Retrospective Dynamicity

Dynamicity refers to your ability to modify a concurrency limit after the user's account has been created. As a result, the user could have some pre-existing sessions after you change the concurrency limit. Retrospectivity refers to what happens to those pre-existing sessions when you change the concurrency limit.

In a case where a user has no concurrency limit imposed, to optimize performance, set the UserConcurrencyId field in the Current Sessions Table to NULL. No corresponding record for that user will be created in the Sbr_UserConcurrency table. This minimizes the number of accesses to the database because it is not necessary to update the Sbr_UserConcurrency table when no concurrency limit has been imposed on the user. This represents the no-retrospective-dynamicity model which is the model supported by Session State Register.