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What is correlation? How we will do that in Load runner?

Asked by: Interview Candidate | Asked on: Dec 27th, 2006
Showing Answers 1 - 8 of 8 Answers
Naresh

Answered On : Dec 28th, 2006

Hi all,

It is the process in Loadrunner to handle dynamic values. It is equvalent to Output value concept in QTP.

Here the dynamic value is replaced by a variable. Now each time you the script, the dynamic value in the application is assigined to the variable & it in turn passes to the required object in the application.

Regards

Naresh J

  
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Anandha Kumar

Answered On : Jan 1st, 2007

View all answers by Anandha Kumar

hi Correlation is used to capture dynamic values in performance testing.Suppose the values like time and date at same of recording never be same as run time and some times or some times when working with web applications "session ids". What we have to do is We have to use some functions whose o/p works as i/p of some other function and finally we get the value of dynamic variable which can have the value as o/p these functions. tese o/p value will exactly mathces with run time value of dynamic varibles and test never fails due to dynamically changing variables.This correlation can be done in 2 ways.first when u r not femiliar with cata items whome u have to correlate then u can use lr's search correlation option, lr list all dynamically changing variables of ur test and lists then u can choose accrding to ur requirement. it's called as Auto correlationSecondly if u r femiliar with those whom u have to correlate direcxtly u can correlate it's called as Manual correlation

  
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kishoreqc

Answered On : Jan 30th, 2007

hi,correlation is using for identifying and resolving the unique values in the application.

  
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nsarathc

Answered On : Mar 9th, 2007

View all answers by nsarathc

Correlated data is data which is sent to the Client from the Server, and later sent back to the Server by the Client.

Correlation is where the script is modified so that some of the hard coded values in the script are no longer hard coded. Rather then sending the original value to the server, we may need to send different values.
 
For example, the original recorded script may have included the server sending the client a session identification number, something to identify the client during that particular session. This Session ID was hard coded into the script during recording.
 
During replay, the server will send the client a new Session ID. You need to capture this value, and incorporate it into the script so you can send it back to the server to correctly identify yourself for this new session. If you leave the script unmodified, you will send the old hard coded Session ID to the server. The server will look at it and think it invalid, or unknown, and so will not send the pages that have been requested. Replaying script with old will Session ID not have successfully fooled the server into believing it is a client.
 
Correlation is the capturing of dynamic values passed from the server to the client and back. You save this captured value into a parameter, and then use this parameter in the script in place of the original value. During replay, the replay engine will now listen to what the server sends to it, and when it makes requests of the server, send this new, valid value back to the server; thus fooling the server into believing it is talking to a real client.

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purnaprasad

Answered On : Jun 26th, 2008

View all answers by purnaprasad

Data correlation is the process of extracting data that is returned from a server, and then sending it back to the server in a subsequent request. There are two main parts to data correlation. One part occurs during test generation and script editing, and the other part occurs during script execution. The test generation part of data correlation is the most significant part. There is automatic data correlation that is performed during test generation, and there is manual correlation that can be performed during script editing. There are several different things that can be done as part of manual correlation: you can substitute values into a site from a data pool, a built-in data source, or a reference that is already created.

  
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Correlation is where the script is modified so that some of the hard-coded
values in the script are no longer hard-coded. Rather then sending the original
value to the server, we may need to send different values.


Correlation is the capturing of dynamic values passed from the server to the
client and back. You save this captured value into a parameter, and then use
this parameter in the script in place of the original value.


During replay, the replay engine will now listen to what the server sends to
it, and when it makes requests of the server, send this new, valid value back to
the server; thus fooling the server into believing it is talking to a real
client

  
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vcdgmail

Answered On : Jul 28th, 2009

View all answers by vcdgmail

Correlation is a used to obtain data which are Unique for each run of the scriptsand which are generated. Correlation provides the value to avoid errors arising due to duplication values. So we can create rules and get rid of duplication errors

  
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sindhu kumari

Answered On : Mar 11th, 2014

Data Correlation is nothing but dynamic handling data we can say it simply.That means we have to find the data which are generated by the server and we need to change that value with a variable in Load Runner.Then after we need to place the variable instead of correlated value.It is the process of Manual correlation.we can also do

Automatic Correlation in Load Runner in two ways.

1.Scan script for Correlation
2.Correlation Rule


if we want to do first method then we need to record test first then we need to select scan script for correlation option in Tools menu.It shows one window with correlated values.select simply and click on correlate.It automatically displays correlation function in script.If we want we can change the variable also.


if we want to do Correlation rule before recording script we need to give some rules like left boundary ,right boundary values and other things.After that we need to record the script it automatically correlates the value.But all the times this Automatic Correlation doesn't work in Load Runner.

In Load Runner, we will use web_reg_save_param() function to do Manual Correlation with some parameters like variable name,left boundary,right boundary,ordinal value etc.,

  
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