Load Runner

Today, we are starting ‘Performance testing with LoadRunner’ tutorial series. This is the first tutorial in three-part HP LoadRunner training series. In first two tutorials we will introduce you to performance testing and in last tutorial we will share ‘Load Testing with LoadRunner video tutorials‘. See Also => List of all LoadRunner Video Tutorials. Why Performance testing? Performance testing has proved itself to be crucial for the success of a business. Not only does a poor performing site face financiallosses, it also could lead to legal repercussions at times.

No one wants to put up with a slow performing, unreliable site in cases of purchasing, online test taking, bill payment, etc. With the internet being so widely available, the alternates are immense. It is easier to lose clientele than gain them and performance is a key game changer. Therefore, performance testing is no longer a name sake checkpoint before going live. It is indeed a comprehensive and detailed stagethat would determine whether the performance of a site or an application meets the needs. Introduction The purpose of this test is to understand the performance of application under load, particularly users.

Types of Performance Testing

Load Testing Load testing is a type of performance test where the application is tested for its performance on normal and peak usage. Performance of an application is checked with respect to its response to the user request, its ability to respond consistently within accepted tolerance on different user loads. The key considerations are: 1. What is the max load the application is able to hold before the application starts behaving unexpectedly? 2. How much data the Database is able to handle before system slowness or the crash is observed? 3. Are there any network related issues to be addressed? Stress Testing Stress testing is the test to find the ways to break the system. The test also gives the idea for the maximum load the system can hold. Generally Stress testing has incremental approach where the load is increased gradually. The test is started with good load for which application has been already tested. Then

slowly more load is added to stress the system and the point when we start seeing servers not responding to the requests is considered as a break point. During this test all the functionality of the application are tested under heavy load and on back-end these functionality might be running complex queries, handling data, etc. The following questions are to be addressed:    

What is the max load a system can sustain before it breaks down? How is the system break down? Is the system able to recover once it’s crashed? In how many ways system can break and which are the weak node while handling the unexpected load?

Volume Testing Volume test is to verify the performance of the application is not affected by volume of data that is being handled by the application. Hence to execute Volume Test generally huge volume of data is entered into the database. This test can be incremental or steady test. In the incremental test volume of data is increased gradually. Generally with the application usage, the database size grows and it is necessary to test the application against heavy Database. A good example of this could be a website of a new school or college having small data to store initially but after 5-10 years the data stores in database of website is much more. The most common recommendation of this test is tuning of DB queries which access the Database for data. In some cases the response of DB queries is high for big database, so it needs to be rewritten in a different way or index, joints etc need to be included. Capacity Testing => Is the application capable of meeting business volume under both normal and peak load conditions? Capacity testing is generally done for future prospects. Capacity testing addresses the following: 1. Will the application able to support the future load? 2. Is the environment capable to stand for upcoming increased load? 3. What are the additional resources required to make environment capable enough? Capacity testing is used to determine how many users and/or transactions a given web application will support and still meet performance. During this testing resources such as processor capacity, network bandwidth, memory usage, disk capacity, etc. are considered and altered to meet the goal.

Online Banking is a perfect example of where capacity testing could play a major part. Reliability/Recovery Testing Reliability Testing or Recovery Testing – is to verify as to whether the application is able to return back to its normal state or not after a failure or abnormal behavior- and also how long does it take for it to do so(in other words, time estimation). An online trading site if experience a failure where the users are not able to buy/sell shares at a certain point of the day (peak hours) but are able to do so after an hour or two. In this case, we can say the application is reliable or recovered from the abnormal behavior. In addition to the above sub-forms of performance testing, there are some more fundamental ones that are prominent: Smoke Test: 

How is the new version of the application performing when compared to previous

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ones? Is any performance degradation observed in any area in the new version? What should be the next area where developers should focus to address performance issues in the new version of application?

See also => Smoke Testing in functional testing. Component Test:  

Whether the component is responsible for the performance issue? Whether the component is doing what is expected and component optimization has been done?

Endurance Test:   

Whether the application will able to perform well enough over the period of time. Any potential reasons that could slow the system down? Third party tool and/or vendor integration and any possibility that the interaction makes the application slower.

How does Functional Testing differ from Performance Testing?

Identification of components for testing In an ideal scenario, all components should be performance tested. However, due to time & other business constraints that may not be possible. Hence, the identification of components for testing happens to be one of the most important tasks in load testing. The following components must be included in performance testing: -----------#1. Functional, business critical features Components that have a Customer Service Level Agreement or those having complex business logic (and are critical for the business’s success) should be included. Example: Checkout and Payment for an E-commerce site like eBay. #2. Components that process high volumes of data Components, especially background jobs are to be included for sure.Example: Upload and download feature on a file sharing website. #3. Components which are commonly used A component that is frequently used by end-users, jobs scheduled multiple times in a day, etc. Example: Login and Logout. #4. Components interfacing with one or more application systems

In a system involving multiple applications that interact with one another, all the interface components must be deemed as critical for performance test. Example: E-commerce sites interface with online banking sites for payments, which is an external third party application. This should be definitely the part of Perf testing.

Tools for performance testing Sure, you could have a million computers set up with a million different credentials and all of them could login at once and monitor the performance. Apparently it’s not practical and even if we do, do that, we still need some sort of monitoring infrastructure. The best way this situation is handled is through – virtual user (VU).For all our tests the VU behave just the way a real user would. For the creation of as many VUs as you would require and to simulate real time conditions, performance testing tools are employed. Not only that, Perf testing also tests for the peak load usage, breakdown point, long term usage, etc To enable all with limited resources, fast and to obtain reliable results tools are often used for this process. There are a variety of tools available in the market- licensed, free wares and open sourced. Few of the such tools are:                      

HP LoadRunner, Jmeter, Silk Performer, NeoLoad, Web Load, Rational Performance Tester (RTP), VSTS, Loadstorm, Web Performance, LoadUI, Loadster, Load Impact, OpenSTA, QEngine, Cloud Test, Httperf, App Loader, Qtest, RTI, Apica LoadTest, Forecast, WAPT,

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Monitis, Keynote Test Perspective, Agile Load, etc.

