Set Up Performance

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.

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:

import io.sentry.spring.tracing.SentryTracingFilter;
import javax.servlet.Filter;

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

First, enable tracing and configure the sampling rate for transactions. Set the sample rate for your transactions by either:

  • 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.)
  • 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

# Set traces_sample_rate to 1.0 to capture 100%
# of transactions for performance monitoring.
# We recommend adjusting this value in production.

Or through providing a bean of type SentryOptions#TracesSamplerCallback:

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

class CustomTracesSamplerCallback implements TracesSamplerCallback {
  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 performance monitoring options, how to use the tracesSampler function, or how to sample transactions.

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, you may want to set a lower tracesSampleRate value, or switch to using tracesSampler to selectively sample and filter your transactions, based on contextual data.

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