In the IBM® Marketing Platform configuration settings for the Interact runtime server, set the session timeout (Interact > sessionManagement > sessionTimeoutInSecs) to the smallest acceptable value.

Each Interact session contains some amount of session data in memory. The longer you maintain sessions, the more concurrent memory requirements you have. For example, if you are expecting 50 sessions per second, and each session can remain active for 20 minutes, you might require the memory to support 60,000 sessions at a time, if every session lasted the full 20 minutes.