Quick Test Professional (QTP)

During replay, the script will then be replayed like a Windows VB Script, launching the windows and activating the buttons as what is being recorded.  A sound knowledge of VB script is actually helpful in maintaining the scripts however not necessarily needed as QTP is relatively easy to use.  A tip here is you can actually use VB script in Windows to run automation without even using QTP.  It works the same way but a little low-level work is required and you need to understand the various ways the windows and objects are called in the Windows environment.

In QTP, you can add check points to determine if your application response as intended.  You can also use output values similar to the concept of correlation in QTP to handle dynamic data.  The output values are also used to be input values for the next step depending on how the test case is designed.

As for the licenses, they worked in two ways.  Either you use a Seat license or a Concurrent license.  The seat license is tied to the machine that installed the license while the concurrent license requires a license server to be available for it to retrieve the license information.  The license will decide the type of application you can record; generally called an Add-In.  QTP has various Add-In to suit the needs of the customer.  The common one is Web, Java script and ActiveX.  Other supported technologies that require an Add-In are Java, Oracle, SAP, etc.

Of all the virtues of using QTP, you will still need to be careful on the following and use it correctly:

• Resolution of the recording machine and replay machine MUST be the same – QTP rely on the resolution of the machines to recognize the coordinates and size of the objects.  Problem will arise when the resolution of the recording machine and replay machine is different.  Example, the script was recorded in 1024 x 768 resolution while it was replayed in a 1280 x 800 resolution may result in the script generating error as the objects have changed their coordinates.
• Iteration of the script requires the start and end point to be the same – For a script to iterate successfully, the script should be recorded in a way that the start and end point are the same.  Example, the script starts off with the login page and proceeds with login and some activities then logout to return to the login page.  In this manner, the script will be able to iterate with the next set of value such as a new login account.
• Context-sensitive – Context sensitive menus may require the use of Object Spy feature in QTP.  Context sensitive menu such as mouse-over menu that will show the sub-menu.  This will require pressing “Crtl-Key” when using the Object Spy and inserting the action (and object) into the script.  However, we recommend recording in a lower granularity (in analog) to capture as much objects as you can before proceeding to use the Object Spy.
• Preparation of initial test data – Most often people ignored the need for a baseline set of data for testing.  After each functional (regression) test, the data needs to be refreshed to a clean set before the script can work again.
• Still dependent on a well-designed test case – To make the tool really useful, the tool still highly depends on a well-designed test case.  Without a well designed test case, the downstream activities such as recording and modifying may not serve its purpose well.

The information should give you an overview of how QTP works and what you should take note after purchase (or even before purchase).  We hope that it will be useful to you and do share with us on anything related to QTP.

Of course, its not free.  To request an evaluation or see JSS pricing see the JSS Request page.  For more information of this extension, you can refer to the provider’s website at Zyntax Consulting.

About Zyntax Consulting, refer to Zyntax Consultin, About Us.

(Special thanks to Aravind Kumar for contribution, CSS Corp)

As both LoadRunner and SilkPerformer offers the same functionality, what SilkPerformer is appealing is it handles load test in a project approach. With this approach, each load test is saved as a project with various settings of profiles and workloads. This is a great feature when you want to track the load test from a customer/project perspective. Furthermore, within a project, for every load test that was executed, a result directory for each run is created. This is useful in tracking the number of runs that were conducted. In this way, there is a structural approach in managing the tests that were conducted (especially useful when you are running multiple load test). As for LoadRunner 9.0, an additional scenario profile setting was introduced in Controller. This feature allows the different configuration of scenario profiles similar to SilkPerformer. Whereas the generation of a results directory in LoadRunner remained the same in the Controller results setting.  SilkPerformer has another great feature, which is resource management of the load generator. By defining a pool of load generators, the load tester is able to have an overview of the resources that is participating in the load test such as if any load generators are being over-worked. This is almost similar to the Resource Pool in Performance Center and is not available in LoadRunner.

During the execution, SilkPerformer allows monitoring of the resources in terms of CPU usage in the Load Generator. This is beneficial when differing problem in resources on the Load Generator or the SUT itself. Furthermore, feature allows capacity planning for load generators. SilkPerformer also allows monitoring on the progress of the vusers in terms of percentage completed by each vuser. This is a great feature that allows the load tester to estimate the duration of the load test and forecast the end time of the load test.

