Most Commonly asked LoadRunner and Performance testing Interview Questions.
General Guidelines: Most of the interviewers like the answers with example from your projects. For example, if they ask “What is Parameterization”.Instead of giving the formal definition, it will be better, if you take an example from your last project and explain clearly where and how you have used this concept.
1.Problem Statement: Mark the transaction as pass if it is less than certain time; Let’s say 3 secs?
For accomplishing this problem statement, we have to use LR function “lr_get_transaction_duration”. This function captures the response time of that particular request and stores the value in a double.
Code snippet for above
double Res_Time;
lr_start_transaction(“LAUNCH”);
web_url(“index.htm”,
“URL=http://127.0.0.1:1080/WebTours/index.htm“,
“TargetFrame=”,
“Resource=0“,
“RecContentType=text/html“,
“Referer=”,
“Snapshot=t1.inf“,
“Mode=HTML“,
LAST);
Res_Time = lr_get_transaction_duration(“LAUNCH”);
if (Res_Time < 2)
{
lr_end_transaction(“LAUNCH”, LR_AUTO);
}
else
{
lr_end_transaction(“LAUNCH”, LR_FAIL);
}
2.Do we need to enable any setting for Text checkpoint and Image checkpoint to work?
Yes… One needs to enable “Image and Text Checkpoints” in Run-time Settings –> Internet Protocol –> Preferences. By Default this settings is disabled.
3.What is the difference between Correlation and Parameterization?
| Correlation | Parameterization |
| Used for handling the dynamic values in the script | Hard Coded values will be replaced by a parameter so that the values can change from one iteration to other or from one user to other. |
| Dynamic values generated by the server is captured by the LR parameter which will be used at the later part of the script | Lr parameter receives the values from the predefined output source (may be text file or excel file) |
| Script fails if these dynamic values are not handled via correlation | Your test will not simulate real-time scenario without paramterization |
Even though, there are many differences but they have one similarity. Both the concepts use LR Parameter
| LoadRunner | Jmeter |
| Paid Tool but however community edition is available for 50 virtual users for training purposes | Open Source Tool |
| LoadRunner supports handful of protocols like HTTP/ HTML, Web Services, PeopleSoft, SAP, Mobile, Native Apps, .Net, Citrix and many more | Jmeter supports only below protocols
|
| Owned by MicroFocus | Owned by Apache |
| LoadRunner | Performance Center |
| Windows Based tool | Web based tool |
| Good for small teams | Good for big teams |
| Vusers cannot be shared across multiple teams | Vusers can be shared across multiple teams |
7)What is Work-load Modeling?
Work Load Modeling is popularly known as WLM among Performance testers. WLM is used to calculate the pacing for a particular script against the popular belief that it is used for calculating the number of users.
Yes, it can used to calculate the users but for that we need to consider pacing as either zero or some random number. Ideally, Number be users should be given by the client as part of your NFR.
Well, little’s law is used to do WLM.
Below is the little law..
N = X * (Rt + Zt)
- N = No. of Concurrent Users
- X = Throughput (TPS)
- Rt = Response time (Secs)
- Zt = Think Time
- Industry standard for Zt is 10 secs
- Rt + Zt can be considered as Script Execution Time
However, minor modification of Little’s law is used for calculation of pacing
N = X * (Rt + Zt + Pacing)
8)What are the scripting standards that you have used?
- Make sure Author name, Script Name, Recording mode, Script Description is provided at the start of the script.
- Every single parameter name and variable name should follow naming standards that is defined by the organization.
- Every single piece of code should have appropriate comments
- Transaction name should follow naming standards
- Error handling should be done where ever possible
9)What kind of scripting challenges you have faced in your project?
Scripting Challenges while recording: Refer to this link from MicroFocus and look thru all the Problems from 1 to 5.
Scripting Challenges while Replaying: Major issues while playing back will be related to correlation. Identifying the correct values to correlate will be biggest challenge. If not identified correctly, your scripts will fail.
Other than above there will be many more challenges. I will share one such incident. Inspite of trying all possible options, script didn’t record. So, I had to record the web traffic using a tool called fiddler. Then I had to import this fiddler script into vugen and convert it into Vugen script.
10) What kind of challenges you have faced in controller?
Test Data: Most of the issues that you face in controller will be related to test data. Transactions will fail because of following
a) Bad data or incorrect data
b) Data provided is not enough
c) Using the setting like UNIQUE
LG’s:
a)Before start of the test, required LG’s needs to be connected and status of each LG should be “Ready”. Else, execution fails
b)If you are trying to get more users than the LG’s can support, then response times of the transactions will be effected.
Issues with scripts:
Typically multiple scripts will be executed together as part of scenario in the controller. Let’s say , you are running the test with 40 scripts. Even if there is an issue with one script, whole test needs to be stopped, identify the issue with the script and rerun again.
Sometimes, correlation issues will not be identified when run from VuGen. Especially, when you don’t test it with multiple data. These kind of issues will surface when running from the controller.
11)How to create LoadRunner script from HAR file (of Developer tools or Http Watch or fiddler)?
12)what is your approach if the controller got crashed before collating the results?
A) https://youtu.be/KGHmH7cj4hw
13) Does Analysis summary report capture the thinktime which is placed inside the trx – cont..?
Course Features
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- Duration 10 weeks
- Skill level All levels
- Students 0
- Assessments Yes
