Testing Interview Questions

1. What is the differences 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 shows the current graphs value and 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 Y axis becomes X axis of merged graph. Y axis of the graph that was merged becomes merged graphs Y axis.

2. How did you planned 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 two 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 of usage are decided from this diagram. transaction profile gives us the information about the transaction names and their priorities levels with regard to the scenario we are deciding.

3. What does Vuser_init action contains?
Vuser_init action contains procedures to login to a server

4. What does Vuser_end action contain?
It contains logoff procedures.

5. What is think time? How does you change the threshold?
Think time is the time that a real user waits between actions. Ex: When a user receives data from a server, the user may wait serveral seconds to review the data before resposding. 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 5 seconds. We can change the think time threshold in the recording options of the VuGen.

6.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 out put log.This is mainly used during debugging when we want information abut parameter substitution, Data returned by the server, advanced trace.

7. Explain the following functions
lr_debug_message - the lr_debug_message function sends a debug message to the out put log when the specified message class is set.
lr_output_message - this function sends notification to the controker output window and the Vuser log file.
lr_error_message - this function sends an error message ti the load runner output window.
lrd_stmt- this function associates a character string ( usually a sql statement) with a courser.
this function sets a sql statement to be processed.
lrd_fetch - this function fetches th next row from the result set.
Throughput- if the thruoghput scales upword as time progresses and number of Vusers incraesed, this indecates 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.

Types of goals in goal oriented scenario

Load runner provides u with 5 different types of goals in goal oriented scenario:
The no. of concurrent Vusers
The no. of hits per second
The no. of transactions per second
The no. of pages per minute
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 no. 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 56 Vusers, there is a sudden, sharp increases 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 56 Vusers running simultaneously.

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