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Website Performance And Load Testing

Your company is rolling out its new webTesters who are proficient in programming may
application. This web application is wellwant to manipulate their scripts by editing
designed and attractive. It has been wellthe code. These testers would work with code
tested by your quality assurance group. Youwritten in a well known programming language
have spent a lot of money marketing your newsuch as JavaScript, VBScript or C. Once your
website. The website now goes live. Very soonscript has been created, you may wish to put
you realize that your new web application isspecialized checks in place. These checks
unable to scale to your typical productionwould typically be related specifically to
load and the response times and performancethe application under test. For example you
reach completely unacceptable levels. Yourmay wish to check that the response returned
web logs indicate that most of your websiteby a certain web request meets certain
visitors simply leave the new website beforetextual criteria. This would involve the
buying anything since its response times areplacement of a text checkpoint. A text
very poor. You start to panic, and one ofcheckpoint can verify that a given text
your friends tells you that the reason yoursegment is present or is not present in a
application does not perform adequately isspecified portion of the web page. Once you
that you do not have ample hardware. Hearinghave finished the creation of the script you
this, you decide to add more server hardware.would typically test the script on your own
While this has a small effect on the websitemachine as a single user to ensure that the
response time, it is still woefullytest script runs as intended. You are now
inadequate. You soon realize that problemready to perform a performance based load
does not really lie with the hardware buttest. A good load testing tool will allow the
rather with the web application itself. Ittester to fine tune the execution of the
appears that your web application was nottest. This means that it will allow the
well optimized for the typical peak loads. Ittester to choose the number of concurrent
becomes increasingly evident that most ofvirtual users, how the script ramps up, how
your marketing dollars were wasted. Enter theit ramps down and for how long it runs. It
world of performance and load testing. Inshould also allow the tester to create
order to ensure that your application scalesvarious groups of concurrent virtual users
as the load increases, it is necessary tothat have their own ramp up, steady state and
perform tests where your application isramp down characteristics. A good testing
tested against a simulated load that closelytool will allow the user to distribute this
resembles the actual load that it will beload over several machines since a single
subjected to when it is exposed to themachine may be only able to scale up to a few
outside world. It is important to distinguishhundred users. To understand the behavior of
between functional or regression testing andthe loaded web application, it is also
load or performance testing. Functional andimportant for the load testing tool to enable
regression testing is used to automate athe tester to track the performance
large number of scenarios to ensure that yourcharacteristics of external components such
website works as intended. Load testing onas operating systems, web servers, databases
the other hand gauges how well your websiteetc. This allows the user to see how the
performs when it is subjected to a largeperformance of his application correlates
load, such as a large number of simultaneouswith the performance characteristics of the
users. Load and performance testing requireexternal component. This kind of analysis
the use of automated testing tools. It iswill allow the tester to pinpoint the root
impractical if not ridiculous to try tocause of performance bottlenecks fairly
simulate a load of 200 concurrent users byeasily. During test execution the tester
having a group of 200 folks sit on 200should be able to view the performance graphs
machines and try to perform operations at thein real time for performance metrics such as
same time. Before you can begin any kind ofthe transaction response time, HTTP responses
load and performance testing you will need toper second grouped by HTTP code (e.g. 200,
identify the test scenarios you need to404, 500 etc), passed transactions per
automate. A load testing tool will typicallysecond, failed transactions per second, total
record web requests and responses based ontransactions per second, hits per second,
user interactions with a website. As youpages downloaded per second etc. The tester
perform various operations on your website orshould also be able to simultaneously view
application, the tool records all the webthe performance characteristics of the
transactions that take place. When you finishexternal components described above. For an
recording, it generates an automated script.operating system this could be something like
Alternatively you could use the tool tothe % processor time, for a database it could
manually create the script. Typically testersbe the number of writes per second. At the
will perform a combination of the two. Theyend of the test, the tester would typically
will use the recording mechanism to generatebe able to view and save this data as a
the skeletal foundations of their scripts andreport for further analysis. Load and
then manually modify the scripts to take intoperformance testing allow you to simulate the
account specialized scenarios. The loadbehavior of your application under a typical
testing tool should also allow the tester toproduction environment. This will allow you
simulate constrained bandwidth situations.to plan your hardware deployment strategy
This means for example that it wouldeffectively and ensure that your application
accurately model users who would use thewill deliver the expected performance
application on a slow modem connection. Itcharacteristics. Rolling out a web
should also allow the tester to drive theapplication without testing its performance
script using random data from large externalcharacteristics under expected production
data sets. Load testing scripts can be eitherloads would resemble crossing a road
graphical or textual in nature. Good load andblindfolded. Load testing is an essential
performance testing tools do not require thepart of the development cycle of a web
testers to be programmers. Testers that areapplication  and  should never be overlooked.
not familiar with programming will work with
scripts that can be graphically manipulated.Umair Khan is Founder and Chairman of
Graphical scripts will typically show allVerisium, Inc., a maker of vPerformer, an
recorded steps in the form of a hierarchicalapplication for performance and load testing
structure and testers would modify any of theof web applications.
steps in order to modify the recorded script.



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