Performance testing interview questions updated 090812
- 1. In the first round, the focus will be on load runner and perf testing concepts in it So, I think a guy with good load runner knowledge can do. Also, any person who have experience on different platforms like windows, Linux etc 1. What tools you have experienced? A:- RPT, Load Runner for 3 months and MS VSTS for 17 months. 2. What do you mean by Correlation? A:- FYI, correlation in load runner is same as extraction rule in MS VSTS. Correlation :- Each time a script is run, dynamic values such as session id's, cookie values change. So, to make the script running successfully for multiple times you will be adding correlation rules which takes the left and right boundaries of dynamic values and some parameter name. Dynamic values typically we found in the server response of the request passed. 3. You have some login unsuccessful case while browsing the site. While preparing the script, how do you make sure that script was failing with that error? A:- We keep a validation rule for the error we faced in the script 4. What is the function you use for correlation in Load Runner? A:- It is web_reg_save_param() function and it's arguments web_reg_save_param("parametername","Left Boundary","RoundBoundary") "RoundBoundary" is mandatory here while performing correlation 5. You have found one dynamic value in the script and you want to perform correlation in the script e.g.:- at the place where web_submit_url("www.google.com"). Where do you insert web_reg_save_param() function? A:- web_reg_save_param() function comes before the web_submit_url("www.google.com") 6. How many types of correlation are present in Load runner? A:- 1. Manual and 2. Automatic Correlation 7. Which is preferable Automatic or Manual Correlation A:- Always manual correlation is better because Automatic correlation is error prone some times i.e. it doesn't correlate properly. So, verifying and checking the automatic correlation is mandatory. 8. How do you monitor the counters? A:- In load runner :- Directly the servers counters values we can retrieve once we configure it In MS VSTS :- 2 ways 1. Directly adding the servers and counters we require. We can get the results once the load test is done
- 2. 2. Adding counters manually, by going to the server -> C:perflogsadminDatacollector.csv and setting several properties like sample interval, stop condition etc. We retrieved the values by using the customized tool we developed 9. How much you will be running the test? A:- Typically 30min and for endurance run it will be > 5 hours 10. What is ordinal in web_reg_save_param() (Load Runner)? A:- I said, i don't have any idea on it because I worked mostly on MS VSTS. 11. What do you mean by response times and what all you observe in the result sheet after the performance run? A:- Response times in brief is nothing but System Exit time – System Entry Time. We get all the client side metrics like pages/sec, avg response times of transactions, throughtput, tests/sec etc And Server side factors like server’s %cpu utilization, % available Mbytes, Nework bytes flowed etc Second Round :- Here concentration on technical topics and Aptitude questions 1. What projects you have handled and what is your role on your previous projects A:- I explained what all in detail what I have done etc. And showed interest to work on "Jmeter". 2. Once I gave, the entire explanation of my experience, Ravi asked me about the Test Plan A:- I said what all the perf test plan contains like scripts test mix, browser mix, network mix schedule, risks, roles and responsibilities etc 3. So, Test Plan is kind of a document ? A:- Yes, it is a document. But, in Jmeter it is the basic element. Here the terminology in Jmeter is different. Through, test plan, we create the ThreadGroups, samplers, Assertions etc. And we work on that. I said, I have some theoretical knowledge on Jmeter but no Hands on. As, I was tagged to Microsoft account, my most experience was restricted to VSTS. I like to explore my knowledge by working in Jmeter. Aptitude questions :- 1. You have 8 identical balls. All look very identical and all are of same weight except one. How do you take that out. You have a common balance before you A:- a) You first weigh 4 balls on one side and remaining 4 on another side.
- 3. Then, you select the 4 balls which has weight more and keep 2 on one side and remaining 2 on another side. Then, you will select the 2 balls which has more weight and ignore the remaining 2 balls. Now, repeat the same process for 2 balls, You can know which one is heavy. (There can be many other ways, but I think this is optimized way) 2. Water is flowing from the tap. You have 3L and 5L containers. you have to make a 4L container A:- First fill the water from the tap to 5L container. Fill 3L container from 5L container. Now 3L container is full and 5L container has 2L of water Clear the 3L container by dropping water outside Now, Fill the 3L container from 5L container (which has 2L of water presently) Now 3L container has 2L of water and 5L container is empty Fill again 5L container totally Fill 3L container fully from 5L container. Now, 3L container is full and 5L container has 4L of water. Also expecting the below from resource: 1. Who has basic knowledge on Performance testing concepts ( Preparing scripts, Correlation, Validation rules, Web Server Parameterization, Data Parameterization) 2. Adds up, if he works on more than one Platform like Window, Linux etc 3. Who has interest in working Java "Jmeter" 4. Who gives them the confidence, that he can handle the tasks whatever assigned to him confidently 5. And, If he expresses his performance testing experience like how he handled the projects previously etc 6. My role here involves both deployment to stress environment and starting the stress runs and reporting the issues if any and helping dev teams in preparing Jmeter Scripts(.Jmx). Deployment generally involves executing most of the linux commands. So, a person who has good knowledge on Linux can do. Recent interview questions: 1. What do you mean by Perf Testing, Stress and load testings? 2. Asked whether he has experience on Java Coding or not? 3. When did he used Memory Analyzer and Jmeter in his previous experience? 4. They asked him about his previous project(ITKO) and they also asked What is better Jmeter or Load Runner? Aptitude Question :- 5. There are 9 identical balls are of same weight except one. How will you differentiate that? 6. One combobox and one list box is given in a webpage. Based on the option selected in combobox, the items in the list box will change.How do you correlate in this case? It has some specific function to do this operation in load runner. 7. What do you mean by ordinal in web_reg_save_param(“parametername”, LB,RB,”ordinal”)
- 4. When will you apply and everything about that ordinal