See Also => List of top 15 Performance Testing tools The tool selection depends on budget, technology used, purpose of testing, nature of the applications, performance goals being validated, infrastructure, etc. HP Load Runner captures majority of market due to: 1. Versatility – can be used on windows as well as web based applications. It also works for many kinds of technologies. 2. Test Results – It provides in-depth insights that can be used for tuning the application. 3. Easy Integrations – works with diagnostics tool like HP Sitescope and HP Diagnostic. 4. Analysis utility provides a variety of features which help in deep analysis. 5. Robust Reports – LoadRunner has a good reporting engine and provides a variety of reporting formats. 6. Comes with an Enterprise package too. The only flip side is its license cost. It is a little bit on the expensive side – which is why other open source or affordably licensed tools that are specific to a technology, protocol and with limited analysis & reporting capabilities have emerged in the market. Still, the HP LoadRunner is a clear winner.

Future in Performance Testing Career Performance testing is easy to learn but need lots of dedication to master it. It’s like a mathematics subject where you have to build your concept. Once the concept is through, it can be applied to most of the tools irrespective of the scripting language being different, straight forward logic not being applicable, look and feel of the tool being different, etc. – the approach to Perf testing is almost always the same. I would highly recommend this hot and booming technology and to enhance your skill by learning this. Mastering PT could be just what you are looking for to move ahead in your software testing career.

Conclusion In this article we have covered most of the information required to build a base to move ahead and understand the Performance testing. In the next article we will apply these concepts and understand the key activities of Performance testing.

Next Tutorial => How to Performance Test an Application Load Runner is going to be our vehicle in the journey, but the destination we want to reach is to understand everything about performance testing. Stay tuned!

How to Performance Test an Application – LoadRunner Training Tutorial Part 2 Posted In | Automation Testing, LoadRunner Tutorials, Software Testing Tools | Last Updated: "February 12, 2015"

This is the 2nd tutorial in our Performance testing with LoadRunner training series. With this, we are learning

the exact performance test process so that we can easily get hold of the Load Testing with HP LoadRunner tutorials. Check out the first tutorials in this series here: Performance Testing Introduction. Performance Testing Goals: It is conducted to accomplish the following goals:  Verify Application’s readiness to go live.  Verify if the desired performance criteria are met  Compare performance characteristics/configurations of the application to what is standard  Identify Performance bottlenecks.  Facilitate Performance Tuning.

Key Activities in Performance Testing:

#1. Requirement Analysis/Gathering Performance team interacts with the client for identification and gathering of requirement – technical and business. This includes getting information on application’s architecture, technologies and database used, intended users, functionality, application usage, test requirement, hardware & software requirements etc.

#2. POC/Tool selection

Once the key functionality are identified, POC (proof of concept – which is a sort of demonstration of the real time activity but in a limited sense) is done with the available tools. The list of availableperformance test tools depends on cost of tool, protocol that application is using, the technologies used to build the application, the number of users we are simulating for the test, etc. During POC, scripts are created for the identified key functionality and executed with 10-15 virtual users.

#3. Performance Test Plan & Design Depending on the information collected in the preceding stages, test planning and designing is conducted. Test Planning involves information on how the performance test is going to take place – test environment the application, workload, hardware, etc. Test designing is mainly about the type of test to be conducted, metrics to be measured, Metadata, scripts, number of users and the execution plan. During this activity, a Performance Test Plan is created. This serves as an agreement before moving ahead and also as a road map for the entire activity. Once created this document is shared to the client to establish transparency on the type of the application, test objectives, prerequisites, deliverable, entry and exit criteria, acceptance criteria etc. Briefly, a performance test plan includes: a) Introduction (Objective and Scope) b) Application Overview c) Performance (Objectives & Goals) d) Test Approach (User Distribution, Test data requirements, Workload criteria, Entry & Exit criteria,

Deliverable, etc.) e) In-Scope and Out-of-Scope f) Test Environment (Configuration, Tool, Hardware, Server Monitoring, Database, test configuration, etc.) g) Reporting & Communication h) Test Metrics i) Role & Responsibilities j) Risk & Mitigation k) Configuration Management

#4. Performance Test Development  Use cases are created for the functionality identified in the test plan as the scope of PT.  These use cases are shared with the client for their approval. This is to make sure the script will be recorded with correct steps.  Once approved, script development starts with a recording of the steps in use cases with the performance test tool selected during the POC (Proof of Concepts) and enhanced by performing Correlation (for handling dynamic value), Parameterization (value substitution) and custom functions as per the situation or need. More on these techniques in our video tutorials.  The Scripts are then validated against different users.  Parallel to script creation, performance team also keeps working on setting up of the test environment (Software and hardware).  Performance team will also take care of Metadata (back-end) through scripts if this activity is not taken up by the client.

#5. Performance Test Modeling

Performance Load Model is created for the test execution. The main aim of this step is to validate whether the given Performance metrics (provided by clients) are achieved during the test or not. There are different approaches to create a Load model. “Little’s Law” is used in most cases.

#6. Test Execution The scenario is designed according to the Load Model in Controller or Performance Center but the initial tests are not executed with maximum users that are in the Load model. Test execution is done incrementally. For example: If the maximum number of users are 100, the scenarios is first run with 10, 25, 50 users and so on, eventually moving on to 100 users. ------------

#7. Test Results Analysis Test results are the most important deliverable for the performance tester. This is where we can prove the ROI (Return on Investment) and productivity that a performance testing effort can provide.

