case 1 : If i am setting the no of browser connections as 20 and setting the iteration as 40 .Does it mean that 20 users will do 2 iterations each ? or 20 users will do 40 iterations each .
case 2 : people say that , No.of iteration must be equal to greater than the No.of Browser connections ?
20 Browser connections, 1 iteration -this is a Invalid one
20 Browser connections, 20 or 40 iterations - this is a valid one.
The number of iterations is the total iterations for all (not each) vuser aka connection. So 100 iterations and 5 vusers (connections) means each user completes the script 20 times. With 10 connections, 100 iterations, (I prefer the term Vusers, as ACT will open and close connections within a script) each script will be repeated 10 times. Divide the total iterations by the connections and you get the number of times a script will be executed.
If the number of connections is greater than the number of iterations, then not all the 'connections' will execute, but it will still run.
What ACT does well is to ensure that the 'user' table maps to unique 'connections'. So if you have 20 'users' set up in the user table and set the connections to 20 (and iterations to a large number) ACT will use each user in turn so to allow for mutual exclusive issues. If the number of 'connections' is greater than the number of users then the user ID's will not be mutually exclusive.
I have 'experimented' with this as it was not clear from the docs.