Load Testing is performed to find out if the system can handle the expected load upon deployment under real-world conditions.
Load testing is to test that if the application works fine with the loads that result from large number of simultaneous users, transactions and to determine weather it can handle peak usage periods.
What is Stress testing?
Stress testing is performed to find the application’s breaking point.
What is Performance testing?
To determine whether system transactions are being performed in an acceptable timeframe. This should be done standalone and then in a multi user environment to determine the effect of multiple transactions on the timing of a single transaction.
What is Volume/Endurance testing?
Volume/Endurance testing is performed to find the stability of the system with respect to handling large amounts of data over extended time period.
What is LoadRunner?
LoadRunner is a mercury interactive tool that tests the performance of an application.
LoadRunner enables you to test your system under controlled and peak load conditions.
LoadRunner stresses your application to isolate and identify potential client, network, and server bottlenecks.
When LoadRunner is used?
As we all know that functionality testing helps ensuring that the product/application works fine according to the requirments and the client verifications are validated. This is always done by single user and depending upon the complexity of the application or the product. Many test cases are written to ensure that the components functions as intended, but when the application passes this TollGate of functional testing, there is always question of what will happen to the application/product when multiple users are accessing them. Here comes the load testing which ensures that the application performs without breakdown for the required users as indicated in the CS ( customer specification ) document. For this we need to ensure proper loadtesting is done using automation, as we all know we cannot ask 50 real users sitting by a computer and click is done, moreover all the areas of concerned will not be covered. One such loadtesting-automated tool is loadrunner that is used to emulate the behaviour of real time user. Here the loadrunner is used, there are other load testing tools in the market but Mercury stand in forefront.
What are the advantages of using LoadRunner?
The LoadRunner advantages are:
1. Loadrunner reduces the personnel requirement by replacing the humun users with the Vusers(virtual users).
2. Numarous Vusers can run on a single computer,so Loadrunner reduces the hardware requirements.
3. It allows you to effectively control all Vusers from single point of control
4. Loadrunner automatically records the performance of the client/server during test.
5. Loadrunner checks where performance delays occur network/client delays.
6. Loadrunner monitor the network and server resource to help the improve performance.
When do you do load and performance Testing?
We perform load testing once we are done with interface (GUI) testing. Modern system architectures are large and complex. Whereas single user testing primarily on functionality and user interface of a system component, application testing focuses on performance and reliability of an entire system.
For example, a typical application-testing scenario might depict 1000 users logging in simultaneously to a system. This gives rise to issues such as what is the response time of the system, does it crash, will it go with different software applications and platforms, can it hold so many hundreds and thousands of users, etc. This is when we set do load and performance testing.
What are the components of LoadRunner?
The components of LoadRunner are:
i) Virtual User Generator
ii) Load Generator
iiii) Controller and the Agent process
iv) LoadRunner Analysis and Monitoring.
What is controller?
A controller is like an administrator who creates, maintains, and executes designed Scenarios; also run and stop the load test.
What’s load generator?
Load generator is computers that run the Vusers.
What’s analysis?
Analysis processes the gathered scenario results and generates graphs and reports.
How many controllers must be installed in order to conduct a load test?
Only one controller is needed.
What factors determines the location of load generators?
Your customer locations determine where to install your load generators.
What Component of LoadRunner would you use to record a Script?
The Virtual User Generator (VuGen) component is used to record a script. It enables you to develop Vuser scripts for a variety of application types and communication protocols.
What Component of LoadRunner would you use to generate Vusers?
Load Generator
What Component of LoadRunner would you use to playback the script in multi user mode?
The Controller component is used to playback the script in multi-user mode. This is done during a scenario run where a Vuser script is executed by a number of Vusers in a group.
Did you use LoadRunner? What version? - Yes. Version 8.0
What is the LoadRunner testing process?
There are 7 steps.1-Planning the test.2-Creating the Vuser script.3-Creating the scenario.4-Running the scenario.
5-Monitor the Scenario6-Analysis the test result.
7. Create the desired form of report.
Explain the Load testing process.
