Load Runner Methodology to Performance Testing

International Journal of Trend in Scientific Research and Development (IJTSRD)
Volume 4 Issue 2, February 2020 Available Online: www.ijtsrd.com e-ISSN: 2456 – 6470
@ IJTSRD | Unique Paper ID – IJTSRD30155 | Volume – 4 | Issue – 2 | January-February 2020 Page 878
Load Runner: Methodology to Performance Testing
Ashish Kumar
Performance Engineer, Tata Consultancy Services Ltd, Mumbai, Maharashtra, India
Email: ashish.ksinha@yahoo.co.in / ashish.k40@tcs.com
ABSTRACT
The paper covers the most important part of testing which is essential for
testing the performance of application before going ‘Live’. In my research and
analysis with Microfocus owned tool ‘Load Runner’, we will discuss about it
deals with web based application and approach to calculate transaction per
hour (TPH) for test execution. As tool supports many protocols based on the
nature of application. Performance testing is used to analyze the real time
response time for business transaction. Application be constant with
increasing load or with simultaneous users should not affect the performance
of the application, is our main motto as a Performance Tester/Engineer.
KEYWORDS: Performance Testing, Load Runner, Performance Center, Virtual
Generator, Transaction, Load Runner Analysis
How to cite this paper: Ashish Kumar
"Load Runner: Methodology to
Performance
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International Journal ofTrendinScientific
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/4.0)
I. INRODUCTION
Application Performance Testing is all about the
performance and qualityoftheapplication.Theperformance
testing will insure the behavior of application under their
expected workload. Performance testing is a type of Non-
functional testing, which simplifies that these testing has no
relation with the functionality of the application. The
performance testing is done for a web application for its
speed, scalability andstability(S^3).Thegoalofperformance
testing is not to find bug and fix them; it is moreover for
elimination of performance bottlenecks.
Performance testing come in light when some unexpected
cause start arising even after Manual or functional testing.
Many companies loses its credibility as the unexpected
behavior of application come in picture in production
environment when sudden increase in real time user, end
user, back office or admin hits the application. To overcome
this big challenge, Performance testing play a vitalrole.Itis a
tool based testing where the tool records the events of
request and re-play it with simulation of different users,just
say real time virtual user.
II. TYPES OF SOFTWARE TESTING
Fig1: Types of Software Testing Fig2: Types of Performance Testing
 Load Testing – In load, testing application has been
checked under various load to test any bottleneck of the
application.
IJTSRD30155

International Journal of Trend in Scientific Research and Development (IJTSRD) @ www.ijtsrd.com eISSN: 2456-6470
 Stress Testing – In stress testing, web application is
checked under extreme workload to see the breaking
point of an application.
 Scalability Testing – It is used to check the load with
increasing number of user of an application, and it is
helpful in increasing the capacity of software system.
 Volume Testing – In volume testing, large number of
data is stored in database and overall web application
behavior is observed. It checks the correctness of an
application under varying database volume.
 Spike Testing – When there is sudden large spikes in
the load generated by users, then spike testing is done.
III. Software Testing Tool – Load Runner
Load Runner is software-testing tool owned by Micro Focus.
Load Runner is a best tool as per market survey, which
simulates user activity by generating messages between
application components rather than simulating interactions
with the user interface such as keypresses or mouse
movements.
HP acquired Load Runner as part of its acquisition of
Mercury Interactive in November 2006. In Sept 2016,
Hewlett Packard Enterprise announced it is selling its
software business, including Mercury products, to Micro
Focus. As of 01-Sept-2017, the acquisition was complete.
Components of Load Runner
 Virtual Generator
 Analysis
 Controller
 Load Agents
 Agents Process
 Recording
Fig3: Components of Load Runner
When you start the recording in Vugenfora newapplication.
Record the same business flow twice that will help in
comparing both vugen scripts and an easy way to find out
the dynamic values. Once we a list of dynamic values,wecan
easily start correlation. Correlation in Load Runner is
defined in two ways as automatic and manual correlation.
Suppose we had a dynamic value ‘ABC001”, when you are
validating the same in code generation, you will have Left
and Right boundary e.g. 78_LR_ABC001-XX. In this example,
70_LR_ will be left boundary and _XX will be right boundary.
Any dynamic value in this boundary will be captured
through tool.
 Why Load Runner?
Traditional way of testing approach is known as Manual
testing which offers partial solution to load testing. When
Client/Product owner wants to ensure that what load their
application can sustain, load based testingcameintopicture.
In addition, to reduce the high count of engineers toperform
manual testing, Load testing gives the entire solution for
performing this type of testing.
Fig4: How Load Runner works
IV. Automated Performance Testing
With the direct approach to perform the test using Load
Runner, you can optimize resources, best suggestion for
hardware configuration, and the best network requirement
based on application architecture, and debugging the
transaction response time based on agreed service level
agreement (SLA’s).
 Planning & Identification of Key business Area in
Performance Testing
A user requirement is translated to performance objective
for observing realistic behavior of application. In planning
and drafting the performance test plan, we need to
understand the key business area and their impact on
complete business flow of particular LOB based application.
Test plan need to complete with the current and projected
user specified objectives, which comprises the current
statistics of production. For designing the plan, we must
understand the architecture of application and we should
have strong knowledge to compare the production details
for apple-to-apple comparison.
 Defining the Data
You need to define what data is required onwards to
perform the test. The data can be created dynamically, or
making a clone of master user, or writing few interesting
creation query in Database. By using realistic data/user, you
can create accurate load test.
 Defining Testing Approach
You should have depth knowledge in creating the strategy
for testing applications. You can choose any type of
performance testing, say as Load, Stress, Capacity, Volume,
Spike, etc based on the user requirement.This typeoftesting
can be performed with Load Runner.
 Making of Performance Scripts
When you are good with the above steps, we need to record,
enhance the scripts for completed flow. You need to write
lr_start_transaction (); beforetheparticularwebrequest and
lr_end_transaction (); after completion of that request. This
function will count the response time of web request for
transaction, which will be helpful in comparing the same
with agreed SLA’s. For enhancing the script, any value you
enter via keyboard at the time of recording needs to be
parametrize and any dynamic value you observed in code is
to be correlated.
 Test Scenario and Execution

