Application Performance and Usage Telemetry Analysis

Correlate Usage and Performance Telemetry

Understanding how your application behaves in production requires collecting and analyzing telemetry data. Azure Monitor and Application Insights work together to gather metrics and logs that show how users interact with your application and how well it performs. By studying this data, you can spot problems before they affect users and make informed decisions about improvements. The goal is to maintain service-level objectives, which are promises about how fast and reliable your application should be.

What Application Insights Collects

Application Insights gathers two main types of data: telemetry from your server-side code and telemetry from client-side web pages. On the server, it captures HTTP requests that come into your application, information about external services your code calls (like databases or storage), error logs called exceptions, and performance measurements like CPU and memory usage. It also allows developers to create custom events and metrics that track business-specific information, plus detailed trace logs that record what the code is doing step by step.

From the client side, Application Insights captures uncaught exceptions that occur in the user's browser, network requests the webpage makes, and information about the users themselves including their devices and browsing sessions. This combined view lets you see the full picture of how your application performs from the user's perspective.

Using Live Metrics and Application Map

Once you enable Application Insights, two tools help you monitor your application in real time. Live metrics show what's happening right now, updating continuously so you can diagnose problems as they occur. The Application map provides a visual representation of your application's structure, showing all the components and services that make up your system. This map highlights where bottlenecks or failures are happening, making it easier to identify which part of your application needs attention.

Analyzing Performance Metrics

To keep your application running smoothly, you need to track several key performance indicators. Request rates tell you how many users are accessing your application at any given time, while response times show how quickly the application answers those requests. Failure rates reveal how often requests result in errors. By comparing these metrics, you can identify when usage peaks coincide with performance problems, helping you understand whether increased traffic is causing slowdowns or failures.

You should also monitor dependency performance, which measures how long external services take to respond. If a database or API call is slow, it can drag down your entire application's performance. Finally, examining exceptions and logs helps you understand what specific errors are occurring and why, giving you the details needed to fix bugs and improve reliability.

Working with Trace Logs

Trace logs provide a breadcrumb trail of your application's activities, which is invaluable when investigating problems. To get the most from traces, integrate Application Insights with your logging framework (such as ILogger in .NET) so that trace messages flow automatically into your telemetry data. When analyzing traces, look at them alongside exception data to gain context about what was happening when an error occurred. Each log entry should include contextual identifiers like operation IDs, which link related log entries together and make it easier to follow the sequence of events leading to a problem.

Setting Up Availability Tests

To ensure your application remains accessible to users, configure availability tests that periodically check whether your endpoints are responding correctly. These tests run automatically from different geographic locations and alert you when an endpoint becomes unavailable or responds too slowly. By monitoring critical endpoints this way, you can detect and fix outages before most users even notice them.