Advanced Guide to Load Testing

This guide is designed for those who are already familiar with load testing but are looking to dive deeper into its concepts, methods, and benefits. We’ll cover everything from the basic definitions to advanced techniques, the challenges involved, and how RadView’s WebLOAD can help streamline your load testing processes.

What is Load Testing?

Load testing is a type of non-functional software testing that measures a system’s performance under an increased user volume to ensure it can handle expected traffic. It involves evaluating the system’s behavior and functionality using various metrics and parameters such as response time, throughput, server health, and stability.

When it comes to non-functional software testing, load testing is typically the first thing that comes to mind. Load testing measures the response of a system under an increased user volume in order to verify it can handle an expected traffic of users. To test your system’s behavior and functionality you use various measurements and parameters such as response time, throughput, servers’ health and stability.

But what does an “increased user load” mean? This will vary significantly depending on the application and context. Google may expect millions of users searching for data in parallel and may require that its system return results in less than 0.5 seconds.

A small local bank, on the other hand, may only be required to serve 1000 users in parallel with a 3-seconds login. And an eCommerce site may have another set of requirements for handling the checkout process of thousands of users.

Put differently, load testing goals (which are often not given enough thought), will depend on the context and specific business.

By performing load testing, you can identify potential performance bottlenecks before your new features go live. Besides identifying bottlenecks it can provide you with the actual picture of how your systems handle under high load and pressure, as we are all familiar that in today’s world there isn’t any second chance for users’ impression. This type of testing can be even more effective when you implement it with a Shift Right mentality.

Measurements of Load Testing

In load testing, several key measurements are essential to assess the system’s performance:

Response Time: The time taken by the system to respond to user requests.
Throughput: The amount of data processed by the system in a given time frame.
Server Health and Stability: Monitoring the servers’ performance, including CPU, memory usage, and error rates.

How is Load Testing Done?

Traditionally, load testing was manual, posing challenges in producing repeatable results and measurable stress levels. This led to the development of proprietary tools requiring ongoing maintenance. While open-source tools addressed some issues, enterprise-level commercial tools like WebLOAD offer the best solutions for automating load testing pipelines.

Download the eBook – Load Testing Buyer’s Guide

How to Conduct a Load Test

There are 5 main steps for conducting a load test:

Defining Goals: Identify specific metrics such as expected response times, user volume, and peak load scenarios.
Setting a Load Test Environment: Create a test environment that mirrors the production environment, including machine profiles, network architecture, load balancers, and databases.
Creating Load Scenarios: Develop scenarios by recording user activity or scripting, incorporating validation points, transactions, and measurements.
Running Tests: Execute scenarios under different conditions to simulate real-life usage, varying user numbers, locations, and browsers.
Analyzing Results: Interpret data related to transactions, errors, hits, response times, and server performance to identify bottlenecks and issues.

Read our guide for How to Do a Load Test with WebLOAD for a detailed look at how RadView’s WebLOAD specifically helps you conduct load testing.

Data Collection

Load testing collects various data types, including:

Transaction Metrics: Details of user transactions and their performance.
Error Rates: Frequency and types of errors encountered during testing.
System Metrics: CPU, memory, and network usage statistics. Analyzing this data helps in understanding system behavior and pinpointing performance issues.

Load Testing Requirements

Implementing load testing usually requires:

Quantitative Benchmarks: Establishing response time benchmarks and performance comparisons.
Performance SLAs: Defining Service Level Agreements that need to be met.
Cross-Department Collaboration: Aligning expectations and goals across different teams.
Technical Breakdown: Ensuring the goals are achievable with the current technical setup.
Ongoing Monitoring: Setting up continuous monitoring and documentation processes.

Top Benefits of Load Testing

Eliminates Performance Issues: Identifies bottlenecks before reaching production, ensuring robust and dynamic applications.
Scalability: Helps prepare for peak loads by testing varying levels of application load.
Smoother Development: Improves productivity and reduces post-production issues by testing early in the development process.