Some of the best practices that help the result analysis process: a) A unique and meaningful name to every test result – this helps in understanding the purpose of the test b) Include the following information in the test result summary:  Reason for the failure/s  Change in the performance of the application compared to the previous test run  Changes made in the test from the point of application build or test environment.  It’s a good practice to make a result summary after each test run so that analysis results are not compiled every time test results are referred.  PT generally requires many test runs to reach at the correct conclusion.  It is good to have the following points in result summary:  Purpose of test  Number of virtual users  Scenario summary

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Duration of test Throughput Graphs Graphs comparison Response Time Error occurred Recommendations

There might be recommendations like configuration changes for the next test. Server logs also help in identifying the root cause of the problem (like bottlenecks) – Deep Diagnostic tools are used for this purpose. In the final report, all the test summaries are consolidated.

#8. Report Test results should be simplified so the conclusion is clearer and should not need any derivation. Development Team needs more information on analysis, comparison of results, and details of how the results were obtained. Test report is considered to be good if it is brief, descriptive and to the point. The following guidelines will smooth this step out:  Use appropriate heading and summary  Report should be presentable so that it can be used in the management meetings.  Provide supporting data to support the results.  Give meaningful names to the table headers.  Share the status report periodically, even with the clients

 Report the issues with as much information and evidence as possible in order to avoid unnecessary correspondence The final report to be shared with the client has the following information:       

Execution Summary System Under test Testing Strategy Summary of test Results Strategy Problem Identified Recommendations

Along with the final report, all the deliverable as per test plan should be shared with the client.

Conclusion We hope this article has given a process oriented, conceptual and detailed information on how performance testing is carried out from beginning to end.

In the past tutorials we have seen the basics of Performance testing and LoadRunner video tutorials. This article is going to focus on the most important commonly asked

LoadRunner interview questions and answers that will help you be successful in performance tester’s interview using LoadRunner. LoadRunner is one of the best licensed Performance testing tools in the market. It is best suited for most upcoming technologies because of the wide range of supported protocols. A few basic pointers before we begin: #1) LoadRunner interview questions can be categorized into 3 main types – Scripting, Execution and Analysis. It is important for beginners to focus more on the scripting part. #2) Http/html is mostly used protocol, for a start try to perfect this protocol. #3) Be sure to know the exact version of LoadRunner that you worked on. In case of work experience with a previous version, try to keep yourself updated with the features that are part of the newer/current versions. #4) Performance Testing interviews are more practical than they used to be. Scenario oriented questions are common rather than straight forward ones. Some companies, even make scripting tests a part of the interview process. So, be prepared for the same. #5) Even in scripting, it is preferred that you be able to customize code, instead of just record and replay. #6) Expect questions on – think time, transactions, comments, recording options, run time settings, etc. – these are to test your knowledge of scripting best practices.

The following are some of the performance testing interviewquestions that will need some experience to answer. Try to keep these questions in mind while working on your performance test projects, so the interview preparation activity becomes a continuous process. 1. What are the different scripting issues you faced so far? 2. What are the performance bottlenecks that you found in projects you were working? What are the recommendations made to overcome those issues? 3. Have you applied Little’s law in your project? If so, how? 4. What is your approach for analysis? 5. What do you monitor while execution? 6. How to extract server data for test execution and how to analyze that? 7. How to identify performance bottlenecks? Key question areas are:  Challenges that you face during scripting  Correlation function

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Error handling Different recording modes for Web HTTP/HTML protocol. Scenario creation Challenges during execution Analysis

See also => Performance Testing with LoadRunner Below we provided few common LoadRunner interview questions and answers to them. However, please note that the best results can be achieved by providing answers based on your exposure, expertise and interpretation of the concepts. Learning just the answers to questions is not always optimum. Practice, Learn and Expert – this should be your approach for performance testing interview preparation.

LoadRunner Interview Questions and Best Answers Q #1. What is the difference between Performance testing and Performance engineering? Ans => In Performance testing, testing cycle includes requirement gathering, scripting, execution, result sharing and report generation. Performance Engineering is a step ahead of Performance testing where after execution; results are analyzed with the aim to find the performance bottlenecks and the solution is provided to resolve the identified issues. Q #2. Explain Performance Testing Life Cycle. Ans => Step 1: System Analysis (Identification of critical transaction) Virtual User Generator Step 2: Creating Virtual User Scripts (Recording) Step 3: Defining Users Behavior (Runtime setting) LoadRunner Controller Step 4: Creating Load Test Scenarios Step 5: Running the Load Test Scenarios and Monitoring the Performance LoadRunner Analysis Step 6: Analyzing the Results Refer Performance Testing Tutorial #2 for more details. Q #3. What is Performance testing? Ans => Performance testing is done to evaluate application`s performance under load and stress conditions. It is generally measured in terms of response time of user’s action on application. Q #4. What is Load testing? Ans => Load testing is to determine if an application can work well with the heavy usage resulting from a large number of users using it simultaneously. Load is increased to to simulates the peak load that the servers are going to take during maximum usage periods. Q #5. What are the different components of LoadRunner? Ans => The major components of LoadRunner are: VUGen- Records Vuser scripts that emulate the actions of real users. Controller – Administrative center for creating, maintaining and executing load test scenarios. Assigns scenarios to Vusers and load generators, starts and stops loading tests.

