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Application sampling

If you notice performance issues after you instrument your application with a Contrast agent, consider enabling application sampling.

When enabled, sampling selectively turns the agent off for a short amount of time, based on uniquely identified requests. If an application is responding to the same request often, the agent doesn't need to analyze it multiple times. This behavior ensures that the agent analyzes code only when it's in different contexts.

Best practice: Consider enabling sampling when you run long-duratiion tests in a test environment. Due to the high-level of activity that occurs in this situation, enabling sampling can improve application performance.

If sampling is appropriate for your environment, enable it as part of your server configuration.

How sampling works

  1. If the Contrast agent sees the same URL being called multiple times, it analyzes the URL based on the the number of times specified in the Baseline setting.

  2. Afterwards, if the Contrast agent continues to see the same URL, it only checks the URL based on the Frequency setting.

  3. Contrast retains samples for the number of seconds specified for the Window setting. After the time specified for the Window setting elapses, Contrast analyzes the URL again, according to the Baseline setting.