Example Use Case: We have 100 users and at least 100 usernames as seed data and we want that each user is assigned a unique value and that it keeps that value from iteration to iteration. This will ensure that two users don’t log in with the same id at the same time.
This would be something similar to LoadRunner Select next row: Unique and Update value on: Once.
For setting this up, you’ll need to declare a property at the clip level and check “Property value is tied to the virtual user”. Check “Save value for analytics” to see the values used after the composition is played with the widget “Property Value Composition Analysis”. You can change the other settings depending on your needs, as for this example I’ve left the default values.
This setup works for a composition that uses the two most common setups: Infinite Clip Repeats (Renew Parallel Repeats Disabled for the Track, first image below) and Renew Parallel Repeats Enabled for the Track (Clip Repeats Disabled, second image below).
Find attached a composition with the second configuration (using Renew Parallel Repeats). Since it is set to renew parallel repeats, it will run infinitely, make sure to stop it after some iterations have completed to see the behavior. The composition is set to “Preview Mode”, meaning it will not be sending any traffic to the target but it will compute the seed data distribution.