Q101.
How Do You Perform Functional Testing Under Load?
Answer
:
Functionality
under load can be tested by running several Vusers concurrently. By
increasing the amount of Vusers, we can determine how much load the
server can sustain.
Q102.
What Is Ramp Up? How Do You Set This?
Answer
:
This
option is used to gradually increase the amount of Vusers/load on the
server. An initial value is set and a value to wait between intervals
can be specified. To set Ramp Up, go to ‘Scenario Scheduling
Options’.
Q103.
What Is The Advantage Of Running The Vuser As Thread?
Answer
:
VuGen
provides the facility to use multi-threading. This enables more
Vusers to be run per generator. If the Vuser is run as a process, the
same driver program is loaded into memory for each Vuser, thus taking
up a large amount of memory. This limits the number of Vusers that
can be run on a single generator. If the Vuser is run as a thread,
only one instance of the driver program is loaded into memory for the
given number of Vusers (say 100). Each thread shares the memory of
the parent driver program, thus enabling more Vusers to be run per
generator.
Q104.
If You Want To Stop The Execution Of Your Script On Error, How Do You
Do That?
Answer
:
The
lr_abort function aborts the execution of a Vuser script. It
instructs the Vuser to stop executing the Actions section, execute
the vuser_end section and end the execution. This function is useful
when you need to manually abort a script execution as a result of a
specific error condition. When you end a script using this function,
the Vuser is assigned the status "Stopped". For this to
take effect, we have to first uncheck the “Continue on error”
option in Run-Time Settings.
Q105.
What Is The Relation Between Response Time And Throughput?
Answer
:
The
Throughput graph shows the amount of data in bytes that the Vusers
received from the server in a second. When we compare this with the
transaction response time, we will notice that as throughput
decreased, the response time also decreased. Similarly, the peak
throughput and highest response time would occur approximately at the
same time.
Q106.
Explain The Configuration Of Your Systems?
Answer
:
The
configuration of our systems refers to that of the client machines on
which we run the Vusers. The configuration of any client machine
includes its hardware settings, memory, operating system, software
applications, development tools, etc. This system component
configuration should match with the overall system configuration that
would include the network infrastructure, the web server, the
database server, and any other components that go with this larger
system so as to achieve the load testing objectives.
Q107.
How Do You Identify The Performance Bottlenecks?
Answer
:
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.
Q108.
If Web Server, Database And Network Are All Fine Where Could Be The
Problem?
Answer
:
The
problem could be in the system itself or in the application server or
in the code written for the application.
Q109.
How Did You Find Web Server Related Issues?
Answer
:
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.
Q110.
How Did You Find Database Related Issues?
Answer
:
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.
Q111.
Explain All The Web Recording Options? What Is The Difference Between
Overlay Graph And Correlate Graph?
Answer
:
Overlay
Graph:It
overlay the content of two graphs that shares a common x-axis. Left
Y-axis on the merged graph shows 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 X-axis of merged graph. Y-axis of the graph that was
merged becomes merged graph’s Y-axis.
Q112.
How Did You Plan The Load? What Are The Criteria?
Answer
:
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.
Q113.
What Does Vuser_init Action Contain?
Answer
:
Vuser_init
action contains procedures to login to a server.
Q114.
What Does Vuser_end Action Contain?
Answer
:
Vuser_end
section contains log off procedures.
Q115.
What Is Think Time? How Do You Change The Threshold?
Answer
:
Think
time is the time that a real user waits between actions. Example:
When a user receives data from a server, the user may wait several
seconds to review the data before responding. This delay is known as
the think time. Changing the Threshold: Threshold level is the level
below which the recorded think time will be ignored. The default
value is five (5) seconds. We can change the think time threshold in
the Recording options of the VuGen.
Q116.
What Is The Difference Between Standard Log And Extended Log?
Answer
:
The
standard log:it
sends a subset of functions and messages sent during script execution
to a log. The subset depends on the Vuser type.