Load Generator – An agent through which we can generate load Analysis – Provides graphs and reports that summarize the system performance Q #6. What is the Rendezvous point? Ans => Rendezvous point helps in emulating heavy user load (request) on the server. This instructs Vusers to act simultaneously. When the vuser reaches the Rendezvous point, it waits for all Vusers with Rendezvous point. Once designated numbers of Vusers reaches it, the Vusers are released. Function lr_rendezvous is used to create the Rendezvous point. This can be inserted by: 1. Rendezvous button on the floating Recording toolbar while recording. 2. After recording Rendezvous point is inserted through Insert> Rendezvous. Q #7. What are the different sections of the script? In what sequence does these section runs? Ans => LoadRunner script has three sections vuser_init, Action and vuser_end. vuser_init has requests/actions to login to the application/server. Action has actual code to test the functionality of the application. This can be played many times in iterations. Vuser_end has requests/actions to login out the application/server. The sequence in which these sections get executed is vuser_init is at the very beginning and vuser_end at the very end. Action is executed in between the two. Q #8. How do you identify which protocol to use for any application? Ans => Previously Performance tester had to depend much on the development team to know about the protocol that application is using to interact with the server. Sometimes, it also used to be speculative. However, LoadRunner provides a great help in form of Protocol Advisor from version 9.5 onwards. Protocol advisor detects the protocols that application uses and suggest us the possible protocols in which script can be created to simulate the real user. Q #9. What is correlation? Explain the difference between automatic correlation and manual correlation? Ans => Correlation is used to handle the dynamic values in a script. The dynamic value could change for each user action (value changes when action is replayed by the same user) or for different users (value changes when action is replayed with different user). In both the cases correlation takes care of these values and prevents them from failing during execution. Manual Correlation involves identifying the dynamic value, finding the first occurrence of dynamic value, identifying the unique boundaries of capturing the dynamic value, writing correlation function web_reg_save_param before the request having the first occurrence of dynamic value in its response. Automated correlation works on predefined correlation rules. The script is played back and scanned for auto correlation on failing. Vugen identifies the place wherever the correlation rules work and correlate the value on approval. Refer this tutorial for more details. Q #10. How to identify what to correlate and what to parameterize? Ans => Any value in the script that changes on each iteration or with different user

while replaying needs correlation. Any user input while recording should be parametrized. Q #11. What is parameterization & why is parameterization necessary in the script? Ans => Replacing hard coded values within the script with a parameter is called Parameterization. This helps a single virtual user (vuser) to use different data on each run. This simulates real life usage of application as it avoids server from caching results. Refer this tutorial for more details. Q #12. How you identify Performance test use cases of any application? Ans => Test cases/Uses cases for Performance test are almost same as any manual/functional testing test cases where each and every step performed by the user is written. The only difference is that all manual test cases can’t be Performance testing use cases as there are few criteria for the selection as: I. The user activity should be related to critical and most important functionality of the application. II. The user activity should be having good amount of database activity such as search, delete or insert. III. The user activity should be having good user volume. The functionality having less user activity is generally omitted from Performance testing point of view. e.g admin account activity. Any of the manual test cases that fulfill the above criteria can be used as performance testing use case/test case. If manual test cases are not written step by step , Performance team should create dedicated documents for them. Q #13. While scripting you created correlation rules for automatic correlation. If you want to share the correlation rules with your team member working on the same application so that he/she can use the same on his workstation, how will you do that? Ans => Correlation rules can be exported through .cor file and the same file can be imported through VuGen. -----------Q #14. What are different types of vuser logs which can be used while scripting and execution? What is the difference between these logs? When you disable logging? Ans => There are two types of Vuser logs available –Standard log and Extended log. Logs are key for debugging the script. Once a script is up and running, logging is enabled for errors only. Standard log creates a log of functions and messages sent to the server during script execution whereas Extended log contains additional of warnings and other messages. Logging is used during debugging and disabled while execution. Logging can be enabled for errors in that case. Q #15. What is Modular approach of scripting? Ans => In Modular approach, a function is created for each request (e.g. login, logout, save, delete, etc.) and these functions are called wherever required. This approach gives more freedom to reuse the request and saves time. With this approach it is recommended to work with web custom request.

Q #16. What are the different types goals in Goal-Oriented Scenario? Ans => LoadRunner has five different types of goals in Goal-Oriented Scenario. These are:  The number of concurrent Vusers  The number of hits per second  The number of transactions per second  The number of pages per minute  The transaction response time Q #17. How is each step validated in the script? Ans => Each step in the script is validated with the content on the returned page. A content check verifies whether specific content is present on the web page or not. There are two types of content check which can be used in LoadRunner: Text Check- This checks for a text/string on the web page Image Check- This checks for an image on a web page. Q #18. How is VuGen script modified after recording? Ans => Once the script is recorded, it can be modified with the following process: Transaction Parameterization Correlation Variable declarations Rendezvous Point Validations/Check point Q #19. What is Ramp up and Ramp Down? Ans => Ramp up- Rate at which virtual users add to the load test Ramp Down- Rate at which virtual users exit from the load test. Q #20. What is the advantage of running the Vuser as thread? Ans => Running vusers as thread helps generate more virtual users from any machine due to small memory print of the vuser running as thread. Q #21. What is wasted time in VuGen Replay log? Ans => Waste time is never performed by any browser user and just the time spent on the activities which support the test analysis. These activities are related to logging, keeping record and custom analysis. Q #22. How do you enable text and image checks in VuGen? Ans => This can be done by using functions web_find (for text check) and web_image_check (for image check) and enabling image and text check from run time setting. Run Time Setting–>Preference–>Enable the Image and text check box. Q #23. What is the difference between web_reg_find and web_find? Ans => web_reg_find function is processed before the request sent and is placed before the request in the VuGen script whereas web_find function is processed after the response of the request come and is placed after the request in VuGen script. Q #24. What are the challenges that you will face to script the step “Select All” and then “Delete” for any mail account? Ans => In this case the post for “Select All” and “Delete” will change every time depending on the number mails available. For this the recorded request for the two should be replaced with custom request and string building is required to build the post.

