What happens when the scenario is executed?
Posted: April 21st, 2008 | Author: TnT Admin | Filed under: Concepts | Tags: LoadRunner, Scenario | 6 Comments »Here, we’ll discuss the basic overview of LoadRunner when the scenario starts execution, during and till the end. Prior to the scenario execution, the Load Generators, amount of Vusers, designated monitoring machine, ramp up timing, so on so forth should be already defined, and we will skip the discussion for it.
When the scenario starts executing, the Controller dispatches the Vusers (scripts) to the Load Generators for execution. The Vusers are then executed on the Load Generator in memory with the pre-defined amount on behalf of the Controller. These vusers in terms generate the network traffic towards the application.The data generated by the Load Generator prior Collation process (discussed later) is stored in its default temp directory. The temp directory of the Controller and Load Generator serves different purposes. For the Controller, it stores the entire result data of the scenario execution whereas, the Load Generator stores the data of its own during the scenario execution. This can be configured before the execution under the Load Generator setup if required.
Note that if your load test stretches a (1) long duration, (2) contain additional logs or (3) you foresee a large amount of data to be generated, it is advisable to ensure that you have sufficient space for the temp directory in the Load Generator. It also applies to the Controller temp directory. Either increase the disk size for the temp folder or direct it to a folder that has a larger space.
During the execution, the real time data of the monitored servers are logged as event files in the Load Generators, at the same time, they are displayed in the graphs. At the end of the test, they are collated (in the later section) to be combine as a single result directory.
When the scenario completes, either (1) the Vusers finished execution, (2) you pressed the “Stop” button or (3) the duration of the load test have reached, the Vusers will gradually exit the scenario. Once all Vusers totally exited, the Controller goes into a Collation process.
In the Collation process, data regarding the execution (event files) that are stored in the temp directory of the Load Generator, are been sent back to the Controller to be compiled to one single result data. This is stored in the default folder of the temp directory in Controller, usually in C:\Documents and Settings with the folder name res. The actual file that describes the result is stored as .lrr file extension. With this file, you can launch Analysis to perform analyzing work of the load test.
To illustrate the scenario execution briefly, you can refer to the following diagram (simplified). Click on illustration to enlarge it.
1. The scenario is started from Controller.
2. Scripts are sent from the Controller to the Load Generators for execution.
3. Scripts are executed on the Load Generator in memory.
4. Network traffic from the scripts (vuser) are generated and sent to the application.
5. While the load test is been executed, transaction timing, monitoring data and information regarding the load test are being created as event files and stored in the temp directory of the Load Generator.
6. When the scenario completes, the event files of each Load Generators are being sent back to the Controller in the Collation process to compile as a single result directory in the Controller.
This is a great site! I’ve just begun using LoadRunner, and this site is a great reference for me! I’d like to ask about setting up load generators. When testing a client server application, do we need to have the client installed on the load generator, or on the controller? Or since you’re basically replaying network traffic from the load generator to the server, is it ok to leave out the client from the load generator machine?
That depends on the type of client you are using. For example, if you are using Java clients, then the LG should have the same version of JVM and JDK installed.
Hi, what should i do if i want to send unique data (from parameterized data) to each vuser. thanks Nesh
Hi Nesh,
I believed that you’ve figure out the problem. Refer to previous comments. Have you reference the Vuser Guide on setting the unique values in Parameter List? Regards
I was running a test for 2 hours using loadrunner 8.1 after the test was done, the collation was only able to get the event files from on of the two load generators that i am using. any idea on why does that happen? is there is a way for me to still get the results or the event files from the generator? any advice is appreciated Thanks
Hi Nesh,
You can refer to the link below that talks about how to manually retrieve the results back from the Load Generators.
Manual collation of result set data
You will have to have a valid login to the support website. Hope that helps.