When targeting rules are defined for a feature flag, the rules are used to assign every customer to a treatment. This assignment is permanent until the targeting rules change. This permanence is useful because a customer should not see a different treatment in two back to back calls.
In some circumstances, it is useful to reassign customers to treatments without changing the targeting rules. This process is called reallocate in Split. The following are some examples:
- Your team enables a particular treatment for 10% of customers.
- During the release, a critical issue is found and the feature flag is immediately killed, sending all customers to the default treatment.
- Your team fixes the bug and wants to release again to 10% of customers.
- Your team does not want the same 10% to see the same treatment again, because they were exposed to the original issue. In other words, those customers were poisoned with regards to this treatment.
In this scenario, by reallocating traffic, each customer is reassigned to treatments, which spreads out the poisoned customers across the treatments rather than having them clustered in the on treatment of the feature flag.
Reallocation allows you to get an unbiased set of customers to give feedback on a feature being released, rather than relying on the feedback of those customers that were exposed to a critical bug.
To reallocate traffic, do the following:
- Click the … menu icon on the selected feature flag.
- Click Reallocate. A warning alert appears.
- Enter REALLOCATE in the warning alert.