10+ Infosys Performance Test Engineer Interview Questions and Answers

Concurrent users and simultaneous users are often used interchangeably, but they have different meanings.

• Concurrent users refer to the number of users accessing the system at the same time.

• Simultaneous users refer to the number of users performing the same action at the same time.

• Concurrent users can perform different actions at the same time, while simultaneous users perform the same action.

• For example, if 100 users are accessing a website at the same time, they are concurre...read more

There are several types of graphs, including line, bar, pie, scatter, and area graphs.

• Line graphs show trends over time.

• Bar graphs compare data between different categories.

• Pie graphs show proportions of a whole.

• Scatter graphs show the relationship between two variables.

• Area graphs show the cumulative totals over time.

NFR sheet can be prepared by identifying the non-functional requirements and documenting them in a structured format.

• Identify the non-functional requirements such as performance, scalability, reliability, security, usability, etc.

• Document the requirements in a structured format such as a spreadsheet or a table.

• Include details such as the requirement description, acceptance criteria, priority, and any dependencies.

• Ensure that the requirements are measurable and testable.

• Review...read more

Pacing time is calculated by dividing the total number of transactions by the duration of the test.

• Pacing time is used to determine the rate at which virtual users should be generated during a performance test.

• It is calculated by dividing the total number of transactions by the duration of the test.

• For example, if the test is scheduled to run for 1 hour and the expected number of transactions is 10,000, the pacing time would be 6 seconds (3600 seconds / 10,000 transactions).

Rendezvous point is a synchronization point in load testing where multiple virtual users wait for each other before proceeding.

• Used in load testing to simulate real-world scenarios

• Ensures that all virtual users reach a certain point before continuing

• Helps in measuring the response time of the system under load

• Can be used to test scenarios like online auctions, where multiple users bid at the same time

IP Spoofing is a technique used to impersonate another device by changing the source IP address of a packet.

• IP Spoofing is commonly used in DDoS attacks to hide the attacker's identity.

• It can also be used to bypass access controls by impersonating a trusted device.

• IP Spoofing can be prevented by using firewalls and network intrusion detection systems.

3-tier architecture is a client-server architecture with three layers: presentation, application, and data storage.

• Presentation layer: User interface for interaction with the application

• Application layer: Business logic and processing of user requests

• Data storage layer: Storage and retrieval of data

• Each layer communicates with the layer above and below it

• Allows for scalability and separation of concerns

• Examples: Web applications, e-commerce sites, banking systems

SLA in performance testing refers to the agreed upon level of service that a system must meet in terms of response time, throughput, and other performance metrics.

• SLA stands for Service Level Agreement

• It defines the expected performance metrics that a system must meet

• SLAs are typically agreed upon between stakeholders and are used to measure the performance of a system

• Examples of SLAs include response time should be less than 2 seconds, throughput should be at least 100 trans...read more

Threads are lightweight processes within a process that can run concurrently. Thread groups are a collection of threads.

• Threads are independent sequences of execution within a process.

• Thread groups are used to organize and manage multiple threads together.

• Threads within a group can share resources and communicate with each other.

• Example: In performance testing, threads can simulate multiple users accessing a system concurrently.

I used Jmeter for its user-friendly interface, extensive features, and ability to simulate real-world scenarios.

• Jmeter has a user-friendly interface which makes it easy to create and execute performance tests.

• It offers a wide range of features for load testing, stress testing, and performance monitoring.

• Jmeter allows for the simulation of real-world scenarios, helping to identify performance bottlenecks and optimize system performance.

• It supports various protocols such as HTT...read more

Correlation in JMeter is the process of extracting dynamic values from server responses and passing them as inputs to subsequent requests.

• Correlation is important in performance testing to simulate real user behavior.

• It involves identifying and capturing dynamic values like session IDs, tokens, etc.

• These values are then extracted using regular expressions or built-in JMeter functions.

• The extracted values are stored in variables and used in subsequent requests to maintain sess...read more

Parameterization is the process of replacing hard-coded values in a test script with variables to make the script more dynamic and reusable.

• Parameterization helps in simulating real-world scenarios by varying input data during test execution.

• It allows for running the same test script with different sets of data without the need to modify the script each time.

• Common examples of parameterization include using CSV files, databases, or data tables to provide input values to the t...read more

Aggregate report is a summary of performance test results showing key metrics like average response time, throughput, error rate, etc.

• Aggregate report provides a high-level summary of performance test results

• It includes metrics like average response time, throughput, error rate, and percentiles

• Helps in identifying performance bottlenecks and areas for improvement

• Commonly used in tools like JMeter to analyze performance test results

View Result Tree is a listener in JMeter that displays the results of performance tests in a tree format.

• View Result Tree is used to view the response data, request and response headers, and other details of each sample in a performance test.

• It can be used to debug issues in the test script by analyzing the details of each request and response.

• View Result Tree can also be used to view and analyze the performance metrics such as response time, latency, and throughput.

• It is a u...read more

API testing is a type of software testing that involves testing APIs directly to ensure they meet functionality, reliability, performance, and security requirements.

• API testing involves testing the functionality, reliability, performance, and security of APIs.

• It focuses on verifying that the API meets the requirements specified in its design.

• API testing can be done manually or using automated tools.

• Examples of API testing tools include Postman, SoapUI, and JMeter.