For verifying replay of script, the Silk TrueLog used in SilkPerfomer has better capabilities than Vugen Runtime Viewer. If offers replay of the screens and providing views of the data in and out from the client and server with one single component instead of toggling with runtime viewer and client-server request views.

SilkPerformer allows monitoring similar to LoadRunner. However, as compared with LoadRunner, it has better control and ease-of-use in setting up monitors. On top of this, SilkPerformer requires additional logging for non-default monitors unlike LoadRunner, which automatically logs the data when the counter is been added into the monitor list. Also, SilkPerformer is restricted to a defined set of custom monitors namely JMX, SNMP, Perfmon and Rexec unlike LoadRunner, which provides more monitors.

SilkPerformer utilizes Silk Performance Explorer for analysing. However, it’s capability to merge, manipulate, handle external data is not as flexible and robust as LoadRunner Analysis. The analysing feature is an important component used by the Performance Team to determine problem causes.

SilkPerformer have the similar license mechanism as LoadRunner, which is bounded by a single host. However it features an additional mechanism that allows the option to “check-out” license to the installed application. This is useful in an organization context in managing our performance test in different environments and will be discussed in a later article.

Performance Center

Performance Center is designed to manage load tests in the concept of projects (or load test projects). And for each project, you are able to trace the number of runs pertaining to each individual project. Privileges such as Administrators, Consultants, Tester and Managers are also introduced in Performance Center. Administrator role maintains the Performance Center setup as a whole and has the rights to manage the resources, determine the maximum number of concurrent users the project can generate. While privileges for users such as Consultant, Tester or Manager can be configured depending on the organization requirements.

Through Performance Center, Controllers and Load Generators can be managed together as a pooled resource via a single point of control. In this way, resources are better utilized. Furthermore, there can be configurations to limit the usage of Load Generators to the projects assigned.  License entitlement (or enforcement?) is increased with one more layer of control. the amount of concurrent runs and the total number of vusers that the Performance Center can generate. As it is an enterprise version of LoadRunner, the LR license engine still applies, such as the number of vusers, the protocols and monitors entitlement. Both Performance Center and LR licenses are needed in order for the full Performance Center to function properly.

Technically, Performance Center is an enhanced web version of LoadRunner. The internal infrastructure is built on DCOM links that needs to exist in the same LAN. Another thing to note is that Performance Center maintains a database that keeps information of the load tests as well as the configurations of the setup.

The basic infrastructure of Controller and Load Generator still applies even after migrating over to this software. Therefore, the troubleshooting for LoadRunner, tips and tricks still applies for them. For the Controllers and Load Generators, they can be located in a separate LAN. PC comes with a nice feature of managing the resources such as patch updates and restarting function over the interface.

VUGen and Analysis remains the same as a client-side program. Performance Center provides these two components by making them downloadable in its download web pages through a download link. This page, with the right ASP knowledge, can be configured to include other downloads.

With all the above mentioned, being an enterprise version of LoadRunner means more user usage and more features which coherently means more money to pay for by the organization. Therefore, conduct some evaluation before jumping into the decision of purchasing this behemoth product.

To sum up, Performance Center is an enhanced web version of LR with the capabilities of running multiple load tests instead of a single load test. It is managed in projects and can be traced to the number of runs. The licenses have increase to one additional layer in controlling the total number of concurrent runs allowed. Before jumping into this product, do an evaluation if there is a need for this product in the organization.

Bugnux

The project’s goal is to provide a LiveCD Linux distribution that is also installable, packaged with useful Testing Tools to help testers and quality assurance personnel. The distribution will consist of Open source Tools for testing web application, Java, load and performance. This will be useful for testers to quickly test applications without the need to install a complete OS, using any pc. This would be especially useful if they need to validate features on linux. Distribution will also be handy for consultants who have limited resources and want to test with tools they are most familiar with. It will also aid companies to quickly provide a standard linux system with testing tools to consultants or temporary testers. The goal is to add as many useful and usable open source testing tools that will be essential for testers and quality assurance personnel to do a good job with minimum time wasted in downloading and installing necessary operating system and essential software in a downloadable ISO format which would fit in a CD or USB stick.

Tools included are listed below.

