Set Up Tracing

With tracing, 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.

Configure

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

• Setting a uniform sample rate for all transactions using the traces_sample_rate option in your SDK config to a number between 0 and 1. (For example, to send 20% of transactions, set traces_sample_rate 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 traces_sampler config option.

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

#include <sentry.h>

sentry_options_t *options = sentry_options_new();

+ // The native SDK currently only supports uniform sample rates.
+ sentry_options_set_traces_sample_rate(options, 0.2);

sentry_init(options);

Learn more about tracing options, how to use the tracesSampler function, or how to sample transactions.

Verify

Test out tracing by starting and finishing a transaction, which you must do so transactions can be sent to Sentry. Learn how in our Custom Instrumentation content.

While you're testing, set traces_sample_rate 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 traces_sample_rate value, or switch to using traces_sampler to selectively sample and filter your transactions, based on contextual data.

Next Steps