Load Testing Tutorial: What is? How to? (with Examples)
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Load Testing
Load Testing is a non-functional software testing process in which the performance of software application is tested under a specific expected load. It determines how the software application behaves while being accessed by multiple users simultaneously. The goal of Load Testing is to improve performance bottlenecks and to ensure stability and smooth functioning of software application before deployment.
Some extremely popular sites have suffered serious downtimes when they get massive traffic volumes. E-commerce websites invest heavily in advertising campaigns, but not in Load Testing to ensure optimal system performance, when that marketing brings in traffic.
Consider the following examples
Popular toy store Toysrus.com, could not handle the increased traffic generated by their advertising campaign resulting in loss of both marketing dollars, and potential toy sales.
An Airline website was not able to handle 10000+ users during a festival offer.
Encyclopedia Britannica declared free access to their online database as a promotional offer. They were not able to keep up with the onslaught of traffic for weeks.
Many sites suffer delayed load times when they encounter heavy traffic. Few Facts -
Most users click away after 8 seconds' delay in loading a page
$ 4.4 Billion Lost annually due to poor performance
Why Load Testing?
Load testing gives confidence in the system & its reliability and performance.
Load Testing helps identify the bottlenecks in the system under heavy user stress scenarios before they happen in a production environment.
Load testing gives excellent protection against poor performance and accommodates complementary strategies for performance management and monitoring of a production environment.
Goals of Load Testing:
Loading testing identifies the following problems before moving the application to market or Production:
Response time for each transaction
Performance of System components under various loads
Performance of Database components under different loads
Network delay between the client and the server
Software design issues
Server configuration issues like a Web server, application server, database server etc.
Hardware limitation issues like CPU maximization, memory limitations, network bottleneck, etc.
Load testing will determine whether the system needs to be fine-tuned or modification of hardware and software is required to improve performance.
Prerequisites of load testing:
The chief metric for load testing is response time. Before you begin load testing, you must determine -
Whether the response time is already measured and compared - Quantitative
Whether the response time is applicable to the business process - Relevant
Whether the response time is justifiable - Realistic
Whether the response time is achievable - Achievable
Whether the response time is measurable using a tool or stopwatch - Measurable
An environment needs to be set up before starting the load testing:
Hardware Platform
Software Configuration
Server Machines
Processors
Memory
Disk Storage
Load Machines configuration
Network configuration
Operating System
Server Software
Strategies of load Testing:
There are many numbers of ways to perform load testing. Following are a few load testing strategies- The load testing process can be briefly described as below -