Extended
log:it
sends a detailed script execution messages to the output log. This is
mainly used during debugging when we want information about:
Parameter substitution. Data returned by the server. Advanced trace.
Q118.
What Type Of Lr License Are You Using?
Answer
:
Term
Licensing for 1year with 500 Vusers
Q119.
Do You Have License For Protocols?
Answer
:
Not
sure.
Q120.
What Is The Process That You Follow Starting From Pt Requirements?
Answer
:
Identify
the Scenarios →
Plan the Load Test →
Design The load Test (Scripting the Vuser) →
Create the Scenario (Controller) →
Design Scenario →
Execute Scenario →
Monitor the Scenario →
Generate the Report →
Analyse the Report
Q121.
Is License Required For Vugen?
Answer
:
No.
Q122.
Is It Possible To Record With Ajax (click & Script) & Web
(click & Script) In Multiple Protocol Scenarios?
Answer
:
No.
Q123.
Which Protocol You Would Recommend For Testing Performance For .net
Applications Implemented With Ajax And Why?
Answer
:
Ajax
(click & script) OR web (click & script) OR MS.Net protocols.
Q124.
Imagine You Are Running A Load Test And After Some Time Controller
Generated The Error. What Will Be Your Reaction And What You Will
Observe?
Answer
:
I
will look into the Log message window in controller and identify why
the error is thrown & if needed I will make enhancement to my
Vuser script in Vugen and then run the script in debug mode to make
that the Vuser script does not fail and will refresh the script in
controller and the start the scenario back.
Q125.
What Is The Process Followed While Scripting In Vugen?
Answer
:
Identify
the protocol (protocol Advisor) →
create a new Vuser script by selecting the supporting protocol →
Record the actions with appropriate recording options →
Generate Script →
Run the script →
Identify the dynamic values and correlate all the dynamic values and
run the script
Q126.
Explain Correlation Process.
Answer
:
Correlation
is a technique to handle the dynamic values generated by the server
like session id's or serialization id's by replacing them with the
current values generated during the run-time.
Q127.
What Type Of Monitors Have You Setup?
Answer
:
I
worked with various monitors at App server level and monitors of
windows resources of the servers and few monitors at db level.
App
server monitors –JVM
size, Connection ppol, GC, Heap size, free memory etc.;
Windows
resources –CPU
utilization, processing time, Process, Virtual memory, page faults
etc.:
Db
monitors –Top
time consuming sql's, poor indexes, dead locks, etc...
Q128.
What Type Of Servers Have You Worked On?
Answer
:
Worked
on App servers like Weblogic, Jboss, MS-IIS 6.0 and db servers like
DB2 and sql server.
Q129.
For A Typical Pt Project, What Type Of Documents Do You Expect For A
Client ?
Answer
:
Documents
related to the High level and low level architecture of the
application. Design documents and documents that describe the usage
of third party components and external communication components and
documents that describe the communication architecture of the
application and use cases and test cases of the business critical
scenarios and documents related to the system service levels and
documents of h/w , s/w re's etc......
Q130.
What Types Of Bottlenecks Have To Identified In Your Latest Project ?
Answer
:
Poor
GC, constant high usage of VM, connection pools, poor indexing and
complex sql queries etc.
Q131.
What Is The Response Time For The Application That You Have Tested In
Your Recent Project?
Answer
:
It
varies from business scenario to business scenario, the response time
for critical business scenario is 3 sec's.
Q132.
What Are The Recommendations That You Have Provided For The Client?
Answer
:
Poor
GC, constant high usage of VM, connection pools, poor indexing and
complex sql queries etc.
Q133.
What Are The Challenges You Have Faced Till Now In Pt?
Answer
:
To
simulate the load on EJB applications that uses RMI protocols over
IIOP.
Q134.
What Is The Difference Between Load Testing And Endurance Testing?
Answer
:
Load
Testing – Test objective is to find the application behavior is
terms of response time under anticipated load.
