What is memory leak, page fault and how they affect LoadRunner performance?


Continuing with our discussion on technical terms used in LoadRunner, we will now see the meaning of memory leak and page fault and how they affect LoadRunner performance .

What is memory leak?

A memory leak is a particular type of unintentional memory consumption by a computer program where the program fails to release memory when no longer needed. This condition is normally the result of a bug in a program that prevents it from freeing up memory that it no longer needs.This term has the potential to be confusing, since memory is not physically lost from the computer. Rather, memory is allocated to a program, and that program subsequently loses the ability to access it due to program logic flaws.

What is a page fault?

An interrupt that occurs when a program requests data that is not currently in real memory. The interrupt triggers the operating system to fetch the data from a virtual memory and load it into RAM.

An invalid page fault or page fault error occurs when the operating system cannot find the data in virtual memory. This usually happens when the virtual memory area, or the table that maps virtual addresses to real addresses, becomes corrupt.

Now the most important question comes up, how do they affect LoadRunner functioning?

As you might guess, memory leak, if left unattended and not corrected, could prove to be fatal. Memory leaks can be found out by running tests for long duration (say about an hour) and continuously checking memory usage.

Issues caused by memory leaks are essentially based on two variables for a standalone windows application 1) Frequency of usage 2) Size of memory leak. If either one or both are very high, the computer might come to a point when no memory is available for other applications. This could lead to a computer crash. If it is a network based application then you will also have to consider network traffic. If each network transaction causes a memory leak, then a high volume of network transactions could also prove dangerous.




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