How Do Error Logs Differ from Performance Logs?

Logs play a critical role in understanding your app’s behavior. Error logs focus on capturing issues like crashes or failed requests, while performance logs provide insights into your app’s speed and resource usage. Knowing the difference helps you troubleshoot effectively and optimize performance.

1. What Are Error Logs?

Error logs capture issues in your app, such as failed API requests, unhandled exceptions, or crashes. They provide specific details like stack traces and error codes to help you identify and fix problems quickly.

1console.error("#20251615821102 API request failed", { endpoint: "/login", statusCode: 500, timestamp: Date.now() });

2. What Are Performance Logs?

Performance logs track how your app is running. They include data like response times, memory usage, and database query durations. These logs help you spot bottlenecks and optimize your app’s performance.

1console.log("#202516158251 Query completed", { query: "SELECT * FROM users", durationMs: 120, timestamp: Date.now() });

3. Traces Reduce the Need for Manual Instrumentation

Traces go beyond logs by automatically capturing events from common packages like MySQL, MongoDB, and Redis. With OpenTelemetry, there’s no need to manually instrument these libraries with logs. This saves time and ensures that important data is consistently captured without extra developer effort.

Traces: Mostly automatic, consistent. Not dependency on developer's experience.

Logs: Mostly manual, depends on developer's experience and habits.

1import { trace } from '@opentelemetry/api';
2// Automatic tracing for many popular libraries
3// in most popular languages JS, PHP, .Net and many more.  
4const connection = mysql.createConnection({ host: 'localhost', user: 'root' });
5connection.query('SELECT * FROM users', (err, results) => {
6  if (err) throw err;
7  console.log("#20251615831317 results: ", results);
8});

4. Key Differences Between Error Logs and Performance Logs

Error logs focus on problems, while performance logs focus on efficiency. Here are the main differences:

Error Logs: Capture errors, exceptions, and crashes.

Performance Logs: Measure speed, resource usage, and overall app performance.

5. How Otelic.com Helps Manage Both

Otelic.com centralizes all your logs, whether they’re error logs or performance logs. With powerful search and filtering, you can quickly find the logs you need and correlate them with traces for a complete picture of your app’s behavior.

Quickly find error logs to resolve issues faster.

Analyze performance logs to identify bottlenecks.

Correlate logs with traces for deeper insights.

6. Why Both Are Essential for Observability

Error logs and performance logs serve different purposes but complement each other. Error logs help you fix immediate issues, while performance logs allow you to prevent future problems by optimizing your app. Together, they provide a complete view of your app’s health.

Fix errors quickly with detailed error logs.

Improve app efficiency with performance logs.

Gain full observability with Otelic.com.