stack version: 7.1.0
APM Java Agent version: 1.9.0

Is possible this property has a minimum which cannot be reduced?

Any help will be welcomed :slight_smile:

Thanks in advance,
Kr
Aitor

2

Hi and thanks for your question.

The catch is that we currently store transactions even if they are not sampled. I assume that's probably the bulk of whats in your indices. Only the spans for non-sampled transaction are omitted. We need this to calculate accurate percentiles and request per minute metrics.

However, we are currently investigating ways to aggregate the data on the agents or the APM Server. See also https://github.com/elastic/apm/issues/104

Felix