Java GUI applications

Jacareto – Jacareto is a capture & replay tool for programs written in Java. You can capture actions on applications and replay them later on (like macros). Jacareto can be used for:

• GUI tests
• Creation of animated demonstrations
• Creation of macros
• Qualitative and quantitative analyses of user behavior

There are two front ends included in Jacareto:

• CleverPHL is a GUI front end for Jacareto
• Picorder is a command line front end for Jacareto

Documentation and CleverPHL can be accessed from kmenu start on the desktop.

Marathon – A GUI testing framework supporting applications developed using Java/Swing. It can be used to capture user interactions on the applications and also insert assertions to verify that correct processing is taking place. The generated raw script which is in jython, can be refactored to modules for efficient reuse and maintainability. Replay the scripts either manually or integrate Marathon into your build process for automatic execution of the test suites.

Documentation and Marathon can be accessed from kmenu start on the desktop.

Other GUI applications

X11::GUITest , a Perl package intended to facilitate the testing of applications by means of user emulation. It can be used to test and interact (SendKeys, WaitWindow, etc.) with GUI applications; which are built (GTK+, Qt, Motif, etc.) upon the X library

Documentation can be accessed from kmenu start on the desktop – Tool itself can be used only via commandline.

Web-based applications

FunkLoad – A functional and load Web tester whose main use cases are functional testing of Web projects (and thus regression testing as well), performance testing, load testing (such as volume testing or longevity testing), and stress testing. It can also be used to write Web agents to script any Web repetitive task, like checking whether a site is alive.

Documentation can be accessed from kmenu start on the desktop – Tool itself can be used only via commandline.

Selenium is a test tool for web applications. Selenium tests run directly in a browser, just as real users do, and they run in Mozilla and Firefox. It can be used to do application functional testing and Create regression tests to verify application functionality and user acceptance. Selenium uses JavaScript and Iframes to embed a test automation engine in your browser. This technique should work with any JavaScript-enabled browser.

Tools is part of Firefox as an extension.

Performance/Stress

curl-loader – The loader is a C-written open-source community tool, simulating application load and application behavior of thousands and tens of thousands HTTP/HTTPS and FTP/FTPS clients, each with its own source IP-address. In contrast to other tools, curl-loader is using real client protocol stacks, namely, HTTP 1.1 and FTP of libcurl, TLS/SSL of openssl, and supports login and authentication flavors.  The tool is useful for performance loading of various application services, using HTTP, HTTPS, FTP, FTPS, web-sites testing, and traffic generation. Activities of each virtual client are logged and statistics provided: resolving, connection establishment, sending of requests, receiving responses, headers and data received/sent, errors from network, TLS/SSL and application (HTTP, FTP) levels.

Virtual clients are grouped to the so-called batches of clients, performing the same sort of activities. Configurable activities for the simulated clients are:

• authentication login;
• user activity simulation (UAS) by fetching several urls and timeouts in between;
• logoff.

The tool can be easily extended to generate telnet, tftp, ldap, etc other application load, supported by the great libcurl library.
Documentation can be accessed from kmenu start on the desktop – Tool itself can be used only via commandline.

Firefox extensions preinstalled include:

Console² , is used not only for JavaScript errors, but for CSS errors as well. This extension takes this into account by providing a simple possibility to display errors by type. It let’s you display errors filtered by type (Errors, Warnings, Messages), language (JavaScript, CSS, XML) and context (Chrome, Content). Furthermore it provides a simple search box (as seen in the History and Bookmarks sidebars) and some accessibility improvements.
Tool itself can be used from Firefox in Tools → Console only via commandline.

An essential extension/sidebar for web developers using Firefox, UrlParams conveniently summarizes all of your URL parameters into a readable and usable sidebar. It show the querystring from the last request to the server. Sure, you can see the same info with LiveHTTPHeaders, but the layout of this extension is a show-stopper!

Selenium is a test tool for web applications. Selenium tests run directly in a browser, just as real users do, and they run in Mozilla and Firefox. It can be used to do application functional testing and Create regression tests to verify application functionality and user acceptance. Selenium uses JavaScript and Iframes to embed a test automation engine in your browser. This technique should work with any JavaScript-enabled browser.
Tools is part of Firefox as an extension.

Molybdenum is an inbrowser test tool for websites. Molybdenum is realised as a Firefox extension. As Molybdenum is running as an extension in the browser, it can access the content of a loaded webpage directly and doing checks and triggering actions. It is based on Selenium and enhances it with direct browser integration and a visual editor. At the same time it removes the need to deploy testscripts on the server to be tested. The goal of Selenium to support multiple browsers is secondary for Molybdenum. Molybdenum tries to utilise the special features of Firefox Extensions.

