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.

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 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.)
  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.

Performance Monitoring is available for our updated Ruby SDK (sentry-ruby, not sentry-raven).

Copied
Sentry.init do |config|
  # set a uniform sample rate between 0.0 and 1.0
  config.traces_sample_rate = 0.2

  # or control sampling dynamically
  config.traces_sampler = lambda do |sampling_context|
    # sampling_context[:transaction_context] contains the information about the transaction
    # sampling_context[:parent_sampled] contains the transaction's parent's sample decision
    true # return value can be a boolean or a float between 0.0 and 1.0
  end
end

Learn more about how the options work in Sampling 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.

Verify that performance monitoring is working correctly by setting traces_sample_rate 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 traces_sample_rate value, or switching to using traces_sampler to dynamically sample and filter your transactions.

Next Steps:

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