Step 1: Planning the test.
Here, we develop a clearly defined test plan to ensure the test scenarios we develop will accomplish load-testing objectives.
Step 2: Creating Vusers.
Here, we create Vuser scripts that contain tasks performed by each Vuser, tasks performed by Vusers as a whole, and tasks measured as transactions.
Step 3: Creating the scenario.
A scenario describes the events that occur during a testing session. It includes a list of machines, scripts, and Vusers that run during the scenario. We create scenarios using LoadRunner Controller. We can create manual scenarios as well as goal-oriented scenarios. In manual scenarios, we define the number of Vusers, the load generator machines, and percentage of Vusers to be assigned to each script. For web tests, we may create a goal-oriented scenario where we define the goal that our test has to achieve. LoadRunner automatically builds a scenario for us.
Step 4: Running the scenario.
We emulate load on the server by instructing multiple Vusers to perform tasks simultaneously. Before the testing, we set the scenario configuration and scheduling. We can run the entire scenario, Vuser groups, or individual Vusers.
Step 5: Monitoring the scenario.
We monitor scenario execution using the LoadRunner online runtime, transaction, system resource, Web resource, Web server resource, Web application server resource, database server resource, network delay, streaming media resource, firewall server resource, ERP server resource, and Java performance monitors.
Step 6: Analyzing test results.
During scenario execution, LoadRunner records the performance of the application under different loads. We use LoadRunner’s graphs and reports to analyze the application’s performance.
Step 7: Create the desired form of report.
What is planning for the test?
Define the performance testing requirements for example no. of concurrent users, typical business processes and required response time.
Mainly in LoadRunner we plan how many Vuser are to be created and on which machine we are going to be worked. These are mainly based on two things: 1. Task distribution, 2. Transaction profile.
How did you plan the Load? What are the Criteria?
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.
What is task distribution diagram?
This diagram helps us to find the peak time. It gives us the information on number of users for a particular transaction and the time of the load.
Which business process should you record?
Mission-critical are the transactions that any business depends on the most.
Heavy throughput is the transactions that are used most often.
Dynamic Content is the transactions that require the database lookup, dynamic page or text generation during the process.
What’s a Vuser?
Vuser is Virtual user that is generated virtually to emulate the steps of real human users.
What are the Vuser types?
All Protocols: A list of all supported protocols in alphabetical order.
Application Deployment Solution: For Citrix
Client/Server: For DB2, SQL…
Custom: For C, VB, Java Templates
Distributed Components: For COM/DCOM, Cobra-Java
E-business: Web (HTTP/HTML)
Enterprise Java Bean: For EJB Testing
Legacy: For Remote Terminal Emulation (RTE)
Mailing Services: Internet Messaging (IMAP), MS Exchange (MAPI), POP3 and SMTP.
Middleware: Jacada and Tuxedo
Streaming: For Media Player
Wireless: For I-Mode, VoiceXML and WAP
How many types of Vuser are available?
There are several type of Vuser(GUI ,Database ,RTE(terminal emulator), SAP, DCOME, People soft, java, Baan)
What is the difference between script view and tree view?
Tree view shows us our recording in icon-based format, whereas script view shows us coding like C, VB languages.
What is VuGen?
It is a LoadRunner Vuser script generator (use for recording the data base Vuser script)
VuGen is a loadrunner component used to generate Vuser script i.e. here we record a business operation performed by a single user.
Vugen-Virtual user generator is used to generate scripts for all non-GUI Vusers.
The Vugen records the behavior of the client s/w, and automatically generates a script that can be used by the controller to run Vusers.
How many section Vuser scripts have?
Vuser script contains 3 sections:
Vuser_init: contains the login statements of the script
vuser_action: contains acton statements performed by Vuser
Vuser_end: contains log off statements
What does Vuser_init action contain?
Vuser_init action contains procedures to login to a server.
What does Vuser_end action contain?
Vuser_end section contains log off procedures.
What do you mean by creating Vuser script?
Creating Vuser script for emulate the action that virtual user Perform during the scenario execution.
