40+ Performance Tester Interview Questions and Answers

Answers to questions related to Performance Testing using JMeter

• Assertion in JMeter is used to validate the response of a request

• JMeter supports various protocols like HTTP, FTP, JDBC, etc.

• Hits per second is the number of requests sent to the server in a second

• Hits per second may become constant due to server limitations or network issues

• Sync testing involves waiting for a response before sending the next request, while async testing sends requests without waiting for a respo...read more

Yes

• During load testing of a web application, memory usage gradually increased over time

• Identified the memory leak by monitoring memory consumption using performance testing tools

• Investigated the code and found a section where objects were not being properly released

• Fixed the memory leak by implementing proper object disposal and memory management techniques

Memory leak is a software issue where allocated memory is not released, leading to memory consumption and performance degradation.

• Memory leak occurs when a program fails to deallocate memory that is no longer needed.

• It can happen due to programming errors like not freeing allocated memory or losing references to it.

• Memory leaks can cause the program to consume excessive memory, leading to performance issues and crashes.

• To handle memory leaks, tools like profilers can be used ...read more

Run time setting parameters are values that can be set during test execution to control the behavior of the test.

• Run time setting parameters are used to modify the behavior of the test during execution.

• They can be used to simulate different user loads, network conditions, and other variables.

• Examples include setting the number of virtual users, the duration of the test, and the think time between requests.

To split a string into multiple strings and assign them to an array, use the split() method in JavaScript.

• Use the split() method with the delimiter as an argument to split the string into an array of substrings.

• Assign the resulting array to a variable to access the individual substrings.

• Example: var str = 'apple,banana,orange'; var arr = str.split(','); console.log(arr); // ['apple', 'banana', 'orange']

Think time is the time taken by a user to think and perform an action, while pacing is the time interval between two consecutive user actions.

• Think time is the time taken by a user to read and understand the content on the screen before performing an action.

• Pacing is the time interval between two consecutive user actions, which is used to simulate real-world user behavior.

• Think time is used to simulate the time taken by a user to think and perform an action, while pacing is u...read more

Non-functional testing is the process of testing the performance, reliability, and usability of a system.

• Identify the non-functional requirements

• Design test scenarios and test cases

• Execute tests and collect data

• Analyze the results and report findings

• Repeat the process until the system meets the non-functional requirements

The challenge I am facing while scripting is identifying and handling dynamic elements.

• Dynamic elements such as timestamps and session IDs require unique handling

• Identifying and correlating dynamic values across multiple requests can be time-consuming

• Using regular expressions and functions can help in handling dynamic elements

Identify, replicate, and analyze the bug using logs, tools, and collaboration for resolution.

• Gather detailed information about the bug from users or monitoring tools.

• Check logs and metrics to identify patterns or anomalies related to the bug.

• Attempt to reproduce the bug in a controlled environment using the same conditions.

• Use performance testing tools (e.g., JMeter, LoadRunner) to simulate the production load.

• Collaborate with development and operations teams to understand th...read more

Identify checkout issues in Ecommerce by analyzing logs, monitoring performance, and conducting user feedback sessions.

• Check server logs for error messages during the checkout process.

• Use performance monitoring tools (e.g., JMeter, LoadRunner) to simulate user load and identify bottlenecks.

• Conduct user testing sessions to gather feedback on the checkout experience.

• Analyze network requests using browser developer tools to identify slow responses or failed requests.

• Review datab...read more

Parameters in result table are the values that are measured during performance testing.

• Parameters can include response time, throughput, error rate, and resource utilization.

• These values are used to analyze the performance of the system under test.

• They can be compared against performance requirements or industry benchmarks.

• Parameter values can be displayed in graphs or charts for easy analysis.

• Examples of parameter values include average response time, maximum throughput, and...read more

STLC outlines testing phases, while Bug Life Cycle tracks defect status from discovery to resolution.

• STLC consists of phases: Requirement Analysis, Test Planning, Test Case Design, Test Environment Setup, Test Execution, and Test Closure.

• Example of STLC: In Test Execution, testers run test cases and log defects found during testing.

• Bug Life Cycle includes stages: New, Assigned, Open, Fixed, Retested, and Closed.

• Example of Bug Life Cycle: A bug reported as 'New' is assigned to...read more

Deadlock is a situation in computing where two or more processes cannot proceed because each is waiting for the other to release resources.

• Occurs in multi-threaded environments where processes hold resources and wait for others.

• Example: Process A holds Resource 1 and waits for Resource 2, while Process B holds Resource 2 and waits for Resource 1.

• Can lead to system performance degradation and unresponsiveness.

• Deadlock detection and prevention strategies include resource alloca...read more

Performance bottleneck can occur in various areas of an application.

