public static PhysProj create(final RelNode input,

        final List<RexNode> projects, RelDataType rowType) {

      final RelOptCluster cluster = input.getCluster();

      final RelMetadataQuery mq = RelMetadataQuery.instance();

      final RelTraitSet traitSet =

          cluster.traitSet().replace(PHYSICAL)

              .replaceIfs(

                  RelCollationTraitDef.INSTANCE,

                  new Supplier<List<RelCollation>>() {

                    public List<RelCollation> get() {

                      return RelMdCollation.project(mq, input, projects);

                    }

                  });

      return new PhysProj(cluster, traitSet, input, projects, rowType);

    }