(Note- This question needs practical knowledge. So please this practically and formulate your answer). Q #25. What is difference between pacing and think time? Ans => Pacing is wait time between the action iterations whereas think time is wait time between the transactions. Q #26. What are the number of graphs you can monitor using Controller at a time? What is the max of them? Ans => One, two, four and eight graphs can be seen at a time. The maximum number of graphs can be monitored in at a time is 8. Q #27. You have an application which shows the exam results of the student. Corresponding to name of each student its mentioned whether he passed or failed the exam with the label of “Pass” and “Fail”. How will you identify the number of passed and failed student in VuGen script? Ans => For this text check is used for the web page for the text “Pass and “Fail”. Through the function web_reg_find, we can capture the number of texts found on the web page with the help of “SaveCount”. SaveCount stored the number of matches found. For example1 web_reg_find("Text=Pass", 2 "SaveCount=Pass_Student", 3 LAST); 4 web_reg_find("Text=Fail", 5 "SaveCount=Fail_Student", 6 LAST); Q #28. During the load test what is the optimum setting for Logs? Ans => For the load test log level is set to minimal. This can be achieved with setting the log level to the standard log and selecting the radio button “Send message only when an error occurs”. Q #29. How will you handle the situation in scripting where for your mailbox you have to select any one mail randomly to read? Ans => For this we will record the script for reading the first mail. Try to find what is being posted in the request to read the first mail such as mail ids or row no. From the post where a list of mails is reflecting, we will try to capture all the email ids row no with correlation function and keeping Ordinal as All i.e. ORD=All . Replace the requested email id in the read post with any of the randomly selected email id from the list of captured email ids. Refer this Scripting Tutorial. Q #30. What is the Think Time? What is the Threshold level for think time and how can be this changed? Ans => Think time is the wait time inserted intentionally between the actions in the script to emulate real user`s wait time while performing activity on the application. The Threshold level for Think time in the level below which recorded think time will be ignored. This can be changed from Recorded options->Script->Generate think time greater than threshold. Q #31. How is Automated Correlation configured? Ans => Any setting related to Automated Correlation can be done byGeneral Options>Correlation. Correlation rules are set fromRecording options->Correlations.

Q #32. How you decide the number of load generator machine required to run a test? Ans => Number of load generator required totally depends on the protocol used to create the script and configuration of the load generator machine. Each protocol has different memory print and this decides how many virtual users can be generated from the give configuration of the machine (load generator). Q #33. What are the capabilities exactly you look for while selecting the performance testing tool? Ans => Performance testing tool should capable of: Testing an application built using multiple technologies and hardware platforms.  Determine the suitability of a server for testing the application  Testing an application with load of tens, thousand and even thousands virtual users. Q #34. How concurrent users are differing from simultaneous users? Ans => All simultaneous users are concurrent users but vice versa is not true. All the vusers in the running scenario are Concurrent users as they are using the same application at the same time but may be or may not be doing the same tasks. Simultaneous users perform the same task at the same time. Concurrent users are made Simultaneous users through rendezvous points. Rendezvous points instruct the system to wait till a certain number of vusers arrive so that they all can do a particular task simultaneously. Q #35. How do you identify which values need to be correlated in the script? Give an example. Ans => This can be done in ways: a) Record the two scripts with similar steps and compare them using WDiff utility. (See tutorial Correlation). b) Replay the recorded script and scan for correlation. This gives a list of values that can be correlated. Session Id is a good example of this. When two scripts are recorded and compared using WDiff utility. Session ids in the two scripts should be different and WDiff highlight these values. Q #36. How does caching affect performance testing results? Ans => When data is cached in server`s memory, the server need not fetch the result and no server activity triggered. Test result does not reflect the same performance of real user using the application with different data. Q #37. How will you stop the execution of script on error? Ans => This can be achieved through lr_abort function. The function instructs the vuser to stop executing Action section and end the execution by executing the vuser_end section. This function is helpful in handling a specific error. This can also be used to handle a situation rather than error where execution is not possible. The function assigned “Stopped” status to the vuser which stopped due to lr_abort function. In RunTime setting, “Continue on error” should be unchecked.

LoadRunner Interview Questions -1 1) What is Performance Testing? The process of testing to determine the performance of software product. 2) What is Load Testing? A type of performance testing conducted to evaluate the behavior of a component or system with increasing load, e.g. numbers of parallel users and/or numbers of transactions, to determine what load can be handled by the component or system. 3) What is Stress Testing? A type of performance testing conducted to evaluate a system or component at or beyond the limits of its anticipated or specified work loads, or with reduced availability of resources such as access to memory or servers. 4) What is Spike Testing? Verify the System’s performance under sudden increments and decrements. 5) What is Data Volume Testing? Testing where the system is subjected to large volumes of data. 6) What is Endurance Testing? Verifying the System’s performance under continues load in terms of users and transactions. 7) What is LoadRunner? It is a Performance Test Tool from HP. It supports all aspects of Performance Testing like Load, Stress, Endurance, spike and Data volume testing. 8) What are the tools available in the industry for Load Testing?

LoadRunner from HP RPT (Rational Performance Tester) from IBM Silk Performer from Micro Focus JMeter (Open source Tool) Etc…

9) What is latest version of LoadRunner? LoadRunner 11.5 10) What is the scripting language that used in LoadRunner? VUser script (It is C like language) 11) What are the 4 important components in LoadRunner? Virtual User Generator (VUGEN) Controller Load Generator Analysis 12) How do you identify the performance bottlenecks? Performance Bottlenecks can be detected by using monitors. These monitors might be application server monitors, web server monitors, database server monitors and network monitors. They help in finding out the troubled area in our scenario which causes increased response time. The measurements made are usually performance response time, throughput, hits/sec, network delay graphs, etc. 13) If web server, database and Network are all fine where could be the problem? The problem could be in the system itself or in the application server or in the code written for the application. 14) How did you find web server related issues? Using Web resource monitors we can find the performance of web servers. Using these monitors we can analyze throughput on the web server, number of hits per second that occurred during scenario, the number of http responses per second, the number of downloaded pages per second. 15) How did you find database related issues? By running “Database” monitor and help of “Data Resource Graph” we can find database related issues. E.g. You can specify the resource you want to measure on before running the controller and than you can see database related issues 16) Explain all the web recording options?