Tools is part of Firefox as an extension.

Server Switcher allows you to easily switch between sites on your development and live servers, so that you can immediately see the differences.

Use case: When you are on http://localhost/page.html (your development server) and click the Server Switcher icon you will instantly be redirected to http://www.yoursite.com/page.html (your live server). (“localhost” and “www.yoursite.com” are of course configurable – you can also create multiple development/live-server-pairs.)

CookieSwap is a Firefox/Mozilla extension that enables you to maintain numerous sets or “profiles” of cookies that you can quickly swap between while browsing.

CookieSwap allows you to swap all your cookies out of the browser’s memory and swap in a new set of cookies. This is useful for tasks like:

• Changing your cookies/identity to web e-mail sites (like Yahoo, Gmail, Hotmail, etc) so that you can quickly look like different users. Nice if you maintain multiple accounts and are tired of logging out and then back in to switch accounts. Also nice if two people are using the same computer and want to switch between accounts quickly.
• Changing your cookies/identity to see how sites like Amazon and Google treat you differently depending on who you are. For example, if Amazon recognizes you as a returning shopper they give you a different looking page (and there were claims that they give you different prices also). Google has begun to use a feature called “Personalized Search”, where they modify their search results based on your user identity. There is a question about this when you create your Google account. The results of Google searches are different depending on if Google knows you or not. Use CookieSwap to quickly swap between Google recognizing you and being anonymous. Run the same search and see the differences.
• If you test web sites, you can setup numerous cookie profiles to look like different types of users and swap between those users quickly and easily to test your site in numerous modes

DOM Inspector is a tool that can be used to inspect and edit the live DOM of any web document or XUL application. The DOM hierarchy can be navigated using a two-paned window that allows for a variety of different views on the document and all nodes within.

Features:
- Up to 5 statusbar panels;
- Request and response headers;
- Custom headers;
- Tooltip headers;
- Menu with headers for statusbar panels;
Requires:
- Live HTTP Headers;
Help:
- Quick reference to HTTP headers;

LiveHTTPHeaders adds information about the HTTP headers in two ways:

• First by adding a ‘Headers’ tab in ‘View Page Info’ of a web page.
• Second by adding a tool in the ‘Tools->Web Development’ menu to be able to display http headers in real time (while pages are being downloaded from the Internet.
• Third by letting you edit request headers and replay an URL (beta). Look for the Replay button in the live window!

This project may be of some help for the following:

• Help debugging web application.
• See which kind of web server the remote site is using.
• See the cookies sent by remote site.

For more info visit URL: http://www.bugnux.org

Downloads LiveCD: bugnux – LiveCD download

SEATTLE, WA, May 27, 2008 – J9 Technologies Inc. today announced a new solution in its JDBC Protocol Add-in product line, enabling customers to extend the capabilities of HP LoadRunner, to stress and isolate problems in the backend data tier and deploy new applications with confidence. J9 is a member of the HP Quality Management Ecosystem, which provides alliance members the ability to develop test accelerators for HP Quality Center and HP Performance Center to support additional platforms, applications and environments.

The JDBC Protocol Add-in leverages HP LoadRunner technology, capturing all SQL traffic going from a Java application to the backend database and playing it back to directly exercise the data tier for high concurrency testing. This helps QA teams apply a measurable and repeatable load to the database and expose potential performance problems early in the development cycle. The auto-generation of database testing scripts replaces the need for writing complex Java code and frees up QA resources for other QA activities.

The JDBC Protocol Add-in from J9 Technologies is fully tested with the full suite of HP LoadRunner solutions, and can easily be used alongside all other HP LoadRunner protocols to create a more realistic and comprehensive load test.  For the last 6 years, J9 Technologies has been working closely with HP to ensure that customers get more out of their HP LoadRunner and HP Performance Center investments,” said Clay Roach, President and CEO for J9 Technologies. “We are very excited about this latest addition in our new line of JDBC Protocol Add-ins and the value it will deliver to our mutual customers for simplifying their JDBC testing efforts. The JDBC Protocol Add-in can help reduce testing cycles dramatically and enable QA, Dev and DBA teams to collaborate on fine-tuning database testing.”

