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

Memory-Leak

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.

References:

Wiki
Webopedia

Discussion

12 Responses to “What is memory leak, page fault and how they affect LoadRunner performance?”

  1. Hello,

    Good Informations on how memory leak and Page fault affects the Performance of a server.

    Pl keep on posting valuable informations.

    Thanks,
    Rajiv

    Posted by Rajiv | April 16, 2009, 11:41 pm
  2. Thanks Rajiv!

    Posted by Ankur | April 17, 2009, 2:13 pm
  3. Hi Ankur,

    I’m facing the memory leakage problem. While running the scripts i get ‘Out of memory’ error.
    I have opted discriptive programming.
    I’m using ‘.ini’ files to pass the value to the parameters.
    But i’m also using some variable inside the script to get the ROProperty
    Is there a way to free up the memory used by these variables?(during runtime)

    Thanks,
    Ritesh

    Posted by Ritesh | June 18, 2009, 12:42 pm
  4. Dear friends,
    Can any one share knw on Graphs.
    1) Hits per
    2) transaction resp graph
    3) Throughput graph
    4) Error graph etc

    Please explain with graphs.

    Thanks
    HK

    Posted by Hk | September 18, 2009, 5:02 pm
  5. how to identify bottle necks

    Posted by john | February 8, 2011, 10:20 pm
  6. Hi,
    Can u please explain with clear picture for the following graphs

    1) Hits per second
    2) transaction resp graph
    3) Throughput graph
    4) Response TIme graphetc

    Thanks in advance

    Posted by Ganesh | March 31, 2011, 7:47 pm
  7. Hi friends
    can you pls explain about memory leaks

    Posted by Prasad | June 7, 2011, 1:00 pm
  8. Hi Friends
    can you please answer for the question

    If a “Text in a Image” how can you find that using Content Checks

    Posted by Prasad | June 7, 2011, 1:02 pm
  9. Thanks for giving valuable information about memory leaks.
    Can any one help me in the concept of correlation?

    Posted by Pavan kumar | July 16, 2011, 4:25 pm
  10. Hi Ankur,

    I would to know do we have a shortcut key in Load Runner to Comment and uncomment … In Silk Performer it can be done using ctrl+q & ctrl+w..

    Posted by Raghavan | August 3, 2011, 1:14 pm
  11. Hi Ankur,

    I have recorded a script using load runner on a java based applicaton.
    There is a lookup field, when I click on this lookup a pop up comes and there are some checboxes, I select one of the value and click on ok.

    But during execution when I reach to this step then application shows fatalerror.jsp page,”https://test.mms.aon.com/TeamConnect/fatalError.jsp” and logout screen is displayed.

    Posted by Rakesh | April 19, 2012, 2:40 pm
  12. Easiest way to check the memory leaks is during the ramp down phase of the test or as you mentioned during a prolonged test, I got that but how do we determine there’s PAGE FAULT during monitoring or analysis?

    Posted by Crimson | May 22, 2012, 7:58 am

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