If you’ve setup a Sitecore instance with MSSQL-based shared sessions, you’ve probably followed this guide:  https://doc.sitecore.net/sitecore_experience_platform/setting_up__maintaining/xdb/session_state/walkthrough_configure_a_shared_session_state_database_using_the_sql_server_provider.  Under the “Optimize SQL Server performance” section, you’ve seen a note to run a script to help boost performance.  Here’s what’s in the script for SC 8.1:

The long and short of that translates to moving both tables…