17) What is the difference between Overlay graph and Correlate graph? Overlay Graph: It overlay the content of two graphs that shares a common x-axis. Left Y-axis on the merged graph show’s the current graph’s value & Right Y-axis show the value of Y-axis of the graph that was merged. Correlate Graph: Plot the Y-axis of two graphs against each other. The active graph’s Y-axis becomes Xaxis of merged graph. Y-axis of the graph that was merged becomes merged graph’s Yaxis. 18) How did you plan the Load? What are the Criteria? Load test is planned to decide the number of users, what kind of machines we are going to use and from where they are run. It is based on 2 important documents, Task Distribution Diagram and Transaction profile. Task Distribution Diagram gives us the information on number of users for a particular transaction and the time of the load. The peak usage and off-usage are decided from this Diagram. Transaction profile gives us the information about the transactions name and their priority levels with regard to the scenario we are deciding. 19) What does vuser_init action contain? Vuser_init action contains procedures to login to a server. 20) What does vuser_end action contain? Vuser_end section contains log off procedures. 21) What is Performance Test Tool? A tool to support performance testing that usually has two main Facilities: load generation and test transaction measurement. Load generation can simulate either multiple users or high volumes of input data. During execution, response time measurements are taken from selected transactions and these are logged. Performance testing tools normally provide reports based on test logs and graphs of load against response times. 22) What are the phases in LoadRunner Test Process? I) Planning the Test II) Creating VUser Scripts III) Creating the Scenario IV) Running the Scenario V) Monitoring the Scenario

VI) Analyzing Test Result 23) How LoadRunner interact with Software Application? LoadRunner interacts with Software Application based on Protocols. 24) What is Protocol? A set of rules that enable Computer devices to connect and transmit data to one another. Protocols determine how data are transmitted between computing devices and over networks. 25) What are the important Protocol Bundles that LoadRunner supports? LoadRunner Supporting Protocol Bundles .NET Record/Replay Database DCOM Network Oracle E-Business Remote Access Rich Internet Applications SAP SOA Templates Web and Multimedia Wireless GUI Java Record/Replay Remote Desktop

Web 2.0

LoadRunner Interview Questions and Answers -2 1) What is the extension of LoadRunner scenario file? Extension of LoadRunner scenario file is .lrs 2) How many areas we can do the correlation? Areas of correlation are: 1) ItemData 2) TimeStamp 3) Links 4) Check Boxes 5) List Buttons 6) Radio Buttons 3) Tell something about LoadRunner? 1) LoadRunner is the industry standard automated performance and load testing tool. 2) HP acquired LoadRunner as part of its acquisition of Mercury Interactive. 3) Using LoadRunner one can emulated hundreds and thousand of virtual users for performance and load testing. 4) LoadRunner supports wide range of industry standard applications for load testing. 4) What are the features of HP LoadRunner? The key features of HP LoadRunner are as follows: 1. TruClient technology that simplifies and accelerates scripting for complex Rich Internet applications.

2. Enterprise load generation that applies measurable and repeatable loads while monitoring systems and end-user transactions to identify issues. 3. Powerful analysis and reporting capabilities that help isolate performance bottlenecks quickly and easily. 4.Integrated diagnostics help pinpoint the root causes of application-level issues down to the code level. 5) What is a virtual user or VUser in LoadRunner? Virtual user or Vuser emulates the real user steps. The real user steps are recorded a test script. During the recording time user steps (like posting the requests or accessing the pages) are recorded as test script. When the test script is played back the script is going to perform the user actions. The real user emulation by playing back the script is called virtual user or vuser. The vusers are created as a process or a thread in LoadRunner for multiple users. 6) What are the LoadRunner components? LoadRunner has majorily 4 components 1. LoadRunner VuGen - Virtual user generator - used for scripting purpose. 2. LoadRunner Controller - used for load test execution and monitoring purpose. 3. LoadRunner Load Generator - used for generating the load of multiple virtual users. 4. LoadRunner Analysis - used for analysis and reporting purpose. 7) What is a transaction in LoadRunner? Transaction is defined as response time of one or more than one user steps. Transaction in LoadRunner is used for measuring the response time of user steps. If one has to measure the response time one or more than one page, the measure statements will be inserted at the appropriate pages. lr_measure_start("trans1") Step 1 Step 2 lr_measure_stop("trans1") lr_measure_start("trans2)

Step 3 lr_measure_stop("trans2) Step 4 trans1 and trans2 are transaction names, which will have the response times to measure periodically and those response times will be displayed from the graphs in controller during the load test execution and those transaction response times can be analyzed from LoadRunner analysis after load test execution. 8) What is think time in LoadRunner? Think time is nothing but the user delay between two subsequent requests. Assume that a user opened page1 and he is filling the data on page1. During filling the page the user has spent 10 sec, and he has submitted the page1, then page2 is loaded. In this case the user wait time between pag1 and page2 10 sec is called think time. 9) What is tuning in LoadRunner? How to use this tuning option in any project?Any one pls explain me in detail.? We are having different tunings like DB Tuning, Network Tuning, and Server Tuning and so on. 10) What is VUGen? The VUGen stands for Virtual User Generator. VuGen is used to generate vuser script (here we record a business operation performed by a single user). 11) What is the analyzer in LoadRunner? This gives you the results of the load runner test. These results can be viewed in graphs and reports. 12) Do we see much difference in load testing for web applications versus traditional software? Yes. From own experience, in traditional applications, the developers know more about how it all works, if it’s in house then developers are easy to access and know the environment. With Web and CMS, there is so much the developers don’t know about, this is especially true when they integrate out of the box solutions. So many software developers now are using solutions they buy from someone else and they are slow to turn