Capturing the end-user activities into automated scripts.
Explain the recording mode for web Vuser script.
We use VuGen to develop a Vuser script by recording a user performing typical business processes on a client application. VuGen creates the script by recording the activity between the client and the server. For example, in web-based applications, VuGen monitors the client end of the database and traces all the requests sent to, and received from, the database server. We use VuGen to: Monitor the communication between the application and the server; Generate the required function calls; and Insert the generated function calls into a Vuser script.
What is the process for developing a Vuser script?
There are 5 steps for developing a Vuser script.1-Recording the Vuser script .2-Edit the Vuser script.3-Runtime setting .4-Run the Vuser script in stand-alone mode.5-Incorporate the Vuser script into a LoadRunner scenario.
How you enhance the basic script?
By adding control-flow, structure, by inserting transaction point and rendezvous point, adding functions
The important steps needs to carried to enhance a basic script
1. Parameterization (Providing the user inputs to the application)
2. Correlation (handling dynamic server responses)
3. Transaction names (to get the response time)
4. Think time (to simulate the real time user wait time)
5. Text check (validating the server response pages for the request).
What is GUI Vuser and on which platform it will run?
GUI Vuser operate graphical user interface application and it can run in either the MS-Windows / X-Windows environment.
GUI Vusers actually perform the actions using the client.this means that fewer GUI Vusers can be run per workstation than the other types of Vusers due to the overload of the client, and is infact limited to one GUI v user per workstation. GUI Vusers are not so much to generate load on a system but to test end -to end performance associated with various business processes.
What is LoadRunner API function?
Data base Vuser do not operate client application. Using LoadRunner API function the database Vuser can access the data from the server.
How you develop the database Vuser script ?
DB Vuser performs operations against a database server.
Recording a DB Vuser is as simple as performing a business process while having launched the LR Vugen.
This creates a script that is used by LR to perform the recorded business process. Once recorded, a script is then parameterized. This process involves replacing hard coded data values in the script with parameters that refers to tables external to the script.
Values can then be placed in these tables allowing Vusers to perform a single business process, but with different data each time.
When do you disable log in Virtual User Generator, When do you choose standard and extended logs?
Once we debug our script and verify that it is functional, we can enable logging for errors only. When we add a script to a scenario, logging is automatically disabled.
Standard Log Option: When you select Standard log, it creates a standard log of functions and messages sent during script execution to use for debugging. Disable this option for large load testing scenarios. When you copy a script to a scenario, logging is automatically disabled.
Extended Log Option: Select extended log to create an extended log, including warnings and other messages. Disable this option for large load testing scenarios. When you copy a script to a scenario, logging is automatically disabled. We can specify which additional information should be added to the extended log using the Extended log options.
How do you debug a LoadRunner script?
VuGen contains two options to help debug Vuser scripts-the Run Step by Step command and breakpoints. The Debug settings in the Options dialog box allow us to determine the extent of the trace to be performed during scenario execution. The debug information is written to the Output window. We can manually set the message class within your script using the lr_set_debug_message function. This is useful if we want to receive debug information about a small section of the script only.
How do you write user defined functions in LR? Give me few functions you wrote in your previous project?
Before we create the User Defined functions we need to create the external library (DLL) with the function. We add this library to VuGen bin directory. Once the library is added then we assign user defined function as a parameter. The function should have the following format: __declspec (dllexport) char*
Examples of user defined functions are as follows:GetVersion, GetCurrentTime, GetPltform are some of the user defined functions used in my earlier project.
Explain the following functions:
lr_debug_message - The lr_debug_message function sends a debug message to the output log when the specified message class is set.
lr_output_message - The lr_output_message function sends notifications to the Controller Output window and the Vuser log file.
lr_error_message - The lr_error_message function sends an error message to the LoadRunner Output window.
lrd_stmt - The lrd_stmt function associates a character string (usually a SQL statement) with a cursor. This function sets a SQL statement to be processed.
lrd_fetch - The lrd_fetch function fetches the next row from the result set.
What are the general runtime settings?
