web test passes but the load test fails.


  • Hi All,

    continued from-http://social.msdn.microsoft.com/Forums/en-US/vstswebtest/thread/9fc74e58-9fc5-4641-b373-8ca1207698a0

    i am getting a lot of errors when i run a load test with 20 users.

    with 5-10 users the load test runs fine but not with more no of users.

    can any one please solve this issue?the errors i am getting is-502 bad gateway,500 internal server error, no hidden fields were found in the response, hidden_xxx not found etc...

    i have even kept think time of more that 25 secs on most of the imp pages.

    please find the settings i am using-

    Tuesday, January 31, 2012 6:14 AM

All replies

  • Are you collecting counters from the web server?  How does the memory and CPU look on the web server?  It is possible that your web server cannot handle the 20 user load?  The 500 and 502 errors are server errors and the problem will likely have to be addressed there.  If you are not gathering performance counters from the web server, start there and work through the issues with the application developers.
    Tuesday, January 31, 2012 11:51 AM
  • Also check if setting "parse dependent requests" to false solves the issue, see http://social.msdn.microsoft.com/Forums/en-US/vstswebtest/thread/17de40ba-e9ed-4032-bc66-e07f420d017f



    Wednesday, February 01, 2012 2:59 AM
  • Hi All,

    @anuj- i have done that and it didnt help.

    @Tim-counters are from webserver and the server is able to handle the load.this information i have right now.

    but main concern is "No hidden fields were found in the response." error.

    the developers say that because of this issue i am getting 500 error.

    has anyone encountered them before?if yes please tell me if this is an application issue/script issue.

    my application interacts with 2 servers.

    Wednesday, February 01, 2012 7:54 AM
  • rishabhw,

    Ah yes, the classic game of ping pong between QA and developement. My response to the developers would be "if you send me the hidden fields my test scripts will extract those fields and send them in later requests so we don't get the 500 errors." but life in a development org doesn't work that way. 

    Here is what I suggest:

    Modify this load test to use a step load pattern.  Start at 5 users and using increments of 2 or 3 step it up to 20 or 30 users or wherever you are confident you will get the 500 errors.  When the errors start happening, go to a different machine and manually perform the same test as your web performance tests (it may take many tries depending on the frequency of the errors).  If you can manually duplicate the error using the browser, you can rule out your test script and visual studio as the source of your problem. 

    Also note that often times when a request reports a 500 error it is a previous request that fails "quietly" so when you are trouble shooting the load test look for other problems not just the 500 error.  This is especially true of applications where the url is not changing with each request.

    Eaxample of a test that passes

    Request                           Response

    Login                               Home Page displayed

    Search for something      List of items displayed

    Click Item                         Item Details displayed

    Purchase                          Confirmation sent



    Example that fails:

    Request                           Response

    Login                               Home Page displayed

    Search for something      Timeout message is displayed (this is the root of the problem)

    Click Item                         Timeout message is displayed

    Purchase                          500 error (this is where the error is reported)



    • Proposed as answer by Lily Yin-MSFT Friday, February 03, 2012 4:43 AM
    Wednesday, February 01, 2012 5:17 PM
  • Hi Tim,

    i will do that and find if my scripts are fine or not.

    1 more question i have read it many times and u also say that its the previous req which is having trouble.

    many time the req should give 500 error but it shows 200 ok.so how do we know that what error occured in previous req and secondly in load test is it possible?

    does this happens mainly in redirecting req?or it can happen in any req?as in my case if i get a 500 error or any error the previous req is either 302 found or 200 ok.no time out or any other error message is displayed.

    Thursday, February 02, 2012 7:23 AM
  • I have seen this behavior most when the URL does not change with each page.  The only validation being done by default is checking the response url.  You can add validations to each page (for example something as simple as validationg some text on each page). see the section titled "Impact of Validation Rules on Load Testing" here: http://msdn.microsoft.com/en-us/library/bb385904.aspx

     When you are talking about 20 or so users having a bunch of validations will not be a big deal.  If you are trying to simulate 1000's of users you may want to avoid doing a bunch of validations in your load tests

    Thursday, February 02, 2012 3:14 PM
  • Hi Tim,

    thanx for your reply but just to inform you that in my load test i am not using response url property at all.

    i have deleted it form the webtest and then added that to my load test.

    if i had that property i got errors corresponding to it.secondly my webtest used to pass but load test failed.so i deleted it.

    so i got confused if it is a script prob or application problem.

    Friday, February 03, 2012 5:54 AM
  • Hello rishabhw,


    As your previous thread, if you don’t share a simple example with us, I think it is hard for us to resolve it. We only can provide some ways to narrow it, and then you should check it by yourself.

    I suggest you check which request generated this error, then check the specific request.


    If you are working with VS2010, there is a new feature named 'saving test logs' which makes it easier to debug problems that occur when running tests within a load test that do not occur when running the same tests outside the context of a load test. You can refer to the following article about the feature: http://blogs.msdn.com/b/billbar/archive/2009/06/09/vsts-2010-load-test-feature-saving-test-logs.aspx.


    Please refer http://social.msdn.microsoft.com/Forums/en/vstswebtest/thread/9e86436a-d83b-41a9-a1e0-62557f4a3ab3



    Friday, February 03, 2012 8:45 AM
  • i got this info from logs only, dunno how will i resolve it.does unbinding few parameters help in any case?
    Friday, February 03, 2012 10:12 AM
  • I don't follow.  did you go to this link and enable the "Saving Test Logs" feature? http://blogs.msdn.com/b/billbar/archive/2009/06/09/vsts-2010-load-test-feature-saving-test-logs.aspx

    Once you do that run the load test and click on the errors link or go to the test details table.  Click on the test log link and you should get a window that looks like this:


    find the fasilure and start clicking on the requests above the failing link and see if the web browser window gives you a clue.  I suspect as you click the links above the failures you will see an unexpected error page or something like that

    Friday, February 03, 2012 2:08 PM
  • Thanks for Lily and Tim’s help.

    Hi rishabhw,

    What about this problem now?
    Would you mind letting us know the result of Tim’s suggestion?

    Best Regards,

    Jack Zhai [MSFT]
    MSDN Community Support | Feedback to us

    Tuesday, February 07, 2012 3:14 AM
  • we are looking into this.

    no solution is giving a pin point ans.

    will keep every one updated

    Thursday, February 09, 2012 2:02 PM
  • Hi rishabhw,

    As Tim and Lily’s suggestions, you should check the detailed error message by yourself, and check your web test requests since we can’t
    repro your project with your reply. Or you can share us the detailed error information, we will try to provide help, but as my reply in another thread, if we can’t get your project, you would check it on your side one step by one step, and we just provide some suggestion to narrow this issue down. Thanks for your understanding. If you have any update about this issue, make free feel to let us know.

    In addition, would you mind changing this thread to “discussion”? If so, I think it will involve more customers for help.

    Best Regards,

    Jack Zhai [MSFT]
    MSDN Community Support | Feedback to us

    Monday, February 13, 2012 6:58 AM