Week 9 - Load Runner

What is LoadRunner and whats it’s purpose?

It’s used to simulate thousands of users interacting with an application simultaneously. It measures how systems behave under various load conditions, helping teams identify bottlenecks before they impact real users.

What are the four main components of LoadRunner?

1. Virtual User Generator (VuGen): Creates and edits test scripts by recording user interactions

2. Controller: The command center for designing and managing load test scenarios

3. Load Generators: Execute the actual virtual users and generate load on the system

4. Analysis: Processes raw test results into meaningful graphs, statistics, and reports

What is a Virtual user (VUser) in LoadRunner?

It simulates the actions of a real user interacting with an application. VUsers executes scripts recorded in VuGen, generating load on the system. Each VUser operates independently, maintaining its own session and data, allowing testers to simulate hundreds or thousands of concurrent users without needing real people.

What is the purpose of the Virtual User Generator (VuGen)?

It’s LoadRunner’s integrated development environment for creating, editing, and debugging performance test scripts. It records user interaction with applications and generates scripts that simulate those actions.

What is parameterization in LoadRunner and why is it important?

It replaces static (hardcoded) values with dynamic data, making scripts more realistic. Without parameterization, all virtual users would use identical data (same username, same search terms), creating unrealistic data.

What is correlation in LoadRunner?

Captures dynamic server-generated values (like session IDs, tokens, and timestamps) and replaces them with parameterized values for subsequent results.

What is ramp-up in load testing?

Gradual increase in the number of virtual users over time.

What key metrics would you analyze in a LoadRunner performance report?

• Response Time: Average, 90th percentile, standard deviation

• Throughput: Transactions per second (TPS), data throughput

• Error Rate: Percentage of failed transactions

• Hits per Second: Individual HTTP requests to the server

• Running VUsers: Concurrent users over time