Run Logic, Pacing, Log, Think Time, Miscellaneous.
What’s run Logic?
The number of iterations need to run the script.
What’s pacing?
The time between two iterations while running the script.
What is log?
Notes and comments acquired by the LR by default of any error or ever the entire process.
How do you configure log?
You can select either Standard or Extended Log; also you can manually program a Vuser script to send the information by using the Lr_error_message and Lr_output_message functions.
How do you do error handling?
By default, when Vuser detects error, it stops executing; however, using runtime settings one can enable the “Continue on error” so that execution does not stop on error.
Difference between run Vuser as process and thread.
Running Vuser as a process (parent) requires more memory space because it uses one driver for each Vusers whereas thread (child) uses only one driver for all Vusers.
Why would you want to check the run Vuser as a thread option?
This will save memory space.
What is run-time-setting?
Run time setting means specifying the way the Vuser script runs.
To set the pacing, think time, iteration, proxy settings, authentication and correlation.
What are the changes you can make in run-time settings?
The Run Time Settings that we make are:
Pacing - It has iteration count.
Log - Under this we have Disable Logging Standard Log and
Extended Think Time - In think time we have two options like Ignore think time and Replay think time.
General - Under general tab we can set the Vusers as process or as multithreading and whether each step as a transaction.
What is think time? How do you change the threshold?
Think time is the time that a real user waits between actions.
The time a real user takes between steps.
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 that 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.
What is the difference between standard log and extended log?
The standard log sends a subset of functions and messages sent during script execution to a log. The subset depends on the Vuser type Extended log 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.
Where do you set Iteration for Vuser testing?
We set Iterations in the Run Time Settings of the VuGen. The navigation for this is Run time settings, Pacing tab, set number of iterations.
How do you encrypt text in LR?
In the script view we first select the text to encrypt and right click on it to select the Encrypt String from the menu.
How do you perform functional testing under load?
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.
What is the advantage of running the Vuser as thread?
VuGen provides the facility to use multithreading. 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.
If you want to stop the execution of your script on error, how do you do that?
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.
What is stand-alone mode?
To verify that the script runs correctly.
Running the script without using controller.
Example: Desktop applications are stand-alone mode. Java applications.
We will also have Web Based. Example: Internet. . Net applications.
What types of function generate and insert by the vugen to the script when you record a script?
1-LR Function.(Vuser function)
2- protocol function.
What is LR-function?
Obtain the information about Vuser running in a scenario.
It is a general function that is accessed by all types of users.
This is also called LR function because all general functions start with lr.
What is protocol function?
Obtain the information about the type of Vuser.
What is the Vuser in the scenario?
The Vuser is virtual users nothing but those who simulate the real users.
The virtual users who take the place of real users operating client software, such as IE sending requests using the HTTP protocol to IIS or Apache web servers.
The Vuser is the real time user who actually performs some actions on that particular scenario simulated by the loadrunner.
What is transaction?
We define transaction to measure the system performance. It measures the time it takes for the server to perform the task submitted by the client.
An action performed by the user, execution of an online application Examples: Login is a transaction, check email is another transaction, browse for particular product category is another transaction. Purchase something online is another transaction!
A transaction represents an action or a set of actions that one would want to measure the performance of the server with.
What is the LoadRunner start-transaction and its syntax?
It will start the transaction on the script.
Syntax. Lr_start_transaction ("transaction name").
What is the LoadRunner end transaction and its syntax?
It will end the transaction.
Syntax. Lr_end_transaction("transaction name", LR-AUTO).
What is a checkpoint?
It verifies whether a visual cue appeared as expected.
How many checkpoints are there in LR?
There are two checkpoints in LR, Text checkpoint and Visual Cue/Image Checkpoints.
What is a rendezvous point?
You insert rendezvous points into Vuser scripts to emulate heavy user load on the server. Rendezvous points instruct Vusers to wait during test execution for multiple Vusers to arrive at a certain point, in order that they may simultaneously perform a task.
For example, to emulate peak load on the bank server, you can insert a rendezvous point instructing 100 Vusers to deposit cash into their accounts at the same time.
