if (before instanceof LOCogroup) {
LOCogroup cg = (LOCogroup) before ;
cg.switchGroupByPlanOp(after, newNode);
}
if (before instanceof LOFRJoin) {
LOFRJoin frj = (LOFRJoin) before ;
frj.switchJoinColPlanOp(after, newNode);
}
// Visit all the inner plans of before and change their projects to
// connect to newNode instead of after.
// Find right inner plan(s) to visit