public int getIndexAmongIdColumns(final String idColumnName) {
    int index = 0;
    for (final ColumnSchema column : getIdColumns()) {
      if (column.getName().equals(idColumnName)) {
        return index;
      }
      index++;
    }
    return -1;
  }
Given the name of an ID column, return the index of this column among all ID columns, return -1
if not found.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/plan/relational/metadata/TableSchema.java