Rendezvous point instruct Vusers to wait during test execution for multiple Vusers to arrive at a certain point, in order that they may simultaneously perform a task.
v users execute the script whenever they get the time slot. In this process some Vusers may reach end of the script while other Vusers may not have yet started. So to stop the execution of Vusers untill all the Vusers reach at a particular point and execute all at a time we insert rendezvous point.
Rendezvous point means multiple user start the application simultaneously at particular time.
Rendezvous point is a work place where all users gathered and released at a time to perform their task on the application. This is used to increase load on the application, to observe how application is working (to measure performance) at peak stages, and to know bottleneck point.
Rendezvous point is Synchronization point that helps us to synchronize all the Vusers and stops them at that point before executing the subsequent transactions. The significance of this is to emulate some heavy load only to particular portion of the scenario and experience the behavior of the application.
Rendezvous point is a point where all or users are stopped at one point and all the users are released at a time so as to obtain concurrency.
It’s a meeting point between a given numbers of Vuser to measure the performance of the server when those Vusers are allowed to start one specific transaction at the same time.
When the rendezvous point is inserted?
The "Rendezvous point” could be inserted at the moment, when exactly you wanted the Vusers to act simultaneously.
For Example,
You can find a start and end Transaction, in the script if you have generated.
Insert the rendezvous point, just before starting the transaction.
This implies that, all the Vusers are asked come and reach at the point before starting the transaction, and perform the operation at that particular time.
Where you insert the rendezvous point?
Rendezvous point insert in to the script to calculate the peak load of the server. Syntax. lr-rendezvous("rendezvous name").
Why we insert the rendezvous point while running?
It is an interrupt point to stop current Vuser script execution untill remaining Vusers scripts also executed upto that point.It maintains ' Load Balancing ' while running Vusers script.
What is rendezvous graph?
It indicates when Vuser were released from rendezvous point and how many Vuser are released from each point. It helps the transaction performance time.
When does the controller release the rendezvous?
The controller releases the Vusers from the rendezvous either when the required number of Vusers arrives, or when a specified amount of time has passed.
Can you insert rendezvous point after recording?
You can insert in your script after you complete a recording session.
How do you insert rendezvous point?
Click Insert>Rendezvous for the VuGen menu.
Where do you insert rendezvous point?
It is done in the script.
How do you set the rendezvous attributes?
We can set the following rendezvous attributes from the Rendezvous information dialog box (Scenario>Rendezvous).
What is Host?
Host is machines that execute the Vuser script.
Host is the System, Generally known as Controller to execute the Vuser Script. Either it can be Local host or Remote Host.
What is a parameter and parameterization?
Parameter is a placeholder that replaces a recorded value using an external data source.
Parameterization replaces the recorded value with a placeholder to allow us to use the same script with multiple sets of data.
Why do you parameterize the Vuser script?
Unique Constraint: To accommodate any field that requires a unique value for each user.
Date Constraint: It helps in the case when a script is recorded yesterday and run or execute today will give us an error.
Data Dependency: When one data value of an object determines what the acceptable value can be for another object.
Data Caching: It eliminates the effects of data caching which creates misleading results.
What are the parameter types?
Internal Data, Data Files, and User-defined Functions.
What is the data access method?
It tells the LR in what order to use data from the file (data source): Sequential, Random, Unique, Same line as
What changes do you need to make to view the parameter data in execution log?
To see parameter data in the execution log, select Extended log and Parameter substitution in the Run-time settings.
After parameterize the script, what are the most important run time settings do you need to change?
The number of iterations should equal the number of rows in the data file in run logic section of Run-time settings.
Explain the difference between the script run time setting and controller runtime settings?
The difference is that the VuGen script run time setting only works with itself, but when it is sent to the controller, it can override the settings.
Why do you create parameters?
Parameters are like script variables. They are used to vary input to the server and to emulate real users. Different sets of data are sent to the server each time the script is run. Better simulate the usage model for more accurate testing from the Controller; one script can emulate many different users on the system.
