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Thursday 23 February 2017

Why Pacing and Think Time are so important in Performance Testing?



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16 comments :

  1. Hi

    Is there any component using in jmeter for stimulate pacing?

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    Replies
    1. Hi Rathina,

      There is no specific component for inserting pace time in the JMeter script. You have to use either "Timer" or "Test Action" sampler to simulate pacing.

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    2. Hi Gagandeep,
      i am using timer for think time and but i don't have idea about Test action.Let me check if i can use it for pacing. Thanks for update.

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    3. Hi, there is a plugin in jmeter "Stepping thread.." which has to be installed, to set the pacing.

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  2. HI,

    One question. Can pacing and think time be replaced?

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    Replies
    1. Please clarify your question. Are you aksing

      1. Can pacing be replaced by think time?

      or

      2. Can pacing and think time be replaced by any other component?

      or

      3. Can pacing or think time be replaced by programming logic?

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  3. Hi,

    Why can't we use think time instead of pacing at the end of iteration??

    Thanks.

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    Replies
    1. Hi Saleem,

      You can use think time (at the end of "Action") which can work as a pacing. But do remember that would be constant or random pacing according to your think time setting.

      Let's assume you need to set pacing like this which should not be calculated based on the execution time (overall response time). Then how could you achieve it. Since HP LoadRunner has given such option in pacing, so you can easily use it.

      Summary: You can use think time as a pacing for certain cases only, not all.

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  4. I am not getting below part mentioned by you:

    If there are 200 concurrent users and all logged in at the same time that makes 400Mb of memory in use. What about 400 users? 800Mb, but what if your max memory (heap) was only 512Mb? You would have got an out of memory error and found a problem with your system. If you did not use think time, then you would not have found this issue and it would have only be seen in Production

    Can u pls explain in brief?

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    Replies
    1. It is an example of achieving user concurrency on the server and find out the capacity of the server to handle the number of concurrent users. When you use think time then a user session lasts for a long time (real scenario) and the system will accommodate the connections as per its capacity and you can find out the capacity of the system to handle number of concurrent users at a time. This is the only case when you place Login and Logout in the "Action" part.

      If you do not use think time then the iteration will end-up soon (which is not a realistic scenario) and connections are available for other users. Hence you can not find out the true performance of the application.

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    2. Ok.. Thanks..

      And what is the difference between the load and concurrency.. when u say that "Pacing achieves Load while Think Time achieves Concurrency"

      How?

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    3. Think time is used to keep a user active, so that maximum concurrency can be achieved. Pacing is used to control the active user count (load). The more is pacing the less the active user load on the server.

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  5. Great job.. very good explanation..easy to understand for beginners

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  6. Hi Gagan,

    Could you please clarify to me, if i get a requirement, 100 iteration should be complete in an hour for Payment module and it includes 5 transaction. And my other scripts lets say add-to-card is also having some common transaction enclosed with lr_start and lr_end transaction function, then how i would be writting those common transaction in script because if i run these two script(payment and add-to-card) in controller results will overlap.

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    Replies
    1. Hi Amit,

      Add the prefix in the transaction name. Like:

      1. Payment_Login, Payment_Search, Payment_AddToCart
      2. ATC_Login, ATC_Search, ATC_AddToCart

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