around bugs, functional or non-functional. Obviously this depends on a lot again, traditional applications can also fall into these traps, but it’s more common with Web. 13) What are some of the most common web app bottlenecks that you find and/or fix? Some of the most common web app bottlenecks that you find and/or fix: Misconfigured server, poor performing stored procedure, or the application. Less down to infrastructure as most places we have been they spend a lot of money in this area. 14) Have you ever measured application performance reengineering impact by operations cost reduction? Yes. We can test a work-flow application, and the speed of this application had an impact on both the productivity of a large portion of their workforce, and the performance of their helpdesk staff, which had a direct effect on their reputation. 15) What do you think is the most important aspect of load testing? Most important aspect of load testing: As mentioned getting the scenario right and answering the business question. No point telling them , “it breaks at 1000 users, when they have 100 people working there and they were concerned only with network latency". (Simplistic example as we know). 16) What kind of applications LR tests? LR tests Client / Server & Web based applications. 17) What is correlation? Correlation is used to obtain data which are unique for each run of the script and which are generated by nested queries. Correlation provides the value to avoid errors arising out of duplicate values and also optimizing the code (to avoid nested queries). Automatic correlation is where we set some rules for correlation. It can be application server specific. Here values are replaced by data which are created by these rules. In manual correlation, the value we want to correlate is scanned and create correlation is used to correlate. 19) How do you find out where correlation is required?

In two ways we can find out where correlation is required. First we can scan for correlations, and see the list of values which can be correlated. From this we can pick a value to be correlated. Secondly, we can record two scripts and compare them. We can look up the difference file to see for the values which needed to be correlated. 20) Why do you create parameters? Parameters are like script variables. They are used to vary input to the server and to emulate real users. Different sets of data are sent to the server each time the script is run. Better simulate the usage model for more accurate testing from the Controller; one script can emulate many different users on the system. 21) What is the controller in LoadRunner? The more important and critical component of LoadRunner is the Controller. LoadRunner uses the Controller to emulate the real time users. Here is where we configure our scenario settings like Scripts need to be executed, No of Vusers, Load Generators, Run-time settings, Load test duration etc.. 22) What is the use of Scheduler? We can use the LoadRunner Scheduler to set up a scenario to run automatically. 23) What are the reasons why parameterization is necessary when load testing the Web server and the database server? Parameterization is useful for performance scripts for varous reasosn: 1. We can use different data in scripts dynamically. 2. When URLs of AUT are parameterized, it becomes easy for the script to point to different application environments, i.e. Dev, QA or Prod depending upon the requirements. 3. Parameterizing helps in emulation real scenario as it avoids caching effect, if we send same data again and again while running scripts in iteration, then the data could be used from cache or from the temporary table from the database. Now if we send different data in each iteration the real performnace transaction timers can be measured. 24) What is the difference between hits/second and requests/second?

Hits per second means the number of hits the vserver receives in one second from the vuser and the request per second is the no. of request the vuser will request from the server. 25) What is the advantage of using LoadRunner? Advantages are: 1. With help of vusers reduces the human users 2. Reduces the reqirement of the systems 3. Helps in the better usage of time and money 4. Effective utilization of automation 5. Everything done from a single point.

LoadRunner Interview Questions and Answers -3 1) How do you identify the performance bottlenecks? Performance Bottlenecks can be detected by using monitors. These monitors might be application server monitors, web server monitors, database server monitors and network monitors. They help in finding out the troubled area in our scenario which causes increased response time. The measurements made are usually performance response time, throughput, hits/sec, network delay graphs, etc. 2) What are the tools available in the industry for Load Testing? HP-LoadRunner IBM - RPT (Rational Performance Tester) Micro Focus - Silk Performer JMeter (Open source Tool) QA WebLoad (RadView) Etc... 3) What are the considerable factors in Performance Result Analysis using LoadRunner? Performance Bench Marks Local System Configuration

Network communicators Server response 4) How to identify the memory leakage using Loadrunner? In Load runner, every application has a processor running in the system. The processor needs to be identified. Using the performance tab we can check the memory consumption of the processor. Continuous tracking needs to be done while load testing. However, if the memory keeps increasing even on stopping the test, a memory may have occurred. Also, if the memory is not released on stopping the test, a memory may have occurred. 5) How do we debug a LoadRunner script? Debugging a LoadRunner script: VuGen contains two options to help debug Vuser scripts-the Run Step by Step command and breakpoints. The Debug settings in the Options dialog box allow us to determine the extent of the trace to be performed during scenario execution. The debug information is written to the Output window. We can manually set the message class within your script using the lr_set_debug_message function. This is useful if we want to receive debug information about a small section of the script only. 6) What are the performance tester roles and responsibilities using loadrunner? There won't be load runner roles and responsibilities. It is the roles of performance engineer and there won't be difference between the roles what ever tool you use for performance testing. 7) When do you do load and performance Testing? We perform load testing once we are done with interface (GUI) testing. Modern system architectures are large and complex. Whereas single user testing primarily on functionality and user interface of a system component, application testing focuses on performance and reliability of an entire system. For example, a typical application-testing scenario might depict 1000 users logging in simultaneously to a system. This gives rise to issues such as what is the response time of the system, does it crash, will it go with different software applications and platforms, can it hold so many hundreds and thousands of users, etc. This is when we set do load and performance testing. 8) Do you feel like performance testing is an accepted critical part of the development life cycle? It is getting that way yes, with more and more crashes getting exposure on the news here and with it happening more and more it has become a critical part of testing. 10) What are the key KPIs you track for performance testing and tuning? The key KPIs that we track for performance testing are transaction response time, memory usage, disk space, and CPU time. Tuning: Network delay and stored procedure times.