What is correlation? Explain the difference between automatic correlation and manual correlation.
Correlation is used to obtain data which are unique for each run of the script and which are generated by nested queries. Correlation provides the value to avoid errors arising out of duplicate values and also optimizing the code (to avoid nested queries). Automatic correlation is where we set some rules for correlation. It can be application server specific. Here values are replaced by data which are created by these rules. In manual correlation, the value we want to correlate is scanned and create correlation is used to correlate.
How do you find out where correlation is required? Give few examples from your projects?
Two ways: First we can scan for correlations, and see the list of values that can be correlated. From this we can pick a value to be correlated. Secondly, we can record two scripts and compare them. We can look up the difference file to see for the values that needed to be correlated. In my project, there was a unique id developed for each customer, it was nothing but Insurance Number, it was generated automatically and it was sequential and this value was unique. I had to correlate this value, in order to avoid errors while running my script. I did using scan for correlation.
Where do you set automatic correlation options?
Automatic correlation from web point of view can be set in recording options and correlation tab. Here we can enable correlation for the entire script and choose either issue online messages or offline actions, where we can define rules for that correlation. Automatic correlation for database can be done using show output window and scan for correlation and picking the correlate query tab and choose which query value we want to correlate. If we know the specific value to be correlated, we just do create correlation for the value and specify how the value to be created.
What is a function to capture dynamic values in the web Vuser script?
Web_reg_save_param function saves dynamic data information to a parameter.
What is a scenario?
A scenario defines the events that occur during each testing session. For example, a scenario defines and controls the number of users to emulate, the actions to be performed, and the machines on which the virtual users run their emulations.
A scenario is a file that defines which Vusers to execute, the number of Vusers to run, the goals of the test, which computer hosts the Vusers and the conditions under which to run the load test.
How to create a scenario?
We have to install LoadRunner controller to the host. Then we include list of host (where Vuser script execute) then list of Vuser script (where Vuser run) and then list of Vuser that run during the scenario.
What do you mean by Remote Command Launcher (RCL)?
Rcl enables the controller to start the application on the Host machine.
RCL is whatever local request can be converted into remote request
Remote Command Launcher is used to start the application from the Host. Host is a Computer or Machine
What’s the difference between manual and goal oriented scenarios?
In Manual you create the scenarios yourself by defining the number of Vuser groups building a schedule, the total number of Vusers to be used and assigning a percentage of the total number of Vusers to each script.
In Goal oriented LR manages Vusers automatically.
How many goal types are there in goal-oriented scenarios?
There are five types: The number of Vusers, the number of hits per second, the number of transactions per second, the number of pages per minute, and the transaction response time you want your scenario to reach.
What’s ramp up and ramp down?
Ramp up is the incremental points and Ramp down is the detrimental points from the Ramp up point.
What is Ramp up? How do you set this?
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’
What’s the difference between using schedule by scenarios and schedule by group?
Schedule by Scenario allows us to see how the application is performing under typical and peak hours. And Schedule by Group allows us to see how the application is performing when certain business process is being used.
Why is initialization important?
It helps in reducing the CPU consumption and getting realistic results.
Where will you set Vuser quotas?
In the runtime settings from the Tools>Options.
What happens when running scenarios?
During runtime results are stored locally on each load generator. After execution, results from all load generators are transferred to the controller’s results directory for analysis.
What is the relation between Response Time and Throughput?
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.
Explain the Configuration of your systems.
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.
How do you identify the performance bottlenecks?
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 that causes increased response time. The measurements made are usually performance response time, throughput, hits/sec, network delay graphs, etc.
If web server, database and Network are all fine where could be the problem?
The problem could be in the system itself or in the application server or in the code written for the application.
How did you find web server related issues?
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.
How did you find database related issues?
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.
What is the difference between Overlay graph and Correlate graph?
Overlay Graph: It overlay the content of two graphs that shares a common x-axis. Left Y-axis on the merged graph show’s the current graph’s value & Right Y-axis show the value of Y-axis of the graph that was merged.
