code: func physicalInitialize(p PhysicalPlan) {
  	for _, child := range p.GetChildren() {
  		physicalInitialize(child.(PhysicalPlan))
  	}
  	// initialize attributes
  	p.SetCorrelated()
  }
docs: // physicalInitialize will set value of some attributes after convert2PhysicalPlan process.
  // Currently, only attribute "correlated" is considered.