“HP is committed to helping our customers rapidly deliver critical business applications that function and perform according to the needs of the business,” said Erez Barak, director of product marketing, Software, HP. “HP’s collaboration with J9 helps our customers increase efficiency by streamlining the complex process of database testing.”

JDBC Protocol Add-in is available today, and is compatible with HP LoadRunner and HP Performance Center version 9.1 and up.

About J9 Technologies Inc.

J9 Technologies leads the field in application performance analysis and diagnostics. Working side by side with our clients, J9 consultants utilize proven methodologies to solve mission critical application performance issues and maximize the scalability of complex application architectures. As a certified Hewlett Packard partner and reseller, J9 consultants can also install and train clients to use HP’s best-of-breed monitoring tools in-house so that firefighting becomes a thing of the past. J9 fine tunes business to ensure peak performance, scalability and optimization so clients can focus on their bottom line. More information is available at the Products Page.

For sales talk which is not part of the scope here, you might want to refer to the official vendor website. Before we go further,the discussion here will be specified to performance testing (LoadRunner/Performance Center) and J2EE.

A Commander is installed to collect all the monitoring data from the probes. The processing of the monitoring individual probes are then performed on the Commander where you can view it via port 2006 on the browser. The Commander also servers as the centralizing the entire Diagnostics collecting the data from all the probes that is connected to it.

So with Diagnostics, how does it compliment LoadRunner? LoadRunner does not report specified/drill down to module-level, or provide information of problematic modules (that maybe causing the bottleneck). It only reports system bottleneck in a bigger picture, such as CPU, Memory, Network or Disk usage. With Diagnostics, you can go a step further by monitoring the memory usage of the application server, breaking them down to each module level.

For example, in a J2EE application launched from BEA WebLogic, the process that runs the application is a java.exe. From an OS-level monitoring perspective, we can only know the CPU, Memory or Disk utilization on the process level, or even further to a thread level. However, we do not know what are the internals that maybe causing the bottlenecks, such as Garbage Collection type and frequency, the amount of objects created in the JVM or the method in the JVM that is using the most processing time. As such, Diagnostics will come into play to fill up the gap.Through this implementation, you can work down from the server-level (OS) into the application-level systematically.

Troubleshooting; when the probes are not reporting the data back to the Controller (in a LoadRunner setup), it can be tied to various reasons. However, the main ones maybe caused by (1) unsuccessful or no instrumentation (remember, you need to instrument the application server after the installation), (2) ports between the Controller, Diagnostics and Probe are not opened, or (3) application server or Diagnostics server are not running When working with LoadRunner/Performance Center, always ensure that the Diagnostics setup is fully functional before adding the Diagnostics Module into the LoadRunner monitoring. This is an effective method in troubleshooting Diagnostics/LoadRunner integration problems in a load test setup.

Licensing; Diagnostics is bounded by (1) the number of probes that can be installed and (2) the number of Diagnostics Server that is been implemented. This license is solely used for Diagnostics only which should not be associated with the one in LoadRunner. In order for Diagnostics to work with LoadRunner/PC, an additional license used by LoadRunner called, Diagnostics Module License is required. This will allow the monitoring data from the Diagnostic server to be incorporated into the load test result.

To start familiarizing the Diagnostics Software (Probe and Commander), it will be advisable to spend at least two days to explore the features and getting used to the setup/instrumentation. BEA WebLogic offers free downloads (after you have registered) of their J2EE application server with a working example, Avitek Medical Record application server that can be used for your familiarization.

J2EE Diagnostics

1. The application servers are installed with J2EE probes.
2. Then after they are instrumented.
3. The statistics are then collected and sent to the Diagnostic Server which does the processing of the data.
4. This data is then sent to Controller to consolidate into the load test results. i. The runtime data of the application server can be view locally at the browser on via http://localhost:35000 or via the Java Profiler.

ii. On the Diagnostic Server, use http://localhost:2600 to view the running probes, configuration as well as the statistics collected from the instrumented probes connected to the server.

If the proper port is opened (35000 and 2006), you will be able to view the statistics from other machines. As such, this comes to my the end of the Diagnostics overview. Hope you have a better understanding of how Diagnostics works and the limitations with it. I will be walking through the implementation in future posts.