It overlay the content of two graphs that shares a common x-axis.
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.
Plots the Y-axis of two graphs against each other.
What is Throughput?
If the throughput scales upward as time progresses and the number of Vusers increase, this indicates that the bandwidth is sufficient.
If the graph were to remain relatively flat as the number of Vusers increased, it would be reasonable to conclude that the bandwidth is constraining the volume of data delivered.
Write types of Goals in Goal-Oriented Scenario.
Load Runner provides you with five different types of goals in a goal oriented scenario:
i) The number of concurrent Vusers
ii) The number of hits per second.
iii) The number of transactions per second.
iv) The number of pages per minute.
v) The transaction response time that you want your scenario.
Analysis Scenario (Bottlenecks):
In Running Vuser graph correlated with the response time graph you can see that as the number of Vusers increases, the average response time of the check itinerary transaction very gradually increases. In other words, the average response time steadily increases as the load increases. At any point, there is a sudden, sharp increase in the average response time. We say that the test broke the server. That is the mean time before failure (MTBF). The response time clearly began to degrade when there were more than maximum Vusers running simultaneously.
What is LoadRunner Agent?
Agent is interface between host machine and controller.
LoadRunner Agent is the mediator between LoadRunner Controller and the Host.
LoadRunner agent enables the controller and the generator to communicate with each other.
How you load a LoadRunner Agent?
Controller instructs the remote command launcher to lunch the Agent.
This is auto generated while installing LoadRunner.
While running the scenario loadrunner controller instructs the remote agent dispatcher to launch loadrunner agent. The controller instructs the loadrunner agent to initialize,run,pause,stop the Vusers.
What are the elements in the LoadRunner controller?
Title bar(name of the scenario presently working).
Menu bar (selecting the various command).
Tool bar.
Status bar.
What are the 5 icons appear in the buttom of the controller windows?
1- Host windows (list of machine). 2- Script windows(list of all the Vuser script)3- Rendezvous windows. 4- Transaction windows(display all the transaction) . 5- Output window( display error and notification message).
What is .lrs?
LoadRunner save the information in a scenario files.
LoadRunner has got three main components. VUGen, Controller and Analyzer.
The extension of files in Vugen is .usr, files in Controller i.e. scenarios created will be saved with extension .lrs and in analyzer with .lra.
What is scenario wizard?
Through scenario wizard we can create a new scenario.
What is filtering and sorting?
We can filter the information display only those items that meet the selected criteria (filter box). Example, you can filter Vuser only those who are in ready state. Sorting - we can sort all the Vuser in the Vuser list. In order to their Vuser ID(1,2,3,4,5,6,7,8,9).
What are the information crating for each host?
1-The status of the host. 2-The platform type of the host(windows/unix). 3-Details of the scenario.
How to create a host list for a scenario?
1-Install remote command luncher on every machine. 2-Add the name of the host to the host lists. 3-Set attributes for each host.4-Select which hosts will take part in the scenario.
What the host attributes determine ?
1-The maximum number of Vuser that host can run.2-The initialization quota.3-The location of the win runner configuration file.4. The location of the file during run-time.
How you set maximum number of Vuser that a host can run?
We can modify the maximum number of Vuser according to the (available resource, the needs of your scenario, LoadRunner license agreements).
Initially run the application with one user. Save the results.Now increase the load to 5,15,50,100,500,1000 slowly.During the process, you will find the system will break down for a particular number of virtual users. From there start decreasing the load and u will find the bottleneck for the application so that u can call for the quality meeting.
First get the hardware configuration (RAM size) of the host.Each Vuser takes 4.2 MB(approx.) for execution. Based on this information you can decide the maximum no. of Vuser.
What do you mean by initialization of quota?
Capabilities of the host that at a time how many Vuser Are initialize.
When the LoadRunner controller open the win runner file then What is the location of the winner configuration file?
Wrun.ini.
What is scenario default?
Instruct the Vuser to use the win runner configuration file.
What is local configuration file?
Instruct the Vuser to use hosts win runner configuration file.
What do you mean by path?
