Use ThreadLocalRandom for improved concurrency.
MODIFY
dd-trace-ot/src/main/java/datadog/trace/common/sampling/RateByServiceSampler.java
dd-trace-ot/src/main/java/datadog/trace/common/sampling/RateByServiceSampler.java
@@ -8,6 +8,7 @@ import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
+import java.util.concurrent.ThreadLocalRandom;
import lombok.extern.slf4j.Slf4j;
/**
@@ -122,7 +123,7 @@ public class RateByServiceSampler implements Sampler, ResponseListener {
@Override
public boolean doSample(final DDSpan span) {
- final boolean sample = Math.random() <= sampleRate;
+ final boolean sample = ThreadLocalRandom.current().nextFloat() <= sampleRate;
log.debug("{} - Span is sampled: {}", span, sample);
return sample;
}

Use ThreadLocalRandom for improved concurrency.