11) What is Throughput? Basically, “Throughput” is the amount of transactions produced over time during a test. It’s also expressed as the amount of capacity that a website or application can handle. Also before starting a performance test it is common to have a throughput goal that the application needs to be able to handle a specific number of requests per hour. 12) What is peak load testing? Peak load is the maximum amount of concurrent users that are on a website within a certain time period. For example, if you own a retail website, your peak load during any given week is most likely to be on the weekend. It would also follow that the Thanksgiving and Christmas holiday season is your busiest overall. 13) What is the focus of Performance testing? The focus of Performance testing is checking a software program’s • Speed – Determines whether the application responds quickly. • Scalability – Determines maximum user load the software application can handle. • Stability – Determines if the application is stable under varying loads. 14) What is the goal of performance testing? The goal of performance testing is not to find bugs but to eliminate performance bottlenecks. 15) Can anybody give me example for load testing? Load testing will simulate a real time user load on the application and testing. For example: Searching functionality in a website. If a website needs to accommodate a certain number of simultaneous users, for instance 1000 people using the search engine at the same time, then the site should be tested for that load before putting the website into production. Each of these 1000 visitors can access this website with different browsers, different versions of the same browser, different machines in different platforms. Their connections can range from highbandwidth data lines to dial-up. Load testing is designed to verify that the website can handle the expected load. 16) What is Endurance Testing? Endurance Testing means testing is done with expected user load sustained over longer period of time with normal ramp up and ramp down time and to identify Memory Leaks. 17) What is Volume Testing? Volume testing is a typical load testing except that a large volume of data is populated on the database to study its impact on the application response time and database overall health ; Behavior at various DB volumes. E.g. Checks for Accumulated counts, logs, and data files. 18) What is Scalability Testing?

Scalability testing is a process of evaluating the systems behaviour when the number of simultaneous users is increasing, and the hardware and software resources are fixed. This testing will be conducted for comparing the response times and system resource utilization of AUT when the number of users are increased. 19) What are the results reported after capacity Testing? Results Reported after capacity Testing are: • The hardware resource related bottlenecks will be reported. • Recommendation on new hardware. • Up-gradation of existing hardware. • Change in the existing application deployment architecture to support the future growth. • Introducing new servers in the application deployment architecture. 20) What are the results reported after Stress Testing? Results Reported after Stress Testing are: 1. The maximum number of users supported by AUT. 2. Let us assume that, the system resources are utilized beyond the expected limits. After the stress test, when the normal amount of users are running, the status of the application in terms of the resources utilization will be reported. 3. Assume that there are many errors are coming when the stress testing is been conducted. After the stress test, when the normal amount of users are running the status of the application in terms of the errors will be reported. 21) What are the disadvantages of using commercial performance / load testing tools? Disadvantages of using commercial performance/load testing: We need to understand the need for any commercial tool with respect to the kind of technologies we use in your organisation. A tool that do not support the technologies is waste of time and money. If it can fit into our requirements, there is a considerable ROI. 22) How do you test an application if it is going production for the first time? For testing the application, you need to have the basic scenarios done first. Second step will be to do the End to End testing with E2E scenarios. Third test will be to do the rigorous testing. Final step will be to do the load testing. 23) Why should we automate the performance testing? Its a discipline that leverages products, people and processes to reduce the risk of application, upgrade or patch deployment. It is about applying production work loads to pre-deployment systems while simultaneously measuring system performance and enduser experience. 24) What are the results reported after the Endurance/Longevity/Soak Testing? Results Reported after the Endurance / Longevity / Soak Testing Test:

When the endurance test is conducted on a multi tier web based enterprise level applications the following kind of results will be reported. • Memory leaks on the application servers • JVM Heap size utilization on the application servers • Connection leaks on the database server • Cursor leaks on the data base servers • Response time (consistency or degradation) comparison for start of the load test to end of the load test • Systems Resource (Memory, CPU, Network and Disk usage etc) comparison for beginning of the load test to end of the load test • Application errors occurrence over the period of time. 25) What are all the things will be considered while doing performance testing? Does the application respond quickly enough for the intended users? Will the application handle the expected user load and beyond? Will the application handle the number of transactions required by the business? Is the application stable under expected and unexpected user loads? Are we sure that users will have a positive experience on go-live day? 26) What are the results reported after the load Testing? Results Reported after the load Test: • The system will be validated to ensure whether the service level agreements or performance objectives are met. • Average, max, min and standard deviation of response times for each scenario will be measure and reported. • Resource utilization of each of the systems which are part of AUT will be monitored and reported. • If there is any application break point below the peak load condition, it need to be identified and reported. 27) What are the results reported after Spike Testing? Results Reported after Spike Testing: • The systems resources are utilization comparison for, with and without spikes. • The response times comparison for, with and without spikes. • Observation on errors for, with and without spikes. 28) What is remote command launcher? The remote command launcher enables the controller to start applications on the host machine. 29) How to determine the Stress Point? Determining the Stress Point: • Transaction response times are exponentially increased • The application started throwing the errors for many users • The system stopped responding • At least one of the server in AUT architecture got crashed • The system resource utilization went beyond the acceptable limits.

30) What are the results reported after Scalability Testing? Results Reported after Scalability Testing: • The comparison charts of different number of users and their response times. • The comparison charts of system resource utilization for different amount of users. • Scalability issues when the number of users are incremented. • Identification of scalable point of the application.