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 which 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. 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.

 

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 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 is think time? How do you change the threshold?

Think time is the time that a real user waits between actions. 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 which 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.

 

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.