Set Up

With performance monitoring, Sentry tracks your software performance, measuring metrics like throughput and latency, and displaying the impact of errors across multiple systems. Sentry captures distributed traces consisting of transactions and spans, which measure individual services and individual operations within those services. Learn more about our model in Distributed Tracing.

Enable Tracing

To automatically send traces, you must configure SentryTracingFilter in web.xml for Servlet applications configured with XML, or WebApplicationInitializer for Servlet applications configured with Java code:

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import io.sentry.spring.tracing.SentryTracingFilter;
import javax.servlet.Filter;
import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;

public class AppInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {
  // ...
  @Override
  protected Filter[] getServletFilters() {
    return new Filter[] {new SentryTracingFilter()};
  }
}

Configure the Sample Rate

Once you configure the sample rate, tracing will be enabled in your app. Set the sample rate for your transactions by either:

  1. Setting a uniform sample rate for all transactions using the tracesSampleRate option in your SDK config to a number between 0 and 1. (For example, to send 20% of transactions, set tracesSampleRate to 0.2.)
  2. Controlling the sample rate based on the transaction itself and the context in which it's captured, by providing a function to the tracesSampler config option.

The two options are meant to be mutually exclusive. If you set both, tracesSampler will take precedence.

Or alternatively:

Configure sample rate in sentry.properties:

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traces-sample-rate=0.3

Or through providing a bean of type SentryOptions#TracesSamplerCallback:

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import io.sentry.SentryOptions.TracesSamplerCallback;
import io.sentry.SamplingContext;
import org.springframework.stereotype.Component;

@Component
class CustomTracesSamplerCallback implements TracesSamplerCallback {
  @Override
  public Double sample(SamplingContext context) {
    CustomSamplingContext customSamplingContext = context.getCustomSamplingContext();
    if (customSamplingContext != null) {
      HttpServletRequest request = (HttpServletRequest) customSamplingContext.get("request");
      // return a number between 0 and 1 or null (to fallback to configured value)
    } else {
      // return a number between 0 and 1 or null (to fallback to configured value)
    }
  }
}

Without sampling, automatically-captured transactions can add up quickly. The Spring integration, for example, will send a transaction for every request made to the server.

Learn more about how the options work in Sampling Transactions.

Verify

Verify that performance monitoring is working correctly by using our automatic instrumentation or by starting and finishing a transaction using custom instrumentation.

While you're testing, set tracesSampleRate to 1.0, as that ensures that every transaction will be sent to Sentry.

Once testing is complete, we recommend lowering this value in production by either lowering your tracesSampleRate value, or switching to using tracesSampler to dynamically sample and filter your transactions.

Connecting Services

If you are also using Performance Monitoring for JavaScript, depending on where your request originates, you can connect traces:

  1. For requests that start in your backend, by adding a meta tag in your HTML template that contains tracing information.
  2. For requests that start in JavaScript, by the SDK setting a header on requests to your backend.

Otherwise, backend services with Performance Monitoring connect automatically.

Next Steps:

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