With SiteScope, you are able to receive the real-time information from the components in your infrastructure and stay abreast of any performance issues or bottlenecks with alerts and reports. For more information with regards to the sales talk (as usual), you can refer to the official vendor. What’s beneficial about SiteScope? SiteScope utilizies agentless monitoring technology that is similar to LoadRunner (refer to “How does the monitoring work in LoadRunner?” for information on LoadRunner monitoring mechanism) which eliminates the need for installation of (intrusive) agents on the system being monitored. What it does is to query native monitors on the infrastructure components for performance data and consolidate the information on the central SiteScope server.

One other key feature that SiteScope has to offer is the used of group templates. It allows standardization of monitoring the organization and speeding the monitoring deployment through groups and alerts. Also, not to mentioned that SiteScope is fully integrated with other HP solutions such as, HP Business Availability Center (BAC), HP Managed Software Solutions, and HP LoadRunner which allows added capabilities in monitoring for different product range. SiteScope is licensed based on point system instead of the number of servers you are installed SiteScope. A given point is been deducted based on the number of metric (monitors) you deployed. E.g. If you are monitoring CPU Utilization and Database which cost 1 point each. And you have purchased a 100 points license, the remainder of the available points will be 98 points which you can deploy for other monitorings. When you do not wish to use the monitor the CPU Utilization and Database anymore, the points are being released and you will have the initial 100 points. For more information on the licensing, we highly recommend you to go through the article, “Document ID 50972 – Licensing features of SiteScope” from the support site. Note: A metric is a system resource value, performance parameter, URL, or similar system response.

How does it work is fairly simple (avoiding the technical complexity this tool can posed). Scripts are generated using protocol-level capturing tool (Vugen). This scripts, also known as Vusers, are placed in a Scenario in the Controller and are generated to emulate the real users accessing the application. While load testing, monitoring data is collected from the servers or SUT (System Under Test) and are collected at the end of the test. This data, is then been analyzed for bottlenecks and behavior to determine the next course of action (depending on the objective of the load test, i.e. benchmarking, SLA, stress testing, etc.) such as tuning, scaling, or defining a new SLA, etc.

If you like to know more about the product from a vendor perspective, explore the HP Software here.

LoadRunner has a couple of components that makes up the whole product, namely, the Vugen, Controller, Load Generator and Analysis. It does integrate with Diagnostics and SiteScope which are separate products by itself although it comes along with every LoadRunner CD in a reduced version. The two mentioned would deserve more description than it will have here.The concept behind LoadRunner is fairly simple (or similar across load testing products), it is to generate load based on a described business process, emulated users in the form of ANSI C scripts. The components described earlier on, facilitates the load testing in the following manner. Vugen generates scripts that emulate the real users through recording a described business process that real users would perform. The recording is somewhere like a network sniffer on the protocol level and will create a basic script that describes the user actions. From here, modifications can be made to the scripts such as runtime settings, parameterization and correlation, and not limited to the two mentioned.  Once the scripts (also known as Vusers) are ready, a scenario is created in the Controller. The scenario defines the number of Vusers (scripts) to generate, the duration of the scenario, the behavior of the Vusers in terms of accessing the application (but not limited to this), and the resources (servers) that the tester would like to monitor. It also defines the Load Generators to use and any additional components such as IP Spoofing or Diagnostics module. When the scenario is done, all the tester needs to do is to run the scenario and wait for the results to be collected at the end of the test. More information on how the monitors in LoadRunner work can be found in “How does the monitoring work in LoadRunner?”

When the scenario is started, the scripts are sent by the Controller to the Load Generator and the Load Generator will generate the defined assigned amount of load to the SUT. As the name implies, Load Generator generates load and Controller controls the scenario execution. Throughout the load test, data is been consistently collected, such as running users, throughput, system resources and can be configured to receive more than those described here.

When the load test completes, the load generators will send back the data collected and stored in a results folder in the Controller. This data is then being used by Analysis to perform analyzing work. Analysis is a powerful graphical tool to look at correlations between load and system resource performance (and many more depending on what you are entitled to monitor). However, take note that having a powerful tool does not give the tester wings to fly. The tester will still need the relevant experiences and knowledge to determine bottlenecks in the system. (Usually companies charge this as consultancy).

If you like to have details of the LoadRunner architecture, you can explore the site by Wilsonmar for such information while I try to simplify it for the convenience of the beginners.