message: If one of the two sides of a join has a very low estimated cardinality - use a nested loop join over a IE Join or piecewise merge join
diff: @@ -254,6 +254,10 @@ unique_ptr<PhysicalOperator> PhysicalPlanGenerator::CreatePlan(LogicalComparison
  default:
  break;
  }
  + if (left->estimated_cardinality <= 5 || right->estimated_cardinality <= 5) {
  + can_iejoin = false;
  + can_merge = false;
  + }
  if (can_iejoin) {
  plan = make_unique<PhysicalIEJoin>(op, move(left), move(right), move(op.conditions), op.join_type,
  op.estimated_cardinality);
  