Could some one please explain me what is the exact purpose of this checkbox. I have searched Pega documentation, but couldn't find anything. Please tell us some use cases of using and not using this check box.
This checkbox is there for backwards compatibility reasons, unchecked, it reverts to pre Pega 8.1 behavior for the way decision data was joined with the First matching for each input record yielded. When there is an input connector to the DDR shape, this checkbox should always be checked. If there is no input connector and you don't have any conditions defined, and you are not using the Globally optimized strategies (GOS) then there is a performance gain but unchecking this checkbox.