Session Management - Oracle 10g/11g Data and Database Management Utilities - page 184

Scenario 1 : DAILY_PLAN is active. In this scenario all users connected through the
sales service are favored and automatically receive more CPU emphasis. The number
of CPU yields and the wait time are higher for users that gain access through the
datawarehouse service.
Scenario 2 : The instance switches to the NIGHTLY_PLAN . In this scenario all users
connected through the datawarehouse service are favored and automatically receive
more CPU emphasis. The number of CPU yields and the wait time are higher for
users that gain access through the sales service.