Use win runner configuration file that is in a specific location on the network.
During run time where the hosts saves the files.
Temporarily in the local drive of each host.
What are the information contain by script windows for each script in the list?
1- Name of the Vuser script. 2- The type of the Vuser.3- The location(path).4- Command line option.
What is the purpose of running the scenario?
To check the response time of the client/server system under load.
When a scenario run exactly what happened?
1-The controller checks the scenario configuration information.2-then next it invoke the application that you select to run with the scenario. 3- then transform each script to its related hosts, when the Vuser are ready they start execution.
How to run a scenario?
Open an existing scenario. Configure the scenario. Set the result directory.Run the scenario.
When you initialize the Vuser what happen?
The Vuser status changes from DOWN to PENDING to INITILIZAING to READY. If Vuser fails to initialize, the Vuser status changes to ERROR.
What is pause command?
It changes the status of the Vuser from RUNNING TO PAUSE.
What is running virtual user graph?
It displays the number of the Vuser that execute Vuser script during each second of the scenario run. Only running and rendezvous state are including. (Loading, ready and pause are not displayed).
When you run the scenario, by default Virtual user graph, throughput and hits per sec graphs will be displayed. In the first one you can find out how many virtual users are running the application and the time taken by them to finish the operation.
What is report viewer?
Each report viewer contains the report header and report viewer tool bar.
What is report header and what is the information contains?
It display general scenario information and it contain the information like (title, scenario, result start time, end time and duration).
What is transaction per second graph (pass)?
It display the number of completed, successful transaction perform during each second of scenario run.
What in percentile graph?
The percentage of transaction that were performed within a given time range.
What are the Vusers statuses?
DOWN The Vuser is down.
PENDING The Vuser is ready to be initialized and is waiting for an available load generator, or is transferring files to the load generator. The Vuser will run when the conditions set in its scheduling attributes are met.
INITIALIZING The Vuser is being initialized on the remote machine.
READY The Vuser already performed the init section of the script and is ready to run.
RUNNING The Vuser is running. The Vuser script is being executed on a load generator.
RENDEZVOUS The Vuser has arrived at the rendezvous and is waiting to be released by LoadRunner.
DONE.PASSED The Vuser has finished running. The script passed.
DONE.FAILED The Vuser has finished running. The script failed.
ERROR A problem occurred with the Vuser. Check the Status field on the Vuser dialog box or the output window for a complete explanation of the error.
EXITING The Vuser has finished running or has been stopped, and is now exiting.
STOPPED The Vuser stopped when the Stop command was invoked.
What’s Time out?
It indicates that the Web server is not responding or that connectivity has slowed between the load generators and the Web servers.
What’s HTTP 500?
It indicates either that individual business processes are failing under load, or that the Web application itself has crashed.
What’s load balancing?
Load balancing evenly distributes the load generated by Vuser among the requested load generator machines, ensuring an accurate load test.
Write some monitor types?
Runtime Monitors, transaction monitors, web resource monitors, system resource monitors, network delay monitor, firewall monitor, web server resource monitors.
Write the default graphs?
i) Running Vusers
ii) Hits per Second
iii) Transaction Response time
iv) Windows resource.
What’s the benefit of windows resource monitors?
It shows the windows resources usage in real time and locates any bottleneck on a particular load generator machine.
What is relation between response time and throughput?
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.
How do you identify the performance bottleneck?
Performance bottleneck can be identified using monitors.
How did you find web server related issues?
We can use the Web resource monitors.
How did you find database related issues?
By running the Database monitor and help of Data Resource Graph.
What are the layers of OSI models?
i) Physical layer
ii) Data link layer
iii) Network layer
iv) Session layer
v) Transport layer
vi) Presentation layer
vii) Application layer
What’s firewall?
It is used to block outside communication with some exceptions.
What’s IP spoofing?
It emulates real-world network traffic and associates each Vuser with a different IP address.
What’s proxy?
A proxy server acts as an intermediary between a workstation and the Internet so that the enterprise can ensure security, administrative control and caching service.
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