Differences Between Optimizer Solution and Planner Solution in Project Server Events

Dear All,

Does anyone know the differences between Optimizer Solution and Planner Solution in Project Server? 

In http://msdn.microsoft.com/en-us/library/office/gg204879(v=office.15).aspx and http://msdn.microsoft.com/en-us/library/office/gg200978(v=office.15).aspx, they stated same definitions for both Optimizer Solution and Planner Solution.

Thank you.