relations {
  root {
    input {
      project {
        common {
          emit {
            output_mapping: 3
            output_mapping: 4
          }
        }
        input {
          extension_leaf {
            common {
              direct {
              }
            }
            detail {
              [type.googleapis.com/mohair.SkyRel] {
                domain: "public"
                partition: "E-GEOD-100618"
                slices: 0
                slices: 1
                execstats {
                }
              }
            }
          }
        }
        expressions {
          selection {
            direct_reference {
              struct_field {
                field: 1
              }
            }
            root_reference {
            }
          }
        }
        expressions {
          selection {
            direct_reference {
              struct_field {
                field: 2
              }
            }
            root_reference {
            }
          }
        }
      }
    }
    names: "cell_id"
    names: "expression"
  }
}