• Database queries and indexing

• Network latency and bandwidth

• CPU and memory usage

• Code inefficiencies and poor algorithms

• Third-party integrations

• Hardware limitations

• User load and concurrency

• Application architecture

• Caching and session management

• Security measures

• External factors such as weather or power outages

Use JMeter to send post data from a file

• Use CSV Data Set Config to read data from a file

• Add HTTP Request sampler to send post data

• Reference variables from CSV file in HTTP Request body

Authentication verifies identity; authorization determines access rights in APIs.

• Authentication is the process of verifying who a user is (e.g., logging in with a username and password).

• Authorization determines what an authenticated user can do (e.g., a user can view their own data but not others').

• Example of authentication: Using OAuth tokens to log in to an API.

• Example of authorization: Role-based access control (RBAC) where only admins can access certain endpoints.

As a Performance Tester using JMeter, I design, execute, and analyze performance tests to ensure application reliability and scalability.

• Designing test plans: Create comprehensive test plans that outline the performance testing strategy, including user scenarios and load profiles.

• Configuring test elements: Set up thread groups, samplers, listeners, and assertions to simulate user behavior and measure performance metrics.

• Executing tests: Run performance tests under various loa...read more

RTM (Requirements Traceability Matrix) ensures all requirements are covered in testing, linking them to test cases.

• RTM is a document that maps and traces user requirements with test cases.

• It is prepared at the beginning of the project, during the requirements gathering phase.

• RTM helps in identifying any missing requirements or test cases.

• For example, if a requirement states 'User must be able to log in', the RTM will link this to the corresponding test case.

• It is updated thro...read more

Agile is an iterative and incremental approach to software development that emphasizes flexibility and customer satisfaction.

• Agile involves breaking down the project into smaller, manageable chunks called sprints.

• Each sprint involves planning, designing, coding, testing, and reviewing the work done.

• The team works closely with the customer to ensure that the product meets their needs.

• Agile encourages collaboration, communication, and continuous improvement.

• Popular Agile method...read more

I have strong technical skills in performance testing through hands-on experience with various tools and technologies.

• Proficient in using performance testing tools such as JMeter, LoadRunner, and Gatling

• Experience in designing and executing performance test scenarios to identify bottlenecks and optimize system performance

• Knowledge of performance monitoring tools like New Relic and AppDynamics

• Ability to analyze test results and provide recommendations for performance improveme...read more

Functional testing verifies software features, while non-functional testing assesses performance, usability, and reliability.

• Functional testing focuses on specific functionalities of the software, e.g., login/logout features.

• Non-functional testing evaluates system performance under load, e.g., stress testing.

• Functional testing checks if the application behaves as expected, e.g., validating calculations in a financial app.

• Non-functional testing assesses user experience, e.g., ...read more

Pacing in performance testing refers to controlling the rate at which virtual users execute transactions to simulate real-world user behavior.

• Pacing helps in simulating realistic user behavior by controlling the rate of transactions executed by virtual users.

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

• For example, if a test is scheduled to run for 1 hour and 600 transactions need to be executed, the pacing would be 1 trans...read more

My expected CTC is based on industry standards, my experience, and the value I bring to the team.

• Research market rates for Performance Testers in my region.

• Consider my years of experience and expertise in tools like JMeter and LoadRunner.

• Factor in the complexity of projects I've handled, such as high-traffic applications.

• Align my expectations with the company's budget and growth potential.

JMeter offers various features for performance testing, including load generation, protocol support, and detailed reporting.

• Load Testing: Simulate multiple users to test application performance under heavy load, e.g., testing a web application with 1000 concurrent users.

• Protocol Support: Supports various protocols like HTTP, FTP, JDBC, and more, allowing testing of diverse applications.

• Distributed Testing: Enables load generation from multiple machines to simulate a large num...read more

CPU bottleneck can be handled by optimizing code, upgrading hardware, and load balancing.

• Identify the root cause of the CPU bottleneck through performance monitoring tools.

• Optimize the code by identifying and fixing inefficient algorithms or resource-intensive operations.

• Upgrade hardware by adding more powerful CPUs or increasing the number of cores.

• Implement load balancing techniques to distribute the workload across multiple CPUs or servers.

• Consider vertical scaling by upgr...read more

Load balancing distributes network traffic across multiple servers to ensure optimal resource use and prevent overload.

• Improves application availability by distributing requests evenly.

• Can be implemented using hardware (like load balancers) or software solutions (like Nginx).

• Example: A website with high traffic uses load balancing to direct users to different servers.

• Helps in scaling applications by adding more servers as demand increases.

• Types include round-robin, least conn...read more

Validating API responses in Postman involves checking status codes, response times, and data accuracy using tests.

• Check the status code: Use `pm.response.to.have.status(200)` to ensure the API call was successful.

• Validate response time: Use `pm.expect(pm.response.responseTime).to.be.below(200)` to ensure the response is quick.

• Verify response structure: Use `pm.expect(pm.response.json()).to.have.property('key')` to check for specific keys in the JSON response.

• Check data values...read more