Challenges of Load Testing

Load testing comes with its own set of challenges, including:

Complexity: Setting up realistic test environments and scenarios.
Resource Intensive: Requires significant computational and human resources.
Data Analysis: Managing and interpreting large volumes of performance data.

The Process of Running Load Testing

While complete books are devoted to the process and methodology of load testing planning and executing, here are the very basic steps in the process.

1. Defining goals

This is the first, important, and often forgotten step of the load testing. Unlike functional or regression testing where pass/fail results are definite, in load testing the results are much less clear cut, and are open to interpretation as to whether they are good or bad.

Load testing goals may include a wide range of metrics such as the expected response time, the number of users each activity will support, what should happen in peak time, the number of many mobile users supported, etc.

2. Setting a load test environment

An important part of running load tests is building a solid test environment that accurately replicates the real production environment. This includes issues such as machine profiles and configuration, the network architecture, load balancers, firewalls, databases, etc. For more info on this you can read our tips for building a load test environment.

3. Creating load scenarios

Building load scenarios is done by either recording user activity, scripting, or in most cases a combination of both. Load test scenarios will include validation points, transactions and measurements.

4. Running tests

Once you’ve setup test scenarios, you execute them using different conditions to simulate real-life conditions, based on your goals. For example, run scenarios using different number of users, from different location or using different browsers. Different frameworks can be used for running load testing scripts, such as Selenium.

5. Analyzing results

Results analysis involved the interpretation of data collected during test runs. This includes data related to transactions, errors, hits, responses times of transactions, pages, components, and servers performance measurements.

The heaps of data collected are typically what make results analysis challenging. The process of analysis is typically iterative, where you modify different test settings and re-run scenarios in order to narrow down problems and identify the root-cause of issues. A methodological and well-documented process that is planned and based on pre-defined goals can save lots of time.

Troubleshooting: Dealing with Load Testing Issues

To effectively troubleshoot load testing issues:

Isolate Problems: Methodically identify and isolate the root causes of performance bottlenecks.
Iterative Testing: Continuously refine and re-run test scenarios to address identified issues.
Comprehensive Documentation: Maintain detailed documentation to track changes and their impacts.

Types of Load Testing

There are a few different types of load tests, aimed at testing different aspects or conditions:

‘Classic’ load testing: Typically tests the system to verify that it can provide certain response times for a certain volume of users.
Stress testing: Tests how the system behaves in extreme conditions after it reached its defined requirement as defined by the load testing. Extreme conditions may include machines with less memory than expected, more users than expected, different CPU, or other configurations.
Capacity testing: Capacity is a specific type of stress testing, which helps identify the maximum number of users the system can serve.
Soak testing: Tests how the system behaves when running for a long duration (for example, several days) after it reached its defined requirements as defined by the load testing.

For a more in-depth discussion on each type and when it should be used, read our blog on 4 Types of Load Testing.

Frequently Asked Questions

When is Load Testing Done?

Load testing is typically performed at the end of a release cycle, just before pushing the software live. However, integrating load testing earlier in the development process helps identify and resolve issues sooner, reducing costs and avoiding delays.

Is Load Testing the Same as Performance Testing?

Performance testing is a broader term that includes various types of testing, including load testing. Load testing specifically simulates a large volume of user activities to evaluate system performance.

Is Load Testing the Same as Stress Testing?

A quick clarification – load testing mainly focuses on finding and pinpointing problems and bottlenecks caused by fluctuating workloads while examining performance when traffic is increased to predetermined levels. On the other hand, stress testing is all about finding the breaking point of the website or infrastructure.

RadView’s WebLOAD: Answering Your Load Testing Needs

RadView’s WebLOAD is designed to address the complexities of load testing, offering robust tools for creating realistic test environments, automating test scenarios, and providing detailed analytics. WebLOAD helps you ensure your applications can handle peak traffic smoothly and efficiently.

Learn more about WebLOAD and how it can enhance your load testing processes by Scheduling a Demo.