Endurance
– Test Objective is to simulate load on an application up-to a
period of time to monitor the application performance for longer
periods.
Q135.
How Many Controller And Lg Machines You Have?
Answer
:
1
controller and 4 load generators.
Q136.
Do You Test At Offshore Or On-site?
Answer
:
Offshore
Q137.
What Type Of Settings Have You Done For Web (click & Script)
Protocol?
Answer
:
Change
the Event configuration Level, Select appropriate mode(GUI/URL/HTML)
etc..
Q138.
Suppose While Recording In Web (http) Protocol, You Could Not
Correlate Dynamic Values. What Will Do?
Answer
:
Will
look into the Response Log of the function while recorded.
Q139.
What Differences You Observed Between Lr 8.0 & Lr 9.5
Answer
:
Protocol
Advisor, Parameter Simulator, Business process report, User defined
template.
Q140.
What Are The Differences Between URL Mode And HTML Mode And In What
Context You Choose One Over Another While Selecting Protocol For
Recording?
Answer
:
The
HTML-based script level generates a separate step for each HTML user
action. The steps are also intuitive, but they do not reflect true
emulation of the JavaScript code.
The
URL-based script mode option instructs VuGen to record all browser
requests and resources from the server that were sent due to the
user's actions. It automatically records every HTTP resource as URL
steps (web_url statements). For normal browser recordings, it is not
recommended to use the URL-based mode since is more prone to
correlation related issues. If, however, you are recording pages such
as applets and non-browser applications, this mode is ideal.
Q141.
Suppose You Are Running A Scenario In A Controller And In The Middle
You Want To Ramp Up 20 Vusers. Is It Possible?
Answer
:
Yes
we can ramp up the Vusers.
Q142.
How Will You Define The Complexity Of A Performance Scenario?
Answer
:
Usually
by looking at the number of transactions & the no of
correlations.
Q143.
What Is Correlation?
Answer
:
Correlation
is a technique to handle the dynamic values generated by the server
like session id's or serialization id's by replacing them with the
current values generated during the run-time.
Q144.
What Is Sprintf() ?
Answer
:
Writes
formatted output to a string
Q145.
What Is The Difference Between Recording Log, Generation Log, Replay
Log ?
Answer
:
Recording
Log: A Network Analyzer would analyze the communication happing at
network level and logs the events.
Generation
Log: Logs the events happening while generating the Vuser script
after recording.
Replay
Log: Records the events of happening when executed a function in the
script. Will be logged at each line level of the script.
Q146.
As You Employ The Settings Of Logging(standard, Extended) For A
Script In Run- Time Settings, How Do You Do This Using Code?
Answer
:
lr_set_debug_message(LR_MSG_CLASS_EXTENDED_LOG,
LR_SWITCH_ON)
lr_set_debug_message(LR_MSG_CLASS_EXTENDED_LOG,LR_SWITCH_OFF)
Q147.
What Is The Definition Of Ajax ?
Answer
:
Asynchronous
JavaScript and XML.
Q148.
What Are 2 Functions To Stop A Script (one Lr Function And C
Function) ?
Answer
:
lr_abort()
; lr_exit() ;
Q149.
What Is A Rendezvous Point & If You Insert A Rendezvous Point In
Your Script, What Settings Do You Employ In Your Scenario ?
Answer
:
Will
Define the Rendezvous Policy in Scenario settings.
Q150.
What Is Ip Spoofing? Why Do We Use It ?
Answer
:
When
testing using Web and Win-socket protocols, by default Vusers on each
host machine use the host's (agent's) IP address. Since a particular
server keeps serving a specific IP address, load tests would reflect
network router caching and other optimizations rather than the
real-life situation where different users arrive to the server with
different IP addresses. This is especially needed when the hardware
configuration under test balances load across a "farm" of
several (web or database) servers. "IP spoofing" enables
each host machine to "spoof" the server into thinking it is
using many different IP addresses.
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