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Author
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Topic: Is Think Time necessary
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rachana_barai
Member
Posts: 10
Registered: Aug 2002
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posted 08-21-2002 10:09 AM
    
Is it really necessary to replay the think time when running you VUscripts in the controller. or is it a good practice to ignore the think time. On what basis do you decide whether to play the think time or to ignore the think time------------------
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punekar
Advanced Guru
Posts: 588
Registered: Dec 2000
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posted 08-22-2002 12:12 AM
The Think time feature is provided to implement differing interarrival times for your particular workload. The proper usage of this function can help you simulate Poisson, Erlang and other arrival patterns.------------------
-Suresh Nageswaran
punekar@yahoo.com
Cognizant Technology Solutions,
Pune, India.
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JoeW
Advanced
Posts: 110
Registered: Jun 2001
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posted 08-22-2002 03:24 AM
Think time is vital for creating a load test that is as close to reality as possible. Ideally, to simulate 1000 real users on a system, you have 1000 virtual users, using the system in a similar way to real ones (i.e. with think time). This may not be possible if you're on a budget, and don't have that many virtual users available. You can then start to reduce think time in order to increase the workload on the system. As soon as you do this though, questions may be raised about the validity of the test (e.g. is 1000 users with think time the same as 500 users with half the think time ? maybe not) Typically you remove think time only in a stress test in which want to put abnormal load on a server.
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RSBarber
Moderator
Posts: 852
Registered: Jul 2002
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posted 08-22-2002 06:12 AM
Thanks JoeW - you beat me to the punch.rachana_barai - I have some articles that describe this concept in detail, but are slightly too large to attach here. Please email me directly and I will send them to you.
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Scott Barber
NOBLE(STAR
Sr. Performance Engineer
sbarber@noblestar.com
http://www.noblestar.com
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sauli1
Member
Posts: 16
Registered: Aug 2002
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posted 08-24-2002 05:46 AM
Interesting topic. Normally it's so much easier to create simple and "almost realistic" loads. Without reality simulation you cannot get all the interesting figures for the report but you can often achieve quite a good quality. Also an 'unrealistic' test is valid if it points out problems.This is good to know in projects with tight schedules. ------------------
Sauli Karhu
http://www.saunalahti.fi/sauli1
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perfamol
Member
Posts: 6
Registered: Aug 2002
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posted 09-05-2002 12:21 PM
Think Time is the time that the user is logged in the system but is not actively doing anything on the server. Think times are important in creating real-life scenarios. You omit think times only when you want to do a stress test on the server.Also introducing think times in the scripts are useful in simulating a particular trend of users hitting the system.
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Amol Khanapurkar
Performance Engineer
Enterprise System Performance, TCS
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