Once the test script is ready and validated with few
iterations (Say 5) and different user, script should be
uploaded in Performance center / controller.
We need the make the scenario for our test executions.
 Dedicated Load generator is to mapped accordingtothe
number of Vusers which you are going to test.
 While making the scenario, ramp up and ramp down
should be given and a steady state of run must be
mention as per requirement.
 Monitor varieties of graph while running the execution
We need to enable run time settings with our requirement.
1. TPH (Transaction Per Hour)
Little law states the formula as below
Number of Vusers = TPH * (Pacing + Think time) / 36000
2. Logs
When we run the test in performance center, we need to
disable the full logs. Why? Because it will write the logs
which will require memory. In addition, if your test is of
higher virtual users, it will write full logs. So recommended
way is to disable the full logs and write the logs only if error
occurs.
3. Pacing/Think Time
With the help of little law, calculate the pacing/ think time
desired for your execution
Rest other options will be treated as per the project
requirement.
 Report And Analysis
Once the execution is completed, download Load Runner
analysis (.lra) file from PC. Open LRA file in Analysis
component of LR. There you can see some pre-defined
graphs, and you can select more graph based on your
client/project requirement. It is recommended that select
some customized report template, and add flavors based on
your requirement and generate the report.
V. TRADITIONAL APPROACH TO CALCULATE
FORMULA
Little Law:
Little’s law named after “John DuttonConantLittle”whowas
Renault Professor at the MIT. It states the numberof request
in system (closed) is equal to the product of averagenumber
of Requests serviced per unit time and theaveragetime each
Request stays in the system.
Numerically,
N = (R + ThinkTime) * X
Where,
N = average number of users in a system
X = average throughput or departure rate of users
R = average time spent in the system or response time
VI. EXPERIMENTAL APPROACH
Based on the little law approach, we had
Average Number of users = (Average Time + ThinkTime) *
Average Throughput
Additionally, we can talk more about simplifying this
formula with all other timing required to manipulate the
formula is think time, pacing, average response time with 1
iteration, etc
No. of users = {(Average Response Time in 1 iteration +
Pacing Time + Think Time)* TPH}
On dividing the result with 3600, we will get the response in
seconds (TPS). Remember TPH means transaction per hour.
The numerical explanation for little law is explained as
below in spreadsheet formula
Many performance engineer/tester believes whatever the
result they get is accurate, but it does not be!
For example, if you run a Load Runner test of 1000
concurrent users, Load Runner will give some results.Never
assume the given result is 100% accurate. Always it is
recommended to cross verify the results using the formula
stated above.
Let us say, TPH is 50 and Avg. response time including think
time is 15 seconds.
Number of users = 50*15 = 750
However, our expected result was 1000,somethingis wrong
here!  So we need to place the count with the formula stated
above (refer spreadsheetpicture above) to calculate the
accurate measurement.
Reference:
[1] https://en.wikipedia.org/wiki/Load Runner
[2] https://www.softwaretestinghelp.com/Load
Runner/Load Runner-scripting-challenges/
[3] https://www.softwaretestinghelp.com/LoadRunner/hp-
Load Runner-tutorial-8/
[4] https://www.perftesting.co.uk/performance-center-
architecture-overview/2011/08/24/
[5] https://perfmatrix.blogspot.com/p/hp-Load
Runner.html
[6] https://www.guru99.com/understanding-vugen-in-Load
Runner.html
[7] https://www.softwarehour.com/Load
Runner/parameterization-Load Runner-step-step/
[8] https://www.tutorialspoint.com/Load
Runner_online_training/Load
Runner_parameterization.asp
[9] http://www.geekinterview.com/question_details/15651
[10] http://nonfunctionaltestingtools
.blogspot.com/2015/01/verifica
tions-and-error-handling-
in.html
Mr. Ashish Kumar, an engineering
graduate from VelTech University,
Chennai in the field of Electronics &
Communication Engineering. After
completing his degree, he worked in
IT companies like HCL, Accenture and currently working

with TCS on the role of Performance Engineer. Hehas expert
knowledge in performance testing tool Load Runner with
multiple hands on experience in monitoring tools.

Load Runner Methodology to Performance Testing

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